.session-page{
display:grid;
grid-template-columns:minmax(0,1fr) 220px;
gap:20px 28px;
max-width:1080px;
margin:0 auto;
margin-inline:auto;
padding:18px 22px 96px;
align-items:start;
animation:pageEnter var(--page-enter-dur) var(--ease) backwards;
}
@media (min-width:1600px){
  :root{--session-max:1240px}
  :root[data-layout="atlas"]{--session-max:1400px}
}
@media (min-width:1900px){
  :root{--session-max:1360px}
  :root[data-layout="atlas"]{--session-max:1520px}
}
@media (min-width:1600px){
  .session-page{max-width:min(var(--session-max), var(--content-max, 1360px))}
}
.session-page.v2-no-toc{
grid-template-columns:minmax(0,1fr);
}

.sess-head{
position:relative;
padding:12px 0 32px;
margin-bottom:40px;
border-bottom:1px solid var(--border-subtle);
}
.sess-head::after{
content:"";
position:absolute;
bottom:-1px;inset-inline-start:0;
width:56px;height:1px;
background:var(--accent);
}
.sess-head h1{
margin:0 0 16px;
font-size:clamp(22px,2.6vw,28px);font-weight:800;
line-height:1.45;letter-spacing:-.3px;
color:var(--text-primary);
}

.sess-ctx{
margin-bottom:32px;
padding:14px 18px;
background:var(--surface-raised);
border:1px solid var(--border-subtle);border-radius:12px;
}
.sess-ctx .chip{background:var(--surface-canvas);font-size:calc(12px * var(--fs-scale, 1));padding:4px 12px}

.sess-sec{
display:flex;align-items:baseline;gap:12px;
margin:52px 0 20px;
}
.sess-sec .bar{
width:4px;height:16px;border-radius:2px;
background:linear-gradient(180deg,var(--accent),var(--color-cyan));
flex-shrink:0;
}
.sess-sec h2{margin:0;font-size:calc(15.5px * var(--fs-scale, 1));font-weight:800;color:var(--text-primary)}
.sess-sec small{font-size:calc(12px * var(--fs-scale, 1));color:var(--text-tertiary);font-weight:600}

