/* Layout concept: an examination prospectus. Left-aligned text columns, ruled tables,
   and one recurring figure, the OMR answer bubble, which carries marks, progress and the question palette. */
:root {
  --paper: #FDFCFB; --paper-2: #F5F1EF; --paper-3: #ECE6E3;
  --ink: #1D1A1F; --ink-2: #5A5258; --ink-3: #857B80;
  --rule: #DED6D3; --rule-2: #C9BEBB;
  --alta: #8C1C13; --alta-strong: #6F140D; --alta-tint: #F6E4E1; --alta-line: #D9A29C; --on-alta: #FFF8F3;
  --marigold: #F2A541; --marigold-tint: #FCEBCB; --marigold-ink: #7A4A05;
  --ok: #1E6B45; --ok-tint: #DDEFE5;
  --shadow: 0 1px 2px rgba(60, 20, 15, .06), 0 8px 24px -12px rgba(60, 20, 15, .18);
  --serif: "Source Serif 4", "Noto Serif Bengali", Georgia, "Times New Roman", serif;
  --sans: "IBM Plex Sans", "Noto Sans Bengali", "Segoe UI", system-ui, sans-serif;
  --bn: "Noto Serif Bengali", "Source Serif 4", serif;
  --band: #8C1C13; --band-ink: #FFF8F3; --band-soft: #F3CFC9; --band-line: #B8564D; --band-hover: #7A1810;
  --wrap: 1120px; --gut: max(20px, env(safe-area-inset-left, 0px));
  --gut-r: max(20px, env(safe-area-inset-right, 0px));
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #161316; --paper-2: #1F1B1F; --paper-3: #2A2529;
    --ink: #EEE8E6; --ink-2: #B5ABAE; --ink-3: #8C8286;
    --rule: #342E32; --rule-2: #4A4146;
    --alta: #EE8377; --alta-strong: #F5A096; --alta-tint: #3A1D1B; --alta-line: #7A3A34; --on-alta: #1B0E0D;
    --marigold: #F2A541; --marigold-tint: #40300F; --marigold-ink: #F6C378;
    --ok: #7CCBA0; --ok-tint: #17322A;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 10px 28px -12px rgba(0, 0, 0, .7);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #161316; --paper-2: #1F1B1F; --paper-3: #2A2529;
  --ink: #EEE8E6; --ink-2: #B5ABAE; --ink-3: #8C8286;
  --rule: #342E32; --rule-2: #4A4146;
  --alta: #EE8377; --alta-strong: #F5A096; --alta-tint: #3A1D1B; --alta-line: #7A3A34; --on-alta: #1B0E0D;
  --marigold: #F2A541; --marigold-tint: #40300F; --marigold-ink: #F6C378;
  --ok: #7CCBA0; --ok-tint: #17322A;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 10px 28px -12px rgba(0, 0, 0, .7);
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 16px/1.6 var(--sans); font-variant-numeric: tabular-nums; -webkit-tap-highlight-color: transparent; }
::selection { background: var(--marigold); color: #1D1A1F; }
:focus-visible { outline: 2px solid var(--alta); outline-offset: 2px; border-radius: 3px; }
a { color: var(--alta); text-decoration-thickness: 1px; text-underline-offset: .18em; }
a:hover { color: var(--alta-strong); text-decoration-thickness: 2px; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.15; letter-spacing: -.015em; margin: 0; text-wrap: balance; }
h1 { font-size: clamp(2.1rem, 1.2rem + 3.6vw, 3.5rem); letter-spacing: -.025em; }
h2 { font-size: clamp(1.5rem, 1.2rem + 1.2vw, 2rem); }
h3 { font-size: 1.2rem; line-height: 1.3; }
p { margin: 0; }
button, input, select { font: inherit; color: inherit; }
button { touch-action: manipulation; }
[lang="bn"] { font-family: var(--bn); line-height: 1.85; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--ink); color: var(--paper); padding: 8px 12px; z-index: 50; }
.skip:focus { left: 8px; }

.wrap { max-width: var(--wrap); margin-inline: auto; padding-left: var(--gut); padding-right: var(--gut-r); }
.lede { font-size: 1.14rem; color: var(--ink-2); max-width: 62ch; }
.muted { color: var(--ink-2); } .small { font-size: .875rem; }
.measure { max-width: 68ch; }
.stack > * + * { margin-top: 1rem; }

/* demo strip */
.demo { background: var(--ink); color: var(--paper); font-size: .8125rem; }
.demo .wrap { display: flex; flex-wrap: wrap; gap: 6px 18px; align-items: center; padding-block: 7px; }
.demo strong { font-weight: 600; color: var(--marigold); }
.demo select, .demo button { background: transparent; color: inherit; border: 1px solid color-mix(in srgb, var(--paper) 35%, transparent); border-radius: 4px; padding: 3px 8px; min-height: 28px; }
.demo select option { background: var(--paper); color: var(--ink); }
.demo button { cursor: pointer; } .demo button:hover { border-color: var(--paper); }
.demo .sp { margin-left: auto; display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }

/* header */
.top { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 20; background: color-mix(in srgb, var(--paper) 94%, transparent); backdrop-filter: saturate(1.4) blur(8px); border-bottom: 1px solid var(--rule); }
.top .wrap { display: flex; align-items: center; gap: 20px; min-height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand img { width: 38px; height: 38px; display: block; }
.brand b { font-family: var(--serif); font-weight: 700; font-size: 1.3rem; letter-spacing: .14em; }
.brand span { font-family: var(--bn); color: var(--ink-3); font-size: .95rem; padding-left: 10px; border-left: 1px solid var(--rule-2); }
.nav { display: flex; gap: 2px; margin-left: auto; align-items: center; }
.nav a { color: var(--ink-2); text-decoration: none; padding: 8px 12px; border-radius: 6px; font-size: .95rem; font-weight: 500; }
.nav a:hover { color: var(--ink); background: var(--paper-2); }
.nav a[aria-current="page"] { color: var(--alta); box-shadow: inset 0 -2px 0 var(--alta); border-radius: 0; }
.nav .btn { margin-left: 10px; }
.nav a.btn, .nav a.btn:hover { color: var(--on-alta); background: var(--alta); border-radius: 6px; }
.nav a.btn.ghost, .nav a.btn.ghost:hover { color: var(--ink); background: transparent; }
.menu-btn { display: none; margin-left: auto; background: none; border: 1px solid var(--rule-2); border-radius: 6px; min-height: 40px; padding: 0 12px; cursor: pointer; }
@media (max-width: 860px) {
  .brand span { display: none; }
  .menu-btn { display: inline-flex; align-items: center; gap: 8px; }
  .nav { display: none; position: absolute; left: 0; right: 0; top: 100%; background: var(--paper); border-bottom: 1px solid var(--rule); flex-direction: column; align-items: stretch; padding: 8px var(--gut-r) 16px var(--gut); box-shadow: var(--shadow); }
  .nav.open { display: flex; }
  .nav a { padding: 12px 8px; border-bottom: 1px solid var(--rule); border-radius: 0; }
  .nav a[aria-current="page"] { box-shadow: inset 3px 0 0 var(--alta); padding-left: 14px; }
  .nav .btn { margin: 12px 0 0; }
}

/* buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; padding: 0 18px; border-radius: 6px; border: 1px solid var(--alta); background: var(--alta); color: var(--on-alta); font-weight: 600; font-size: .95rem; text-decoration: none; cursor: pointer; transition: background-color .15s, border-color .15s, transform .1s; }
.btn:hover { background: var(--alta-strong); border-color: var(--alta-strong); color: var(--on-alta); }
.btn:active { transform: translateY(1px); }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--rule-2); }
.btn.ghost:hover { border-color: var(--ink); background: var(--paper-2); color: var(--ink); }
.btn.sm { min-height: 36px; padding: 0 12px; font-size: .875rem; }
.btn[disabled], .btn[aria-disabled="true"] { opacity: .55; cursor: not-allowed; }
.btn svg, .tag svg, .row-link svg { width: 16px; height: 16px; flex: none; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }

/* tags */
.tag { display: inline-flex; align-items: center; gap: 5px; font-size: .78rem; font-weight: 600; padding: 2px 8px; border-radius: 4px; border: 1px solid var(--rule-2); color: var(--ink-2); white-space: nowrap; line-height: 1.5; }
.tag.free { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 45%, transparent); background: var(--ok-tint); }
.tag.paid { color: var(--marigold-ink); border-color: color-mix(in srgb, var(--marigold) 60%, transparent); background: var(--marigold-tint); }
.tag.open { color: var(--alta); border-color: var(--alta-line); background: var(--alta-tint); }
mark { background: linear-gradient(transparent 55%, var(--marigold) 55%, var(--marigold) 92%, transparent 92%); color: inherit; padding: 0 .08em; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) mark { background: linear-gradient(transparent 62%, color-mix(in srgb, var(--marigold) 55%, transparent) 62%, color-mix(in srgb, var(--marigold) 55%, transparent) 94%, transparent 94%); } }
:root[data-theme="dark"] mark { background: linear-gradient(transparent 62%, color-mix(in srgb, var(--marigold) 55%, transparent) 62%, color-mix(in srgb, var(--marigold) 55%, transparent) 94%, transparent 94%); }