.rd-reader{display:flex;flex-direction:column}
.rd-intro{margin-bottom:40px}
.rd-reader > .rd-sec:first-of-type h2{margin-top:0}
.rd-outro{
margin-top:56px;
padding-top:24px;
border-top:1px solid var(--border-subtle);
}
.rd-sec{scroll-margin-top:96px}
.rd-sec h2{
display:flex;align-items:center;gap:12px;
margin:0 0 22px;
font-size:calc(20px * var(--fs-scale, 1));font-weight:800;
line-height:1.55;letter-spacing:-.2px;
color:var(--text-primary);
}
.rd-reader:not(.rd-reader--atlas) .rd-sec h2,
.doc-body .rd-sec h2{
margin-top:3.5rem;
}
.doc-body .rd-sec:first-child > h2{
margin-top:0;
}
.rd-sec-num{
flex-shrink:0;
display:inline-grid;place-items:center;
width:28px;height:28px;
border-radius:50%;
border:1.5px solid color-mix(in srgb,var(--accent) 45%,var(--border-strong));
background:color-mix(in srgb,var(--accent) 10%,transparent);
color:var(--accent);
font-size:calc(12.5px * var(--fs-scale, 1));font-weight:800;letter-spacing:0;
font-variant-numeric:tabular-nums;
}
.rd-h3{
margin:30px 0 12px;
font-size:calc(16px * var(--fs-scale, 1));font-weight:800;
line-height:1.6;letter-spacing:-.1px;
color:var(--text-primary);
}
.rd-h4{
margin:22px 0 8px;
font-size:calc(14.5px * var(--fs-scale, 1));font-weight:700;
line-height:1.6;
color:var(--text-primary);
}
.rd-p{
margin:0 0 18px;
font-size:calc(var(--font-size-base) * 1);
line-height:2.15;
color:var(--text-primary);
}
.rd-p:last-child{margin-bottom:0}
.rd-list{
margin:0 0 22px;
padding-inline-start:24px;
color:var(--text-primary);
}
.rd-list li{
margin-bottom:9px;
line-height:2.05;
}
.rd-list li::marker{color:var(--text-tertiary)}
.rd-hr{
border:none;
border-top:1px solid var(--border-subtle);
margin:48px 0;
position:relative;
}
.rd-hr::before{
content:"";position:absolute;
top:-1px;inset-inline-start:0;
width:32px;height:1px;
background:var(--accent);
}
.rd-math{
margin:26px 0;
position:relative;
padding-inline-start:18px;
}
.rd-math::before{
content:"";position:absolute;
inset-inline-start:0;top:14px;bottom:14px;
width:2px;border-radius:2px;
background:linear-gradient(180deg,var(--accent),transparent);
}
.rd-math-lbl{
display:block;
margin-bottom:6px;
font-size:calc(11.5px * var(--fs-scale, 1));font-weight:700;
letter-spacing:1.4px;text-transform:uppercase;
color:var(--text-tertiary);
}
.rd-math-body{
direction:ltr;text-align:center;
overflow-x:auto;overflow-y:hidden;
padding:2px 0;
}
.rd-math-body .katex-display{margin:0}
.fcard .ftex,.sess-formulas .ftex,.rd-formula-tex,.rd-math-body{scrollbar-width:thin;scrollbar-color:color-mix(in srgb,var(--text-primary) 34%,transparent) transparent}
.fcard .ftex::-webkit-scrollbar,.sess-formulas .ftex::-webkit-scrollbar,.rd-formula-tex::-webkit-scrollbar,.rd-math-body::-webkit-scrollbar{height:6px}
.fcard .ftex::-webkit-scrollbar-track,.sess-formulas .ftex::-webkit-scrollbar-track,.rd-formula-tex::-webkit-scrollbar-track,.rd-math-body::-webkit-scrollbar-track{background:transparent}
.fcard .ftex::-webkit-scrollbar-thumb,.sess-formulas .ftex::-webkit-scrollbar-thumb,.rd-formula-tex::-webkit-scrollbar-thumb,.rd-math-body::-webkit-scrollbar-thumb{background:color-mix(in srgb,var(--text-primary) 34%,transparent);border:none;border-radius:99px}
.fcard .ftex::-webkit-scrollbar-thumb:hover,.sess-formulas .ftex::-webkit-scrollbar-thumb:hover,.rd-formula-tex::-webkit-scrollbar-thumb:hover,.rd-math-body::-webkit-scrollbar-thumb:hover{background:color-mix(in srgb,var(--text-primary) 56%,transparent)}
.rd-formula{
margin:28px 0;
padding:16px 20px;
background:var(--surface-raised);
border:1px solid var(--border-subtle);
border-radius:12px;
}
:root[data-theme="dark"] .rd-formula{background:#0f1730}
:root[data-theme="light"] .rd-formula{background:#ffffff}
.rd-formula-head{
display:flex;align-items:center;gap:10px;
margin-bottom:12px;
}
.rd-formula-head b{
flex:1;min-width:0;
font-size:calc(13px * var(--fs-scale, 1));font-weight:700;
line-height:1.5;color:var(--text-primary);
}
.rd-formula-tex{
direction:ltr;text-align:center;
overflow-x:auto;overflow-y:hidden;
padding:4px 0;
}
.rd-formula-tex .katex-display{margin:0}
.rd-formula-use{
margin-top:12px;
padding-top:10px;
border-top:1px dashed var(--border-subtle);
font-size:calc(12.5px * var(--fs-scale, 1));color:var(--text-secondary);
line-height:1.9;
}
.rd-formula-vars{
display:flex;flex-wrap:wrap;gap:6px;
margin-top:10px;
}
.rd-formula-vars .v{
display:inline-flex;align-items:center;gap:6px;
padding:3px 9px;
background:var(--surface-canvas);
border:1px solid var(--border-subtle);border-radius:6px;
font-size:calc(11.5px * var(--fs-scale, 1));line-height:1.6;
color:var(--text-secondary);
}
.rd-widget{margin:36px 0;min-width:0}
.session-page[data-mode="detail"] .rd-widget{margin:2.4rem 0;padding:0;border:none;background:transparent}
.session-page[data-mode="detail"] .rd-widget::before{display:none}
.session-page[data-mode="detail"] .rd-widget .wt{margin:0 0 6px;gap:8px}
.session-page[data-mode="detail"] .rd-widget .wt h3{font-size:calc(15px * var(--fs-scale, 1));font-weight:800;color:var(--text-primary)}
.session-page[data-mode="detail"] .rd-widget .wbadge{margin-inline-start:0;font-size:calc(9.5px * var(--fs-scale, 1));padding:2px 8px}
.session-page[data-mode="detail"] .rd-widget .wd{font-size:calc(var(--font-size-base)*.95);color:var(--text-secondary);line-height:2;margin:0 0 14px}
.session-page[data-mode="detail"] .rd-widget .wgrid{grid-template-columns:1fr;gap:12px}
.session-page[data-mode="detail"] .rd-widget .wstage{
border-radius:12px;border:1px solid var(--border-subtle);
background:color-mix(in srgb,var(--surface-recess) 55%,transparent);
}
.session-page[data-mode="detail"] .rd-widget .wstage svg,
.session-page[data-mode="detail"] .rd-widget .wstage canvas{max-width:100%}
.session-page[data-mode="detail"] .rd-widget .ctls{
display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:2px 16px;
}
.session-page[data-mode="detail"] .rd-widget .winfo{margin-top:10px;gap:0}
.session-page[data-mode="detail"] .rd-widget .winfo .row{
background:transparent;border:none;border-top:1px dashed var(--border-subtle);
border-radius:0;padding:6px 2px;font-size:calc(12.5px * var(--fs-scale, 1));
}
.session-page[data-mode="detail"] .rd-widget .winfo .row:first-child{border-top:none}
.rd-callout{
margin:22px 0;
padding:14px 18px;
border-radius:12px;
border-inline-start:3px solid var(--accent);
background:color-mix(in srgb, var(--accent) 6%, transparent);
font-size:calc(var(--font-size-base) * .95);
line-height:1.95;
color:var(--text-primary);
}
.rd-callout > b{
display:block;
margin-bottom:8px;
font-size:calc(11.5px * var(--fs-scale, 1));font-weight:800;
letter-spacing:1.6px;text-transform:uppercase;
}
.rd-callout.rd-note{border-color:var(--color-blue);background:color-mix(in srgb,var(--color-blue) 6%,transparent)}
.rd-callout.rd-note > b{color:var(--color-blue)}
.rd-callout.rd-ex{border-color:var(--color-green);background:color-mix(in srgb,var(--color-green) 6%,transparent)}
.rd-callout.rd-ex > b{color:var(--color-green)}
.rd-callout.rd-warn{border-color:var(--color-amber);background:color-mix(in srgb,var(--color-amber) 6%,transparent)}
.rd-callout.rd-warn > b{color:var(--color-amber)}
.rd-callout.rd-key{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 8%,transparent)}
.rd-callout.rd-key > b{color:var(--accent)}
.rd-quote{
margin:26px 0;
padding:6px 20px;
border-inline-start:2px solid var(--accent);
font-style:italic;
font-size:calc(var(--font-size-base) * 1);
line-height:2.05;
color:var(--text-secondary);
}
.rd-quote cite{
display:block;
margin-top:8px;
font-size:calc(12.5px * var(--fs-scale, 1));font-style:normal;
color:var(--text-tertiary);
}
.rd-table{
width:100%;
border-collapse:collapse;
margin:24px 0;
font-size:calc(13.5px * var(--fs-scale, 1));
}
.rd-table th{
padding:10px 14px;
background:color-mix(in srgb,var(--accent) 8%,transparent);
color:var(--text-primary);
font-weight:700;
text-align:right;
border-bottom:2px solid color-mix(in srgb,var(--accent) 35%,transparent);
}
.rd-table td{
padding:10px 14px;
border-bottom:1px solid var(--border-subtle);
color:var(--text-secondary);
text-align:right;
line-height:1.9;
}
.rd-table tr:last-child td{border-bottom:none}
.rd-define{
margin:24px 0;
padding:14px 18px;
background:var(--surface-raised);
border:1px solid var(--border-subtle);
border-radius:12px;
}
:root[data-theme="dark"] .rd-define{background:#0f1730}
:root[data-theme="light"] .rd-define{background:#ffffff}
.rd-define-term{
display:inline-block;
margin-bottom:6px;
font-size:calc(13.5px * var(--fs-scale, 1));font-weight:800;
color:var(--accent);
}
.rd-define-body{
font-size:calc(var(--font-size-base) * .93);
line-height:1.95;
color:var(--text-primary);
}

@media(max-width:780px){
.rd-sec h2{font-size:calc(17px * var(--fs-scale, 1));gap:10px}
.rd-sec-num{font-size:calc(11px * var(--fs-scale, 1))}
.rd-h3{font-size:calc(15px * var(--fs-scale, 1))}
.rd-h4{font-size:calc(14px * var(--fs-scale, 1))}
.rd-p{font-size:calc(var(--font-size-base) * 1.02)}
.rd-formula{padding:14px 16px}
.rd-table{font-size:calc(12.5px * var(--fs-scale, 1))}
.rd-table th,.rd-table td{padding:8px 10px}
}

.session-page .exbox,
.session-page .notebox{
display:flex;flex-direction:column;gap:8px;
margin-top:20px;
padding:14px 16px 16px 18px;
border-radius:12px;
font-size:calc(var(--font-size-base) * .92);
line-height:2;
}
.session-page .exbox{background:color-mix(in srgb,var(--color-green) 7%,transparent)}
.session-page .notebox{background:color-mix(in srgb,var(--color-amber) 7%,transparent)}

.session-page .box-hd{
display:flex;align-items:center;gap:8px;
}
.session-page .box-ic{
display:grid;place-items:center;
flex:0 0 28px;width:28px;height:28px;
border-radius:9px;
}
.session-page .exbox .box-ic{
background:color-mix(in srgb,var(--color-green) 15%,transparent);
border:1px solid color-mix(in srgb,var(--color-green) 35%,transparent);
color:var(--color-green);
}
.session-page .notebox .box-ic{
background:color-mix(in srgb,var(--color-amber) 15%,transparent);
border:1px solid color-mix(in srgb,var(--color-amber) 35%,transparent);
color:var(--color-amber);
}
.session-page .box-ic svg{width:15px;height:15px;display:block}