/* sections */
main { display: block; min-height: 60vh; }
.sec { padding-block: clamp(44px, 6vw, 80px); border-top: 1px solid var(--rule); }
.sec.first { border-top: 0; padding-top: clamp(36px, 5vw, 64px); }
.sec > .wrap > h2 + p { margin-top: 12px; }
.sec-head { display: grid; gap: 12px; margin-bottom: 28px; }
.split { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(28px, 5vw, 72px); align-items: start; }
@media (max-width: 900px) { .split { grid-template-columns: minmax(0, 1fr); } }
.crumbs { font-size: .875rem; color: var(--ink-3); margin-bottom: 14px; }
.crumbs a { color: var(--ink-2); }

/* hero */
.hero { padding-block: clamp(36px, 6vw, 84px) clamp(40px, 6vw, 72px); }
.hero .split { grid-template-columns: minmax(0, 6fr) minmax(0, 6fr); align-items: center; }
@media (max-width: 900px) { .hero .split { grid-template-columns: minmax(0, 1fr); } }
.hero h1 + .lede { margin-top: 20px; } .hero .actions { margin-top: 28px; }
.hero .foot { margin-top: 18px; font-size: .875rem; color: var(--ink-3); }

/* the paper map: one bubble per mark */
.pmap { border: 1px solid var(--rule); border-radius: 10px; background: var(--paper); box-shadow: var(--shadow); }
.pmap header { padding: 16px 20px 12px; border-bottom: 1px solid var(--rule); display: flex; flex-wrap: wrap; justify-content: space-between; gap: 4px 16px; align-items: baseline; }
.pmap header b { font-family: var(--serif); font-size: 1.05rem; }
.pmap header span { font-size: .8125rem; color: var(--ink-3); }
.pmap ol { list-style: none; margin: 0; padding: 6px 0; }
.pmap li a { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 2px 14px; padding: 9px 20px; text-decoration: none; color: var(--ink); align-items: center; }
.pmap li a:hover { background: var(--paper-2); }
.pmap .hn { font-size: .9rem; font-weight: 500; min-width: 0; }
.pmap .mk { font-family: var(--serif); font-weight: 600; font-size: 1.05rem; text-align: right; grid-row: span 2; }
.pmap .mk small { font: 400 .75rem var(--sans); color: var(--ink-3); display: block; }
.pmap footer { padding: 10px 20px 14px; border-top: 1px solid var(--rule); font-size: .8125rem; color: var(--ink-3); display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.bub { display: flex; flex-wrap: wrap; gap: 4px; }
.bub i { width: 13px; height: 13px; border-radius: 50%; border: 1.5px solid var(--alta-line); background: var(--alta-tint); display: block; }
.bub i.on { background: var(--alta); border-color: var(--alta); }
.pmap li a:hover .bub i { background: var(--alta); border-color: var(--alta); }
@media (prefers-reduced-motion: no-preference) {
  .pmap .bub i { animation: ink .5s cubic-bezier(.16, 1, .3, 1) both; animation-delay: calc(var(--i) * 9ms); }
  @keyframes ink { from { transform: scale(.4); background: var(--alta); border-color: var(--alta); } }
}

/* tables */
.tw { overflow-x: auto; border: 1px solid var(--rule); border-radius: 10px; background: var(--paper); }
table { border-collapse: collapse; width: 100%; font-size: .95rem; }
th, td { text-align: left; padding: 12px 16px; border-bottom: 1px solid var(--rule); vertical-align: top; }
thead th { font-size: .78rem; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); background: var(--paper-2); white-space: nowrap; }
tbody tr:last-child > * { border-bottom: 0; }
tbody th { font-weight: 600; }
td.num, th.num { text-align: right; white-space: nowrap; }
tr.total > * { font-weight: 600; background: var(--paper-2); }
.facts th { width: 11.5rem; color: var(--ink-2); font-weight: 500; }
@media (max-width: 600px) { .facts th, .facts td { display: block; width: auto; } .facts th { padding-bottom: 0; border-bottom: 0; font-size: .8125rem; } .facts td { padding-top: 2px; } }

/* three parts */
.parts { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; border-top: 2px solid var(--ink); }
.parts > div { padding: 22px 28px 8px 0; } .parts > div + div { padding-left: 28px; border-left: 1px solid var(--rule); }
.parts h3 { margin-bottom: 8px; } .parts p { color: var(--ink-2); } .parts dl { margin: 14px 0; font-size: .9rem; display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; }
.parts dt { color: var(--ink-3); } .parts dd { margin: 0; }
@media (max-width: 820px) { .parts { grid-template-columns: minmax(0, 1fr); } .parts > div, .parts > div + div { padding: 20px 0; border-left: 0; border-bottom: 1px solid var(--rule); } }

/* calendar */
.cal { list-style: none; margin: 0; padding: 0; border-left: 2px solid var(--rule-2); }
.cal li { display: grid; grid-template-columns: 8.5rem minmax(0, 1fr); gap: 4px 16px; padding: 10px 0 10px 22px; position: relative; }
.cal li::before { content: ""; position: absolute; left: -8px; top: 15px; width: 14px; height: 14px; border-radius: 50%; border: 1.5px solid var(--alta-line); background: var(--paper); }
.cal li.past::before { background: var(--alta); border-color: var(--alta); }
.cal li.next::before { background: var(--marigold); border-color: var(--marigold); }
.cal time { font-weight: 600; white-space: nowrap; } .cal li.past { color: var(--ink-2); }
@media (max-width: 520px) { .cal li { grid-template-columns: minmax(0, 1fr); } }

/* head blocks (classes / notes) */
.head { border: 1px solid var(--rule); border-radius: 10px; background: var(--paper); margin-top: 18px; scroll-margin-top: 84px; }
.head > header { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 6px 20px; padding: 18px 20px; align-items: start; }
.head > header p { color: var(--ink-2); font-size: .9rem; margin-top: 4px; }
.head .mk { text-align: right; font-family: var(--serif); font-size: 1.5rem; font-weight: 600; line-height: 1; }
.head .mk small { display: block; font: 400 .75rem var(--sans); color: var(--ink-3); margin-top: 4px; }
.lyr { border-top: 1px solid var(--rule); }
.lyr > .lh { display: flex; flex-wrap: wrap; gap: 6px 12px; align-items: center; padding: 10px 20px; background: var(--paper-2); font-size: .875rem; }
.lyr > .lh b { font-weight: 600; } .lyr > .lh .r { margin-left: auto; color: var(--ink-2); }
.rows { list-style: none; margin: 0; padding: 0; }
.rows li { border-top: 1px solid var(--rule); }
.row-link { display: grid; grid-template-columns: 2.2rem minmax(0, 1fr) auto; gap: 12px; align-items: center; padding: 11px 20px; text-decoration: none; color: var(--ink); min-height: 48px; }
a.row-link:hover { background: var(--paper-2); color: var(--ink); }
.row-link .n { color: var(--ink-3); font-size: .875rem; }
.row-link .st { display: flex; gap: 8px; align-items: center; font-size: .8125rem; color: var(--ink-2); text-align: right; }
.row-link.wait { color: var(--ink-2); }
.dot { width: 14px; height: 14px; border-radius: 50%; border: 1.5px solid var(--alta-line); background: var(--alta-tint); flex: none; display: inline-block; }
.dot.on { background: var(--alta); border-color: var(--alta); }
@media (max-width: 560px) { .row-link { grid-template-columns: 1.6rem minmax(0, 1fr); } .row-link .st { grid-column: 2; justify-content: flex-start; } }
.jump { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 20px; }
.jump a { font-size: .875rem; padding: 6px 12px; border: 1px solid var(--rule-2); border-radius: 999px; text-decoration: none; color: var(--ink-2); }
.jump a:hover { border-color: var(--alta); color: var(--alta); }

/* notice / panel */
.panel { border: 1px solid var(--rule); border-radius: 10px; padding: 20px; background: var(--paper); }
.panel.tint { background: var(--paper-2); }
.note { background: var(--marigold-tint); color: var(--ink); border-radius: 8px; padding: 12px 16px; font-size: .9rem; }
.note b { color: var(--marigold-ink); }
.grid2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
@media (max-width: 760px) { .grid2 { grid-template-columns: minmax(0, 1fr); } }

/* price */
.price { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border: 1px solid var(--rule); border-radius: 10px; overflow: hidden; }
.price > div { padding: 22px; display: flex; flex-direction: column; gap: 10px; } .price > div + div { border-left: 1px solid var(--rule); }
.price .amt { font-family: var(--serif); font-size: 2rem; font-weight: 600; line-height: 1; } .price .amt small { font: 400 .875rem var(--sans); color: var(--ink-3); }
.price p { color: var(--ink-2); font-size: .92rem; flex: 1; }
.price .both { background: var(--paper-2); }
@media (max-width: 820px) { .price { grid-template-columns: minmax(0, 1fr); } .price > div + div { border-left: 0; border-top: 1px solid var(--rule); } }

/* forms */
.form { max-width: 26rem; display: grid; gap: 16px; }
.field { display: grid; gap: 6px; } .field label { font-weight: 600; font-size: .9rem; }
.field input { min-height: 46px; padding: 0 12px; border: 1px solid var(--rule-2); border-radius: 6px; background: var(--paper); font-size: 1rem; width: 100%; caret-color: var(--alta); }
.field input:focus-visible { outline-offset: 0; border-color: var(--alta); }
.field .hint { font-size: .8125rem; color: var(--ink-3); } .field .err { font-size: .8125rem; color: var(--alta); font-weight: 600; }
.field input[aria-invalid="true"] { border-color: var(--alta); }
.pre { display: flex; } .pre span { display: flex; align-items: center; padding: 0 12px; border: 1px solid var(--rule-2); border-right: 0; border-radius: 6px 0 0 6px; background: var(--paper-2); color: var(--ink-2); } .pre input { border-radius: 0 6px 6px 0; }
.otp input { letter-spacing: .5em; font-size: 1.25rem; font-weight: 600; text-align: center; }