.session-page .box-hd b{
margin:0;
font-size:calc(13px * var(--fs-scale, 1));font-weight:800;
letter-spacing:1.8px;text-transform:uppercase;
line-height:1.4;
}
.session-page .exbox .box-hd b{color:var(--color-green)}
.session-page .notebox .box-hd b{color:var(--color-amber)}

.session-page .box-tx{
min-width:0;
font-size:calc(var(--font-size-base) * .92);
line-height:2;
color:var(--text-primary);
}

.sess-formulas{
display:grid;
grid-template-columns:minmax(0,1fr);
gap:14px;
margin-top:14px;
width:100%;
}
.sess-formulas.single-col{
  column-width:auto;
  column-count:1;
}
.sess-formulas.single-col .fcard{
  display:block;
  width:auto;
  margin-bottom:14px;
}
.sess-formulas.single-col .fcard:last-child{
  margin-bottom:0;
}

@media (min-width:720px){
  .sess-formulas.single-col[data-count="2"]{
    display:flex;
    flex-wrap:nowrap;
    gap:14px;
    column-width:auto;
    column-count:auto;
  }
  .sess-formulas.single-col[data-count="2"] .fcard{
    flex:1 1 0;
    min-width:0;
    width:auto;
    display:block;
    margin-bottom:0;
    break-inside:auto;
    -webkit-column-break-inside:auto;
  }
}
.sess-formulas .fcard{
display:block;
width:100%;
page-break-inside:avoid;
margin:0;
padding:14px 16px 12px;
background:var(--surface-raised);
border:1px solid var(--border-subtle);border-radius:12px;
transition:border-color .2s var(--ease),transform .2s var(--ease),box-shadow .2s var(--ease);
}
:root[data-theme="dark"] .sess-formulas .fcard{background:#0f1730}
:root[data-theme="light"] .sess-formulas .fcard{background:#ffffff}
.sess-formulas .fcard::before{display:none}
.sess-formulas .fcard:hover{
border-color:color-mix(in srgb,var(--accent) 30%,var(--border-subtle));
}
.sess-formulas .fhead{
display:flex;align-items:center;gap:8px;
margin:0 0 8px;padding:0;border:none;
}
.sess-formulas .fhead b{
flex:1;min-width:0;
font-size:calc(12.5px * var(--fs-scale, 1));font-weight:700;
line-height:1.5;color:var(--text-primary);
}
.sess-formulas .fhead .badge{
flex-shrink:0;
padding:2px 8px;border-radius:5px;
font-size:calc(10px * var(--fs-scale, 1));font-weight:800;letter-spacing:1px;
}
.sess-formulas .ftex{
direction:ltr;text-align:center;
padding:4px 0 2px;
overflow-x:auto;overflow-y:hidden;
scrollbar-width:thin;
}
.sess-formulas .ftex::-webkit-scrollbar{height:5px}
.sess-formulas .ftex::-webkit-scrollbar-track{background:transparent}
.sess-formulas .ftex::-webkit-scrollbar-thumb{background:var(--border-strong);border-radius:99px;border:none}
.sess-formulas .ftex .katex-display{margin:0}
.sess-formulas .fuse{
margin:8px 0 0;padding-top:8px;
font-size:calc(11.5px * var(--fs-scale, 1));color:var(--text-secondary);line-height:1.85;
border-top:1px dashed var(--border-subtle);
}
.sess-formulas .fvars{
display:flex;flex-wrap:wrap;gap:5px;
margin-top:8px;
}
.sess-formulas .fvars .v{
display:inline-flex;align-items:center;gap:5px;
padding:2px 8px;
background:var(--surface-canvas);
border:1px solid var(--border-subtle);border-radius:6px;
font-size:calc(11px * var(--fs-scale, 1));line-height:1.6;
}
.sess-formulas .fvars .v code{
color:var(--color-cyan);font-weight:700;font-size:calc(11.5px * var(--fs-scale, 1));
}

.sess-cards-list{display:flex;flex-direction:column;gap:10px}

.ccard{
padding:18px 22px 20px;
background:var(--surface-raised);
border:1px solid var(--border-subtle);border-radius:12px;
scroll-margin-top:96px;
transition:border-color .2s var(--ease);
}
:root[data-theme="dark"] .ccard{background:#0f1730}
:root[data-theme="light"] .ccard{background:#ffffff}

.ccard-kicker{
display:flex;align-items:center;gap:8px;
margin-bottom:10px;
}
.ccard-num{
display:inline-grid;place-items:center;
min-width:22px;height:20px;padding:0 7px;
background:color-mix(in srgb,var(--accent) 14%,transparent);
border:1px solid color-mix(in srgb,var(--accent) 32%,transparent);
border-radius:6px;
color:var(--accent);
font-size:calc(11.5px * var(--fs-scale, 1));font-weight:800;
font-variant-numeric:tabular-nums;line-height:1;
}

.ccard h3{
margin:0 0 10px;
font-size:calc(15px * var(--fs-scale, 1));font-weight:800;
line-height:1.55;letter-spacing:-.1px;
color:var(--text-primary);
}
.ccard-body{
font-size:calc(14px * var(--fs-scale, 1));line-height:1.95;color:var(--text-secondary);
}
.ccard-def{margin:0 0 10px}
.ccard-pts{list-style:none;margin:0;padding:0}
.ccard-pts li{
position:relative;
padding-inline-start:18px;
margin-bottom:6px;
color:var(--text-primary);
}
.ccard-pts li::before{
content:"";position:absolute;
inset-inline-start:4px;top:11px;
width:5px;height:1.5px;border-radius:2px;
background:var(--text-tertiary);
}

.sess-tips ol{
list-style:none;counter-reset:t;
margin:0;padding:0;
display:flex;flex-direction:column;gap:8px;
}
.sess-tips ol li{
counter-increment:t;
display:flex;align-items:flex-start;gap:12px;
padding:12px 16px;
background:var(--surface-raised);
border:1px solid var(--border-subtle);border-radius:10px;
font-size:calc(var(--font-size-base) * .92);
line-height:1.95;color:var(--text-primary);
}
:root[data-theme="dark"] .sess-tips ol li{background:#0f1730}
:root[data-theme="light"] .sess-tips ol li{background:#ffffff}
.sess-tips ol li::before{
content:counter(t,persian);
display:grid;place-items:center;
flex:0 0 24px;width:24px;height:24px;
margin-top:3px;
background:color-mix(in srgb,var(--color-amber) 14%,transparent);
border:1px solid color-mix(in srgb,var(--color-amber) 35%,transparent);
border-radius:7px;
color:var(--color-amber);
font-size:calc(12px * var(--fs-scale, 1));font-weight:800;
font-variant-numeric:tabular-nums;
}

details.fn{
margin:34px 0 0;
padding:16px 0 0;
background:none;border:none;border-radius:0;
border-top:1px solid var(--border-subtle);
font-size:calc(12.5px * var(--fs-scale, 1));color:var(--text-secondary);
}
details.fn summary{
display:flex;align-items:center;gap:8px;
cursor:pointer;list-style:none;
color:var(--text-tertiary);font-weight:800;
font-size:calc(11px * var(--fs-scale, 1));letter-spacing:1.4px;text-transform:uppercase;
}
details.fn summary::-webkit-details-marker{display:none}
details.fn summary svg{width:13px;height:13px;opacity:.7;flex-shrink:0}
details.fn summary::after{
content:"";flex:1;height:1px;
background:linear-gradient(to left,var(--border-subtle),transparent);
}
details.fn[open] summary{margin-bottom:12px;color:var(--accent)}
details.fn ul{margin:0;list-style:none}
details.fn li{
position:relative;
padding-inline-start:16px;
margin-bottom:8px;line-height:1.9;
}
details.fn li::before{
content:"";position:absolute;inset-inline-start:2px;top:.7em;
width:5px;height:5px;border-radius:50%;
background:var(--border-strong);
}
.session-page[data-mode="detail"] details.fn{max-width:42rem}

.sess-toc{
position:sticky;top:88px;
max-height:calc(100vh - 112px);
overflow-y:auto;overscroll-behavior:contain;
padding:0 0 24px;
scrollbar-width:thin;
}
.sess-toc::-webkit-scrollbar{width:4px}
.sess-toc::-webkit-scrollbar-thumb{background:var(--border-strong);border-radius:999px}
.sess-toc::-webkit-scrollbar-track{background:transparent}

@media (max-width:1160px){
.session-page{grid-template-columns:minmax(0,1fr);gap:0;max-width:800px}
.sess-toc{display:none}
}
@media (max-width:1060px){
.session-page{padding:16px 18px 72px}
}
@media (max-width:780px){
.sess-formulas{column-width:auto;column-count:1}
}
@media (max-width:760px){
.sess-head{padding:8px 0 24px;margin-bottom:32px}
.sess-head h1{font-size:calc(22px * var(--fs-scale, 1))}
.concept h3{font-size:calc(17px * var(--fs-scale, 1))}
.concept .def,
.concept .pts li{font-size:calc(15.5px * var(--fs-scale, 1));line-height:2}
.sess-formulas .fcard{padding:12px 14px 10px}
}

.v2-session-main{
min-width:0;
display:flex;flex-direction:column;
gap:18px;
}
.v2-toc{
position:sticky;top:86px;
max-height:calc(100vh - 112px);
overflow:auto;
padding:14px;
border:1px solid var(--border-subtle);
border-radius:var(--radius-sm);
background:color-mix(in srgb,var(--surface-nested) 92%,transparent);
box-shadow:none;
}

.v2-topbar{
display:flex;align-items:center;justify-content:space-between;
gap:12px;
padding:9px 14px;
border:1px solid var(--border-subtle);
border-radius:999px;
background:color-mix(in srgb,var(--surface-raised) 88%,transparent);
backdrop-filter:blur(12px);
-webkit-backdrop-filter:blur(12px);
}
.v2-crumb{
display:flex;align-items:center;gap:8px;
min-width:0;overflow:hidden;white-space:nowrap;
font-size:calc(12.5px * var(--fs-scale, 1));color:var(--text-secondary);
}
.v2-chapter{color:var(--accent);font-weight:850}
.v2-dot{opacity:.5}
.v2-top-actions{
display:flex;align-items:center;gap:8px;
flex-shrink:0;
}
.v2-top-actions .btn,
.v2-top-actions .icon-btn{
height:34px;
padding-inline:12px;
border-radius:999px;
font-size:calc(12px * var(--fs-scale, 1));
}

.v2-hero{
position:relative;isolation:isolate;overflow:hidden;
padding:28px 26px 24px;
border:1px solid var(--border-subtle);
border-radius:var(--radius-lg);
background:var(--surface-raised);
box-shadow:
  inset 0 1px 0 rgba(255,255,255,.03),
  var(--shadow-overlay);
}
.v2-hero::before{
content:"";position:absolute;z-index:-1;
inset-inline-start:26px;top:0;
width:64px;height:2px;
background:var(--accent);opacity:.9;
border-radius:0 0 2px 2px;
pointer-events:none;
}
.v2-hero::after{display:none}
.v2-title{
margin:0 0 10px;
font-size:clamp(1.65rem,2.4vw,2.35rem);
line-height:1.25;font-weight:900;letter-spacing:-.02em;
color:var(--text-primary);
}
.v2-objective{
margin:0;max-width:72ch;
color:var(--text-secondary);
line-height:1.9;font-size:calc(14.5px * var(--fs-scale, 1));
}
.v2-meta{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}
.v2-chip{
display:inline-flex;align-items:center;
border:1px solid var(--border-subtle);
background:color-mix(in srgb,var(--surface-nested) 88%,transparent);
color:var(--text-secondary);
border-radius:999px;
padding:5px 10px;
font-size:calc(11.5px * var(--fs-scale, 1));font-weight:750;line-height:1.6;
}
.v2-prereq{
color:var(--color-amber);
border-color:color-mix(in srgb,var(--color-amber) 35%,var(--border-subtle));
}
.v2-session-page[data-v2-mode="cards"] .v2-hero{padding:20px 22px}
.v2-session-page[data-v2-mode="cards"] .v2-objective{
font-size:calc(13.5px * var(--fs-scale, 1));
display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;
overflow:hidden;
}
.v2-session-page[data-v2-mode="detail"] .v2-hero{
background:none;border:none;box-shadow:none;border-radius:0;
padding:6px 0 18px;overflow:visible;
}
.v2-session-page[data-v2-mode="detail"] .v2-hero::before,
.v2-session-page[data-v2-mode="detail"] .v2-hero::after{display:none}
.v2-session-page[data-v2-mode="detail"] .v2-title{
font-size:clamp(1.9rem,3.2vw,2.7rem);
line-height:1.4;letter-spacing:-.01em;
}
.v2-session-page[data-v2-mode="detail"] .v2-objective{
max-width:42rem;
margin-top:14px;padding-top:14px;
border-top:1px solid var(--border-subtle);
font-size:calc(var(--font-size-base) * 1.05);
line-height:2.1;color:var(--text-secondary);
}
.v2-session-page[data-v2-mode="detail"] .v2-meta{margin-top:14px}
.v2-session-page[data-v2-mode="detail"] .v2-chip{
background:transparent;border-color:var(--border-subtle);
color:var(--text-tertiary);font-size:calc(11px * var(--fs-scale, 1));
}

.v2-old-head,
.v2-old-title{display:none !important}

.mode-switch{
display:inline-flex;padding:3px;gap:2px;
border-radius:999px;border:1px solid var(--border-subtle);
background:var(--surface-nested);
}
.mode-sw-btn{
border:none;background:transparent;color:var(--text-secondary);
font-family:inherit;font-size:calc(12.5px * var(--fs-scale, 1));font-weight:700;
padding:7px 14px;border-radius:999px;cursor:pointer;
transition:background .18s var(--ease-ios),color .18s var(--ease-ios);
}
.mode-sw-btn.on{
background:var(--surface-raised);color:var(--text-primary);
box-shadow:0 1px 4px rgba(0,0,0,.12);
}
.mode-sw-btn:hover:not(.on):not(:disabled){color:var(--text-primary)}
.mode-sw-btn:disabled{opacity:.42;cursor:not-allowed;filter:saturate(.35)}