/* lesson */
.player { background: #0E0C0E; border-radius: 10px; overflow: hidden; aspect-ratio: 16 / 9; max-width: 100%; display: grid; place-items: center; color: #EEE8E6; }
.player video { width: 100%; height: 100%; display: block; background: #0E0C0E; }
.player .ph { padding: 24px; text-align: center; max-width: 34rem; } .player .ph p { color: #B5ABAE; margin-top: 8px; } .player .ph a { color: #F2A541; }
.lesson { display: grid; grid-template-columns: minmax(0, 1fr) 20rem; gap: 32px; align-items: start; }
@media (max-width: 980px) { .lesson { grid-template-columns: minmax(0, 1fr); } }
.side h3 { font-size: 1rem; font-family: var(--sans); font-weight: 600; padding: 14px 16px; border-bottom: 1px solid var(--rule); }
.side .rows li:first-child { border-top: 0; } .side .row-link { padding: 9px 16px; grid-template-columns: 1.4rem minmax(0, 1fr) auto; font-size: .9rem; min-height: 44px; }
.side .row-link[aria-current="page"] { background: var(--alta-tint); font-weight: 600; }

/* reader */
.reader { max-width: 44rem; margin-inline: auto; }
.reader .prose { font-family: var(--serif); font-size: 1.14rem; line-height: 1.7; }
.reader .prose[lang="bn"] { font-family: var(--bn); font-size: 1.08rem; line-height: 1.95; }
.prose h2 { font-size: 1.45rem; margin: 2.2rem 0 .6rem; } .prose p + p { margin-top: 1rem; } .prose ul { padding-left: 1.2rem; margin: .8rem 0; } .prose li + li { margin-top: .35rem; }
.prose .tw { margin: 1.2rem 0; font-family: var(--sans); } .prose table { font-size: .92rem; }
.prose .key { font-family: var(--sans); font-size: .95rem; border: 1px solid var(--alta-line); background: var(--alta-tint); border-radius: 8px; padding: 14px 18px; margin: 1.4rem 0; }
.seg { display: inline-flex; border: 1px solid var(--rule-2); border-radius: 6px; overflow: hidden; }
.seg button { border: 0; background: transparent; padding: 0 14px; min-height: 38px; cursor: pointer; font-weight: 500; font-size: .9rem; }
.seg button + button { border-left: 1px solid var(--rule-2); }
.seg button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }

/* exam */
.exam-top { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 20; background: var(--paper); border-bottom: 1px solid var(--rule); }
.exam-top .wrap { display: flex; gap: 12px 20px; align-items: center; min-height: 60px; flex-wrap: wrap; padding-block: 8px; }
.exam-top .t { font-family: var(--serif); font-weight: 600; min-width: 0; flex: 1 1 12rem; line-height: 1.25; } .exam-top .t small { display: block; font: 400 .8125rem var(--sans); color: var(--ink-3); }
.timer { font-family: var(--serif); font-size: 1.5rem; font-weight: 600; padding: 2px 12px; border: 1px solid var(--rule-2); border-radius: 6px; min-width: 6.2rem; text-align: center; }
.timer.low { color: var(--alta); border-color: var(--alta); background: var(--alta-tint); }
.exam { display: grid; grid-template-columns: minmax(0, 1fr) 19rem; gap: 28px; padding-block: 24px 48px; align-items: start; }
@media (max-width: 940px) { .exam { grid-template-columns: minmax(0, 1fr); } }
.qhead { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; align-items: baseline; padding-bottom: 12px; border-bottom: 1px solid var(--rule); color: var(--ink-2); font-size: .9rem; }
.qhead b { font-family: var(--serif); font-size: 1.15rem; color: var(--ink); }
.qtext { font-family: var(--serif); font-size: 1.25rem; line-height: 1.5; margin: 22px 0 18px; max-width: 60ch; }
.opts { display: grid; gap: 10px; max-width: 44rem; margin: 0; padding: 0; border: 0; }
.opt { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 14px; align-items: center; padding: 12px 16px; border: 1px solid var(--rule-2); border-radius: 8px; cursor: pointer; min-height: 52px; }
.opt:hover { border-color: var(--ink-3); background: var(--paper-2); }
.opt input { position: absolute; opacity: 0; pointer-events: none; }
.opt .b { width: 30px; height: 30px; border-radius: 50%; border: 1.5px solid var(--alta-line); background: var(--alta-tint); color: var(--alta); display: grid; place-items: center; font-weight: 600; font-size: .875rem; }
.opt:has(input:checked) { border-color: var(--alta); background: var(--alta-tint); } .opt:has(input:checked) .b { background: var(--alta); border-color: var(--alta); color: var(--on-alta); }
.opt:has(input:focus-visible) { outline: 2px solid var(--alta); outline-offset: 2px; }
.qnav { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; padding-top: 18px; border-top: 1px solid var(--rule); }
.qnav .end { margin-left: auto; }
.pal h3 { font: 600 .95rem var(--sans); } .pal .sect { margin-top: 14px; } .pal .sect p { font-size: .78rem; color: var(--ink-3); margin-bottom: 6px; }
.pg { display: grid; grid-template-columns: repeat(auto-fill, minmax(32px, 1fr)); gap: 6px; }
.pb { width: 100%; aspect-ratio: 1; min-height: 32px; border-radius: 50%; border: 1.5px solid var(--alta-line); background: var(--paper); color: var(--ink-2); font-size: .75rem; font-weight: 600; cursor: pointer; padding: 0; position: relative; }
.pb.seen { background: var(--alta-tint); color: var(--alta); }
.pb.ans { background: var(--alta); border-color: var(--alta); color: var(--on-alta); }
.pb.mrk { border-color: var(--marigold); background: var(--marigold); color: #1D1A1F; }
.pb.mrk.ans::after { content: ""; position: absolute; right: -2px; bottom: -2px; width: 10px; height: 10px; border-radius: 50%; background: var(--alta); border: 2px solid var(--paper); }
.pb.cur { box-shadow: 0 0 0 2px var(--paper), 0 0 0 4px var(--ink); }
.legend { list-style: none; padding: 0; margin: 16px 0 0; display: grid; grid-template-columns: 1fr 1fr; gap: 6px 10px; font-size: .78rem; color: var(--ink-2); }
.legend li { display: flex; gap: 6px; align-items: center; } .legend .pb { width: 16px; min-height: 16px; flex: none; cursor: default; }
details.palwrap > summary { display: none; }
@media (max-width: 940px) { .pal h3 { display: none; } details.palwrap > summary { display: flex; justify-content: space-between; cursor: pointer; font-weight: 600; padding: 4px 0 12px; } }
.confirm { border: 1px solid var(--alta); border-radius: 10px; padding: 20px; background: var(--alta-tint); margin-top: 20px; }
.confirm dl { display: grid; grid-template-columns: auto 1fr; gap: 4px 16px; margin: 12px 0 16px; } .confirm dd { margin: 0; font-weight: 600; }

/* result */
.score { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 16px 40px; align-items: center; }
.score .big { font-family: var(--serif); font-size: clamp(3rem, 2rem + 5vw, 5rem); font-weight: 600; line-height: 1; letter-spacing: -.03em; } .score .big small { font-size: .35em; color: var(--ink-3); font-weight: 400; letter-spacing: 0; }
.score dl { display: grid; grid-template-columns: repeat(4, auto); gap: 4px 28px; margin: 0; justify-content: start; } .score dt { font-size: .78rem; color: var(--ink-3); text-transform: uppercase; letter-spacing: .06em; grid-row: 1; } .score dd { margin: 0; font-weight: 600; font-size: 1.2rem; grid-row: 2; }
@media (max-width: 640px) { .score { grid-template-columns: minmax(0, 1fr); } .score dl { grid-template-columns: repeat(2, auto); } .score dt, .score dd { grid-row: auto; } }
.bar { height: 8px; border-radius: 4px; background: var(--paper-3); min-width: 80px; overflow: hidden; } .bar i { display: block; height: 100%; background: var(--alta); border-radius: 4px; }
.rev { list-style: none; margin: 0; padding: 0; } .rev > li { padding: 18px 0; border-top: 1px solid var(--rule); display: grid; grid-template-columns: 2.6rem minmax(0, 1fr); gap: 8px; }
.rev .qn { font-family: var(--serif); font-weight: 600; } .rev .q { font-family: var(--serif); font-size: 1.08rem; }
.rev ol { list-style: none; margin: 10px 0; padding: 0; display: grid; gap: 4px; font-size: .95rem; }
.rev ol li { padding: 4px 10px; border-radius: 5px; display: flex; gap: 10px; } .rev ol li.key { background: var(--ok-tint); color: var(--ok); font-weight: 600; } .rev ol li.bad { background: var(--alta-tint); color: var(--alta); text-decoration: line-through; text-decoration-thickness: 1px; }
.rev .x { font-size: .92rem; color: var(--ink-2); max-width: 64ch; }
.me { background: var(--marigold-tint); } .me > * { font-weight: 600; }