.rd-banner{
display:flex;flex-direction:column;gap:8px;
padding:14px 16px;margin-bottom:22px;border-radius:14px;
border:1px solid var(--border-subtle);
}
.rd-banner-main b{display:block;font-size:calc(13.5px * var(--fs-scale, 1));font-weight:800;color:var(--text-primary);margin-bottom:2px}
.rd-banner-main span{font-size:calc(12.5px * var(--fs-scale, 1));color:var(--text-secondary);line-height:1.6}

.rd-banner{display:none;
background:color-mix(in srgb,var(--color-violet) 10%,var(--surface-raised));
border-color:color-mix(in srgb,var(--color-violet) 30%,var(--border-subtle));
position:sticky;top:72px;z-index:20;
backdrop-filter:blur(12px);
}
.rd-banner-bar{
height:3px;border-radius:99px;background:var(--border-subtle);overflow:hidden;
}
.rd-banner-bar i{
display:block;height:100%;width:0;border-radius:99px;
background:linear-gradient(90deg,var(--color-violet),var(--color-cyan));
transition:width .15s linear;
}

.session-page[data-mode="detail"] .rd-p{
font-size:calc(var(--font-size-base) * 1.02);
line-height:2.05;margin-bottom:1.1em;color:var(--text-primary);
}
.session-page[data-mode="detail"] .rd-sec{
margin-bottom:2.5rem;padding-bottom:0.5rem;
}
.session-page[data-mode="detail"] .rd-sec h2{
font-size:calc(1.35rem * var(--fs-scale, 1));margin:3.5rem 0 1.25rem;line-height:1.5;
}
.session-page[data-mode="detail"] .sess-ctx{display:none}

.v2-session-page[data-v2-mode="cards"] .v2-meta{display:none}

.session-page[data-mode="overview"] .sess-ctx{display:none}
.rd-outro{
margin-top:2.5rem;padding:1.25rem 1.35rem;border-radius:16px;
background:var(--surface-nested);border:1px solid var(--border-subtle);
}
.rd-outro-lbl{
font-size:calc(11px * var(--fs-scale, 1));font-weight:800;color:var(--text-tertiary);
letter-spacing:.04em;margin-bottom:10px;
}
.rd-table-wrap{overflow-x:auto;margin:1.2rem 0;border-radius:12px;border:1px solid var(--border-subtle)}
.rd-table{width:100%;border-collapse:collapse;font-size:calc(13px * var(--fs-scale, 1))}
.rd-table th,.rd-table td{padding:10px 12px;border-bottom:1px solid var(--border-subtle);text-align:right}
.rd-table th{background:var(--surface-nested);color:var(--color-cyan);font-weight:700}
.rd-figure{margin:1.5rem 0;text-align:center}
.rd-figure img{max-width:100%;border-radius:12px;border:1px solid var(--border-subtle)}
.rd-figure figcaption{font-size:calc(12.5px * var(--fs-scale, 1));color:var(--text-tertiary);margin-top:8px}

.session-page[data-mode="cards"] .concept{margin-bottom:12px}

@media (max-width:1060px){
.v2-topbar{
  flex-wrap:wrap;
  border-radius:16px;
  gap:10px;
  padding:10px 12px;
}
.v2-top-actions{
  width:100%;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:flex-end;
  gap:8px;
}
.v2-crumb{width:100%}
.mode-switch{flex-shrink:0}
.mode-sw-btn{padding:6px 12px;font-size:calc(12px * var(--fs-scale, 1))}
.rd-banner{display:none;
  position:static;
  top:auto;
}
.session-page[data-mode="detail"] .rd-reader{
  max-width:none;
}
.session-page{
  padding:12px 14px 80px;
  width:100%;
  max-width:100%;
  box-sizing:border-box;
  overflow-x:clip;
}
.v2-session-page,.v2-session-main{
  min-width:0;
  width:100%;
  max-width:100%;
}
.rd-banner{display:none;padding:12px;margin-bottom:16px}
}

@media(max-width:1160px){
.session-page{grid-template-columns:minmax(0,1fr)}
}

.rd-meta-line{font-size:calc(12px * var(--fs-scale, 1));color:var(--text-tertiary);margin-bottom:16px;font-weight:600}
.rd-progress-wrap{
display:flex;align-items:center;gap:12px;
margin-bottom:14px;
}
.rd-progress-bar{
flex:1;height:4px;border-radius:99px;
background:var(--border-subtle);overflow:hidden;
}
.rd-progress-bar i{
display:block;height:100%;width:0;border-radius:99px;
background:linear-gradient(90deg,var(--accent),var(--color-cyan));
transition:width .15s linear;
}
.rd-progress-txt{
font-size:calc(11.5px * var(--fs-scale, 1));font-weight:700;color:var(--text-tertiary);
min-width:36px;text-align:center;
font-variant-numeric:tabular-nums;
}
@media (min-width:1800px){
.session-page{max-width:1240px}
.session-page[data-mode="detail"] .rd-reader{max-width:46rem}
}

.sess-accordion{
  border:1px solid var(--border-subtle);
  border-radius:14px;
  background:var(--surface-raised);
  margin-bottom:12px;
  overflow:hidden;
}
.sess-accordion summary{
  display:flex;align-items:center;gap:12px;
  padding:16px 20px;
  cursor:pointer;list-style:none;
  user-select:none;
  -webkit-tap-highlight-color:transparent;
  transition:background .2s var(--ease-ios);
}
.sess-accordion summary::-webkit-details-marker{display:none}
.sess-accordion summary:hover{background:var(--surface-nested)}
.sess-accordion summary .bar{
  width:4px;height:16px;border-radius:2px;
  background:linear-gradient(180deg,var(--accent),var(--color-cyan));
  flex-shrink:0;
}
.sess-accordion summary h2{
  margin:0;font-size:calc(15.5px * var(--fs-scale, 1));font-weight:800;
  color:var(--text-primary);flex:1;min-width:0;
}
.sess-accordion summary small{
  font-size:calc(12px * var(--fs-scale, 1));color:var(--text-tertiary);font-weight:600;
  white-space:nowrap;
}
.sess-accordion > summary::after{
  content:"";
  display:block;
  width:8px;height:8px;
  border-right:2px solid var(--text-tertiary);
  border-bottom:2px solid var(--text-tertiary);
  transform:rotate(45deg);
  transition:transform .25s var(--ease-ios);
  flex-shrink:0;opacity:.7;
}
html[dir="rtl"] .sess-accordion > summary::after{transform:rotate(-45deg)}
.sess-accordion[open] > summary::after{transform:rotate(-135deg)}
html[dir="rtl"] .sess-accordion[open] > summary::after{transform:rotate(135deg)}
.sess-accordion.closing > summary::after{transform:rotate(45deg)}
html[dir="rtl"] .sess-accordion.closing > summary::after{transform:rotate(-45deg)}
.sess-accordion.closing summary{border-bottom-color:transparent}

.rd-formula, .rd-widget, .rd-math{
  border-inline-start:3px solid var(--accent);
  padding-inline-start:16px;
}
.rd-widget{border-inline-start-color:var(--color-green)}
.rd-math{border-inline-start-color:var(--color-cyan)}
.sess-notes{margin:12px 0 0;border:1px solid var(--border-subtle);border-radius:12px;background:var(--surface-nested);padding:0}
.sess-notes summary{padding:10px 14px;cursor:pointer;font-weight:700;font-size:calc(13px * var(--fs-scale, 1));color:var(--text-secondary);list-style:none}
.sess-notes summary::-webkit-details-marker{display:none}
.sess-notes textarea{width:100%;border:none;background:transparent;color:var(--text-primary);padding:0 14px 12px;font-family:inherit;font-size:calc(14px * var(--fs-scale, 1));line-height:1.7;resize:vertical;min-height:72px}
.sess-notes textarea:focus{outline:none}

.v2-top-actions{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
}
.v2-top-actions .sess-bm-btn,
.v2-top-actions .btn{
  height:34px;padding:0 12px;border-radius:999px;font-size:calc(12.5px * var(--fs-scale, 1));font-weight:700;
  border:1px solid var(--border-subtle);background:var(--surface-nested);color:var(--text-primary);
  font-family:inherit;cursor:pointer;white-space:nowrap;
}
.v2-top-actions .sess-bm-btn[aria-pressed="true"]{
  background:color-mix(in srgb,var(--color-amber) 16%,var(--surface-raised));
  border-color:color-mix(in srgb,var(--color-amber) 40%,var(--border-subtle));
  color:var(--color-amber);
}
.sess-notes-v2,
.sess-notes{
  display:block !important;
  margin:12px 0 18px;
  border:1px solid var(--border-subtle);
  border-radius:14px;
  background:var(--surface-nested);
  overflow:hidden;
}
.sess-notes-v2 summary,
.sess-notes summary{
  padding:12px 16px;cursor:pointer;font-weight:800;font-size:calc(13px * var(--fs-scale, 1));
  color:var(--text-secondary);list-style:none;user-select:none;
}
.sess-notes-v2 summary::-webkit-details-marker,
.sess-notes summary::-webkit-details-marker{display:none}
.sess-notes-v2 textarea,
.sess-notes textarea{
  display:block;width:100%;box-sizing:border-box;
  border:none;border-top:1px solid var(--border-subtle);
  background:var(--surface-raised);color:var(--text-primary);
  padding:12px 16px;font-family:inherit;font-size:calc(14px * var(--fs-scale, 1));line-height:1.75;
  resize:vertical;min-height:88px;
}
.sess-notes-v2 textarea:focus,
.sess-notes textarea:focus{outline:none}
@media(max-width:1060px){
  .v2-top-actions{width:100%;justify-content:flex-start}
}

.ov-panel{
  border:1px solid var(--border-subtle);
  border-radius:var(--radius-sm,14px);
  background:var(--surface-raised);
  padding:14px 16px 16px;
  margin-bottom:8px;
}

.ov-head{
  display:flex; gap:14px; align-items:flex-start;
  justify-content:space-between;
  padding-bottom:12px; margin-bottom:12px;
  border-bottom:1px solid var(--border-subtle);
}
.ov-head-text{ flex:1; min-width:0; }
.ov-kicker{
  display:block; font-size:calc(11px * var(--fs-scale, 1)); letter-spacing:.04em;
  color:var(--accent); font-weight:800; margin-bottom:4px;
}
.ov-lead{
  margin:0; color:var(--text-secondary);
  font-size:calc(13px * var(--fs-scale, 1)); line-height:1.75;
  max-width:56ch;
}

.ov-stats{
  display:flex; flex-wrap:wrap; gap:6px;
  margin-bottom:12px;
}
.ov-stat{
  display:inline-flex; align-items:baseline; gap:5px;
  padding:5px 11px;
  background:var(--surface-nested);
  border:1px solid var(--border-subtle);
  border-radius:8px;
  font-size:calc(12px * var(--fs-scale, 1)); color:var(--text-secondary);
  font-weight:600;
  line-height:1;
}
.ov-stat b{
  font-size:calc(14px * var(--fs-scale, 1)); color:var(--accent);
  font-weight:900; line-height:1;
}

.ov-chip{
  font-size:calc(11.5px * var(--fs-scale, 1)); padding:3px 9px;
  border-radius:999px;
  border:1px solid var(--border-subtle);
  background:var(--surface-nested);
  color:var(--text-secondary); font-weight:600;
  line-height:1.4;
}

@media (max-width: 720px){

    .session-page{padding:16px 12px 56px}

    .ccard{padding:18px 14px 18px}
  .concept{padding:20px 14px 18px}
  .sess-cards-list{gap:10px}

    .session-page .exbox,
  .session-page .notebox{
    padding:14px 14px 16px;
    gap:8px;
    margin-top:14px;
  }
  .session-page .box-ic{
    flex:0 0 24px;width:24px;height:24px;
  }
  .session-page .box-ic svg{width:13px;height:13px}
  .session-page .box-hd b{font-size:calc(11.5px * var(--fs-scale, 1));letter-spacing:1.4px}

    .ccard-pts li{padding-inline-start:14px}
  .ccard-body{font-size:calc(13.5px * var(--fs-scale, 1))}

    .sess-formulas .fcard{padding:10px 8px 8px}
  .rd-formula{padding:10px 8px}

    .sess-head{padding:4px 0 16px;margin-bottom:20px}
  .sess-head h1{font-size:calc(18px * var(--fs-scale, 1));line-height:1.55}

    .sess-accordion summary{padding:10px 8px;gap:8px}
  .sess-accordion summary h2{font-size:calc(14px * var(--fs-scale, 1))}
  .sess-accordion summary small{font-size:calc(11px * var(--fs-scale, 1))}

    .widget{padding:10px 8px 12px;border-radius:14px}

    details.fn{padding:12px 0 0;font-size:calc(12px * var(--fs-scale, 1))}
  details.fn summary{font-size:calc(10.5px * var(--fs-scale, 1))}
}

@media (max-width: 720px){
  .session-page[data-mode="detail"]{
    padding: 18px 18px 64px;
  }
  .session-page[data-mode="detail"] .rd-p{
    font-size: calc(var(--font-size-base) * 1.03);
    line-height: 2.15;
    margin-bottom: 1.2em;
  }
  .session-page[data-mode="detail"] .rd-sec{
    margin-bottom: 2rem;
  }
  .session-page[data-mode="detail"] .rd-h3{
    margin: 24px 0 10px;
  }
  .session-page[data-mode="detail"] .rd-sec h2{
    margin: 0 0 18px;
  }
  .session-page[data-mode="detail"] .rd-callout{
    padding: 12px 14px;
  }
}

@media (max-width: 420px){
  .session-page[data-mode="detail"]{
    padding: 14px 14px 56px;
  }
}

@media (max-width: 420px){
  .session-page{padding:10px 4px 48px}
  .ccard{padding:12px 6px 12px}
  .concept{padding:14px 6px 12px}
  .session-page .exbox,
  .session-page .notebox{padding:9px 6px 9px 8px}
  .sess-head h1{font-size:calc(16.5px * var(--fs-scale, 1))}
  .ccard-body{font-size:calc(13px * var(--fs-scale, 1))}
}

@media (max-width: 420px){
  .session-page{padding:12px 10px 56px}
  .ccard{padding:12px 12px 14px}
  .concept{padding:14px 12px 12px}
  .session-page .exbox,
  .session-page .notebox{padding:9px 10px 10px}
  .sess-head h1{font-size:calc(17.5px * var(--fs-scale, 1))}
}