/* dashboard */
.dash { display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 32px; align-items: start; }
@media (max-width: 900px) { .dash { grid-template-columns: minmax(0, 1fr); } }
.prog { list-style: none; margin: 0; padding: 0; } .prog li { display: grid; grid-template-columns: minmax(0, 11rem) minmax(0, 1fr) auto; gap: 8px 16px; padding: 12px 0; border-top: 1px solid var(--rule); align-items: center; font-size: .92rem; }
.prog li:first-child { border-top: 0; }
@media (max-width: 560px) { .prog li { grid-template-columns: minmax(0, 1fr) auto; } .prog .bub { grid-column: 1 / -1; grid-row: 2; } }

footer.site { border-top: 2px solid var(--ink); margin-top: 40px; padding-block: 36px 48px; font-size: .9rem; color: var(--ink-2); }
footer.site .wrap { display: grid; grid-template-columns: minmax(0, 2fr) repeat(2, minmax(0, 1fr)); gap: 28px; }
footer.site img { width: 84px; height: 84px; } footer.site h3 { font: 600 .78rem var(--sans); letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 10px; }
footer.site ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; } footer.site .motto { font-family: var(--serif); font-style: italic; color: var(--ink); margin-top: 10px; }
@media (max-width: 720px) { footer.site .wrap { grid-template-columns: minmax(0, 1fr); } }
.toast { position: fixed; left: 50%; bottom: calc(20px + env(safe-area-inset-bottom, 0px)); transform: translateX(-50%); background: var(--ink); color: var(--paper); padding: 10px 16px; border-radius: 8px; font-size: .9rem; z-index: 40; box-shadow: var(--shadow); max-width: calc(100vw - 32px); }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { animation: none !important; transition: none !important; } }

/* course bar, catalogue, contents, progress */
.cbar { border-bottom: 1px solid var(--rule); background: var(--paper-2); }
.cbar .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 4px 24px; padding-block: 10px 0; }
.cbar .crumbs { margin: 0 0 10px; }
.ctabs { display: flex; gap: 4px; overflow-x: auto; max-width: 100%; scrollbar-width: none; }
.ctabs a { padding: 8px 12px 12px; text-decoration: none; color: var(--ink-2); font-weight: 500; font-size: .95rem; white-space: nowrap; border-bottom: 2px solid transparent; }
.ctabs a:hover { color: var(--ink); }
.ctabs a[aria-current="page"] { color: var(--alta); border-bottom-color: var(--alta); }
.course { display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 28px 48px; border: 1px solid var(--rule); border-top: 2px solid var(--ink); border-radius: 0 0 10px 10px; padding: 28px; background: var(--paper); }
.course h2 a { color: var(--ink); text-decoration: none; } .course h2 a:hover { color: var(--alta); text-decoration: underline; }
.course dl { margin: 0; display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 10px 18px; align-content: start; font-size: .95rem; }
.course dt { color: var(--ink-3); } .course dd { margin: 0; }
@media (max-width: 820px) { .course { grid-template-columns: minmax(0, 1fr); padding: 20px; } }
.toc { margin: 0; padding-left: 2.2rem; columns: 2; column-gap: 32px; } .toc li { break-inside: avoid; padding: 2px 0; } .toc li::marker { color: var(--ink-3); font-size: .875rem; }
@media (max-width: 900px) { .toc { columns: 1; } }
details.lyr > summary { cursor: pointer; list-style: none; } details.lyr > summary::-webkit-details-marker { display: none; }
details.lyr > summary:hover { background: var(--paper-3); }
.chev { width: 14px; height: 14px; flex: none; transition: transform .15s; } details[open] > summary .chev { transform: rotate(90deg); }
.obar { position: relative; height: 14px; border-radius: 7px; background: var(--alta-tint); border: 1.5px solid var(--alta-line); margin: 14px 0 12px; }
.obar i { display: block; height: 100%; background: var(--alta); border-radius: 6px; }
.obar span { position: absolute; top: -5px; bottom: -5px; width: 2px; background: var(--marigold); }
.sec-head + .jump { margin: 0 0 28px; }

/* featured course band and the overview letter */
.feat { background: var(--band); color: var(--band-ink); padding-block: clamp(36px, 5vw, 60px); }
.feat-in { display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: clamp(24px, 5vw, 64px); align-items: start; }
@media (max-width: 900px) { .feat-in { grid-template-columns: minmax(0, 1fr); } }
.feat h2 { font-size: clamp(1.9rem, 1.2rem + 2.6vw, 2.9rem); color: var(--band-ink); }
.feat-k { font-size: .875rem; color: var(--band-soft); display: flex; flex-wrap: wrap; gap: 8px 12px; align-items: center; }
.feat-k .tag { background: #F2A541; border-color: #F2A541; color: #1D1A1F; }
.feat-l { font-size: 1.1rem; color: var(--band-soft); max-width: 54ch; }
.feat dl { margin: 0; display: grid; grid-template-columns: auto minmax(0, 1fr); border-top: 1px solid var(--band-line); }
.feat dt, .feat dd { margin: 0; padding: 10px 0; border-bottom: 1px solid var(--band-line); }
.feat dt { color: var(--band-soft); font-size: .875rem; padding-right: 20px; } .feat dd { font-weight: 500; }
.feat .btn.inv, .feat .btn.inv:hover { background: var(--band-ink); border-color: var(--band-ink); color: var(--band); }
.feat .btn.line { background: transparent; border-color: var(--band-line); color: var(--band-ink); } .feat .btn.line:hover { border-color: var(--band-ink); background: var(--band-hover); color: var(--band-ink); }
.feat :focus-visible { outline-color: #F2A541; }
.feat-n { margin-top: 28px; font-size: .875rem; color: var(--band-soft); } .feat-n a { color: var(--band-ink); }
.feat + .sec { border-top: 0; }
.letter { font-family: var(--serif); font-size: 1.1rem; line-height: 1.7; max-width: 62ch; } .letter p + p { margin-top: 1rem; }
.letter .sign { font-style: italic; margin-top: 1.4rem; } .letter .sign b { font-style: normal; color: var(--alta); }