.rd-quiz{
  display:flex; flex-direction:column; gap:.5rem;
  margin:1.4rem 0; padding:1.1rem 1.2rem;
  border:1px solid var(--border-subtle); border-radius:14px;
  background:var(--surface-raised);
}
.rd-quiz-title{
  font-size:calc(.95rem * var(--fs-scale, 1)); font-weight:800; line-height:1.8;
  margin-bottom:.4rem; color:var(--text-primary);
  padding-inline-start:.55rem;
  border-inline-start:3px solid var(--accent);
}
.rd-quiz-o{
  display:flex; align-items:center; gap:.7rem;
  padding:.7rem .95rem; border-radius:11px;
  border:1px solid var(--border-subtle);
  background:var(--surface-nested); color:var(--text-primary);
  font-family:inherit; font-size:calc(.86rem * var(--fs-scale, 1)); text-align:start;
  cursor:pointer;
  transition:border-color .2s var(--ease), background .2s var(--ease), transform .2s var(--ease);
}
.rd-quiz-o:hover{
  border-color:color-mix(in srgb,var(--accent) 40%,var(--border-subtle));
  transform:translateX(-3px);
}
.rd-quiz-o .lt{
  display:grid; place-items:center;
  width:24px; height:24px; border-radius:8px; flex:none;
  background:var(--surface-raised);
  font-family:'Space Grotesk',monospace; font-size:calc(.74rem * var(--fs-scale, 1)); font-weight:700;
}
.rd-quiz-tx{ line-height:1.8; }
.rd-quiz-o.right{
  border-color:color-mix(in srgb,var(--color-green) 55%,var(--border-subtle));
  background:color-mix(in srgb,var(--color-green) 12%,var(--surface-nested));
}
.rd-quiz-o.right .lt{ background:var(--color-green); color:#0b0f1e; }
.rd-quiz-o.wrong{
  border-color:color-mix(in srgb,var(--color-rose) 55%,var(--border-subtle));
  background:color-mix(in srgb,var(--color-rose) 12%,var(--surface-nested));
}
.rd-quiz-o.wrong .lt{ background:var(--color-rose); color:#fff; }
.rd-quiz[data-locked="1"] .rd-quiz-o{ cursor:default; pointer-events:none; }
.rd-quiz-exp{
  margin-top:.3rem; padding:.75rem .9rem;
  border-radius:11px;
  font-size:calc(.82rem * var(--fs-scale, 1)); line-height:2; color:var(--text-secondary);
  border-inline-start:3px solid color-mix(in srgb,var(--accent) 55%,transparent);
  background:color-mix(in srgb,var(--accent) 6%,transparent);
  animation:fadeIn .4s var(--ease);
}

.rd-flash-deck{ margin:1.4rem 0; }
.rd-flash-title{
  font-size:calc(.85rem * var(--fs-scale, 1)); font-weight:800; margin-bottom:.7rem;
  color:var(--text-primary);
}
.rd-flash-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(220px,1fr));
  gap:.8rem;
}
.rd-flash{
  perspective:1200px; height:170px;
  cursor:pointer; outline:none;
}
.rd-flash:focus-visible{
  outline:2px solid var(--accent); outline-offset:3px; border-radius:14px;
}
.rd-flash-in{
  position:relative; width:100%; height:100%;
  transition:transform .65s var(--ease);
  transform-style:preserve-3d;
}
.rd-flash.flipped .rd-flash-in{ transform:rotateY(180deg); }
.rd-flash-f,.rd-flash-b{
  position:absolute; inset:0;
  backface-visibility:hidden; -webkit-backface-visibility:hidden;
  border-radius:14px; border:1px solid var(--border-subtle);
  padding:14px 1rem 1rem;
  display:grid;
  grid-template-rows:auto 1fr;
  gap:.5rem;
  text-align:center;
}
.rd-flash-f{ background:var(--surface-raised); }
.rd-flash-b{
  transform:rotateY(180deg);
  background:linear-gradient(140deg,
    color-mix(in srgb,var(--accent) 14%,var(--surface-raised)),
    var(--surface-raised));
  border-color:color-mix(in srgb,var(--accent) 35%,var(--border-subtle));
}
.rd-flash-kick{
  justify-self:center;
  font-size:calc(.62rem * var(--fs-scale, 1)); font-weight:800; letter-spacing:.14em;
  color:var(--text-tertiary); text-transform:uppercase;
}
.rd-flash-tx{
  align-self:center;
  justify-self:center;
  font-size:calc(.9rem * var(--fs-scale, 1)); font-weight:600; line-height:1.75;
  color:var(--text-primary);
}

.rd-compare-wrap{
  margin:1.3rem 0;
  overflow-x:auto;
  border-radius:12px;
  border:1px solid var(--border-subtle);
}
.rd-compare{
  width:100%; border-collapse:collapse; font-size:calc(.85rem * var(--fs-scale, 1));
}
.rd-compare th{
  padding:.7rem 1rem;
  background:color-mix(in srgb,var(--accent) 8%,var(--surface-nested));
  color:var(--text-primary); font-weight:800;
  text-align:start;
  border-bottom:2px solid color-mix(in srgb,var(--accent) 30%,transparent);
}
.rd-compare td{
  padding:.6rem 1rem;
  border-bottom:1px solid var(--border-subtle);
  color:var(--text-secondary);
  text-align:start; line-height:1.9;
}
.rd-compare tr:last-child td{ border-bottom:none; }
.rd-compare tbody tr:hover td{
  background:var(--surface-nested); color:var(--text-primary);
}

.rd-steps-block{ margin:1.4rem 0; }
.rd-steps-title{
  font-size:calc(.88rem * var(--fs-scale, 1)); font-weight:800; margin-bottom:.7rem;
  color:var(--text-primary);
}
.rd-steps-list{ display:flex; flex-direction:column; gap:.6rem; }
.rd-steps-item{
  display:flex; gap:.9rem; align-items:flex-start;
  padding:.85rem 1rem; border-radius:12px;
  background:var(--surface-raised);
  border:1px solid var(--border-subtle);
  transition:border-color .25s var(--ease), transform .25s var(--ease);
}
.rd-steps-item:hover{
  border-color:color-mix(in srgb,var(--accent) 30%,var(--border-subtle));
  transform:translateX(-3px);
}
.rd-steps-n{
  flex:none; width:28px; height:28px; border-radius:9px;
  display:grid; place-items:center;
  background:linear-gradient(135deg,var(--accent),color-mix(in srgb,var(--accent) 55%,#fff));
  color:var(--text-on-accent);
  font-family:'Space Grotesk',monospace; font-size:calc(.8rem * var(--fs-scale, 1)); font-weight:800;
}
.rd-steps-c{ flex:1; min-width:0; line-height:2; }
.rd-steps-t{
  display:block; font-size:calc(.85rem * var(--fs-scale, 1)); font-weight:800;
  margin-bottom:.2rem; color:var(--text-primary);
}
.rd-steps-c > div,
.rd-steps-c > p{ font-size:calc(.87rem * var(--fs-scale, 1)); color:var(--text-secondary); }

.rd-keys-block{ margin:1.4rem 0; }
.rd-keys-title{
  font-size:calc(.88rem * var(--fs-scale, 1)); font-weight:800; margin-bottom:.7rem;
  color:var(--text-primary);
}
.rd-keys-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(240px,1fr));
  gap:.6rem;
}
.rd-key{
  display:flex; gap:.7rem; align-items:flex-start;
  padding:.75rem .9rem; border-radius:11px;
  background:var(--surface-raised);
  border:1px solid var(--border-subtle);
  transition:border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.rd-key:hover{
  border-color:color-mix(in srgb,var(--accent) 32%,var(--border-subtle));
  box-shadow:var(--shadow-base);
}
.rd-key-n{
  flex:none; width:22px; height:22px; border-radius:7px;
  display:grid; place-items:center;
  background:color-mix(in srgb,var(--accent) 14%,transparent);
  color:var(--accent);
  font-family:'Space Grotesk',monospace; font-size:calc(.72rem * var(--fs-scale, 1)); font-weight:800;
}
.rd-key-tx{
  font-size:calc(.84rem * var(--fs-scale, 1)); line-height:1.9; color:var(--text-primary);
}

.rd-atlas-flow .rd-quiz,
.rd-atlas-flow .rd-flash-deck,
.rd-atlas-flow .rd-compare-wrap,
.rd-atlas-flow .rd-steps-block,
.rd-atlas-flow .rd-keys-block{
  column-span:all;
  break-inside:avoid;
}

.session-page[data-mode="review"] .rd-sec {
  margin-bottom: 2.4rem;
}
.session-page[data-mode="review"] .rd-sec:last-of-type {
  margin-bottom: 0;
}
.session-page[data-mode="review"] .rd-sec h2 {
  margin-bottom: 18px;
}

.rd-review-formulas {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 1.2rem 0;
}
.rd-review-formula {
  padding: 14px 16px 12px;
  border-radius: 13px;
  border: 1px solid var(--border-subtle);
  background: var(--surface-raised);
  position: relative;
}
.rd-review-formula::before {
  content: "";
  position: absolute;
  inset-inline-start: 0;
  top: 14px;
  bottom: 14px;
  width: 3px;
  border-radius: 0 2px 2px 0;
  background: var(--accent);
  opacity: .55;
}
.rd-rf-head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-inline-start: 8px;
  margin-bottom: 8px;
}
.rd-rf-num {
  display: grid;
  place-items: center;
  min-width: 22px;
  height: 20px;
  padding: 0 7px;
  border-radius: 6px;
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  color: var(--accent);
  font-size: calc(11.5px * var(--fs-scale, 1));
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  line-height: 1;
}
.rd-rf-title {
  flex: 1;
  min-width: 0;
  font-size: calc(.92rem * var(--fs-scale, 1));
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.5;
}
.rd-rf-tex {
  padding: 6px 0 8px;
  padding-inline-start: 8px;
  overflow-x: auto;
  overflow-y: hidden;
}
.rd-rf-tex .katex-display { margin: 0; }
.rd-rf-use {
  margin: 6px 0 0;
  padding-inline-start: 8px;
  padding-top: 8px;
  border-top: 1px dashed var(--border-subtle);
  font-size: calc(.82rem * var(--fs-scale, 1));
  line-height: 1.85;
  color: var(--text-secondary);
}

.rd-checklist {
  margin: 1.4rem 0;
  padding: 16px 18px 14px;
  border-radius: 14px;
  border: 1px solid var(--border-subtle);
  background: var(--surface-raised);
  transition: border-color .25s var(--ease);
}
.rd-checklist-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}
.rd-checklist-head b {
  font-size: calc(.95rem * var(--fs-scale, 1));
  font-weight: 800;
  color: var(--text-primary);
}
.rd-checklist-count {
  font-family: var(--font-mono, monospace);
  font-size: calc(.78rem * var(--fs-scale, 1));
  font-weight: 700;
  color: var(--text-tertiary);
  font-variant-numeric: tabular-nums;
}
.rd-checklist-bar {
  height: 4px;
  border-radius: 99px;
  background: color-mix(in srgb, var(--border-strong) 50%, transparent);
  overflow: hidden;
  margin-bottom: 14px;
}
.rd-checklist-bar > i {
  display: block;
  height: 100%;
  width: 0;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--accent), var(--color-cyan));
  transition: width .35s var(--ease);
}
.rd-checklist-items {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.rd-check {
  position: relative;
  display: grid;
  grid-template-columns: 22px 1fr;
  gap: 12px;
  align-items: start;
  padding: 10px 12px;
  border-radius: 11px;
  border: 1px solid transparent;
  background: var(--surface-nested);
  cursor: pointer;
  transition: border-color .18s var(--ease), background .18s var(--ease);
}
.rd-check:hover { border-color: var(--border-strong); }
.rd-check input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}
.rd-check-box {
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border-radius: 7px;
  border: 1.5px solid var(--border-strong);
  background: transparent;
  color: transparent;
  transition: background .18s var(--ease),
              border-color .18s var(--ease),
              color .18s var(--ease);
}
.rd-check-box svg { width: 13px; height: 13px; }
.rd-check input:checked ~ .rd-check-box {
  background: linear-gradient(135deg, var(--accent), var(--accent-2, var(--accent)));
  border-color: transparent;
  color: var(--accent-ink, #fff);
}
.rd-check input:checked ~ .rd-check-tx {
  color: var(--text-tertiary);
  text-decoration: line-through;
  text-decoration-color: color-mix(in srgb, var(--text-tertiary) 60%, transparent);
}
.rd-check-tx {
  font-size: calc(.88rem * var(--fs-scale, 1));
  line-height: 1.75;
  color: var(--text-primary);
  padding-top: 1px;
}
.rd-checklist.is-done {
  border-color: color-mix(in srgb, var(--color-green) 40%, var(--border-subtle));
}
.rd-checklist.is-done .rd-checklist-bar > i {
  background: linear-gradient(90deg, var(--color-green), var(--color-cyan));
}

@media (max-width: 620px){
  .rd-flash-grid{ grid-template-columns:1fr; }
  .rd-flash{ height:150px; }
  .rd-keys-grid{ grid-template-columns:1fr; }
  .rd-quiz{ padding:.9rem .85rem; }
  .rd-quiz-o{ padding:.65rem .75rem; font-size:calc(.83rem * var(--fs-scale, 1)); }
  .rd-compare th,
  .rd-compare td{ padding:.5rem .7rem; font-size:calc(.8rem * var(--fs-scale, 1)); }
  .rd-steps-item{ padding:.7rem .8rem; }
}

.fcard {
  border-inline-start-width: 0;
}
.fcard:hover {
  border-inline-start-width: 0;
}

.rd-math::before {
  display: none;
}

.rd-formula,
.rd-widget {
  border-top-width: 0;
  border-bottom-width: 0;
  border-inline-end-width: 0;
    border-start-start-radius: 0;
  border-end-start-radius: 0;
}

[dir="rtl"] .rd-formula,
[dir="rtl"] .rd-widget {
  border-top-right-radius: 0;
  border-bottom-right-radius: 0;
}

.rd-atlas-grid .rd-formula,
.rd-atlas-grid .rd-widget,
.rd-atlas-grid .rd-math {
    background-clip: padding-box;
}