.feat { position: relative; overflow: hidden; } .feat .wrap { position: relative; }
.alpona { position: absolute; right: -150px; bottom: -210px; width: 620px; height: 620px; color: var(--band-ink); opacity: .13; pointer-events: none; }
@media (max-width: 900px) { .alpona { right: -260px; bottom: -300px; opacity: .09; } }
footer.site { position: relative; overflow: hidden; } footer.site .alpona { color: var(--alta); opacity: .07; right: -220px; bottom: -330px; }
/* hours by layer */
.lbar { display: flex; height: 44px; border-radius: 6px; overflow: hidden; border: 1px solid var(--rule-2); margin-bottom: 10px; }
.lbar span { display: grid; place-items: center; font-size: .8125rem; font-weight: 600; min-width: 0; white-space: nowrap; overflow: hidden; }
.lbar .o { background: var(--alta); color: var(--on-alta); } .lbar .f { background: var(--alta-line); color: var(--ink); } .lbar .p2 { background: var(--marigold); color: #1D1A1F; } .lbar .p3 { background: var(--marigold-tint); color: var(--ink); }
.lkey { list-style: none; margin: 0 0 22px; padding: 0; display: flex; flex-wrap: wrap; gap: 6px 22px; font-size: .875rem; color: var(--ink-2); }
.lkey li { display: flex; align-items: center; gap: 7px; } .lkey i { width: 12px; height: 12px; border-radius: 3px; display: block; border: 1px solid var(--rule-2); }
.terms { border: 1px solid var(--rule-2); border-radius: 8px; padding: 12px 16px; margin-top: 14px; font-size: .92rem; } .terms b { color: var(--alta); }

/* ---------- skins: colour schemes switched from the demo strip ---------- */
:root[data-skin="navy"] { --alta: #1B3A6B; --alta-strong: #122A52; --alta-tint: #E4EAF4; --alta-line: #9DB0CF; --on-alta: #F7F9FD; --paper: #FCFCFD; --paper-2: #F1F3F7; --paper-3: #E6E9F0; --rule: #D5DAE3; --rule-2: #BCC4D2; --ink: #171B24; --ink-2: #505867; --ink-3: #7A8394; --band: #14284B; --band-ink: #F7F9FD; --band-soft: #C9D4E8; --band-line: #3E5687; --band-hover: #0E1D38; }
:root[data-skin="forest"] { --alta: #1F5A41; --alta-strong: #164430; --alta-tint: #E1EFE7; --alta-line: #9CC4AE; --on-alta: #F6FBF8; --paper: #FCFCFA; --paper-2: #F2F4EF; --paper-3: #E7EAE2; --rule: #D7DCD2; --rule-2: #BEC6B8; --ink: #181C19; --ink-2: #525A54; --ink-3: #7B847D; --band: #173F2E; --band-ink: #F6FBF8; --band-soft: #C7DED1; --band-line: #3F6F58; --band-hover: #0F2E21; }
:root[data-skin="saffron"] { --alta: #B4470C; --alta-strong: #8F3608; --alta-tint: #FBE9DC; --alta-line: #E5B08C; --on-alta: #FFF9F4; --marigold: #F6D365; --marigold-tint: #FBF0C9; --marigold-ink: #6B5200; --paper: #FDFCFA; --paper-2: #F5F2EE; --paper-3: #EBE6E0; --band: #1D1A1F; --band-ink: #FDFCFA; --band-soft: #CFC8CC; --band-line: #4A4348; --band-hover: #000000; }
@media (prefers-color-scheme: dark) {
  :root[data-skin="navy"]:not([data-theme="light"]) { --alta: #8FB0EA; --alta-strong: #B3C9F2; --alta-tint: #1A2740; --alta-line: #3A5080; --on-alta: #0B1220; --paper: #12151B; --paper-2: #1A1E26; --paper-3: #242A34; --rule: #2C3340; --rule-2: #414B5C; --ink: #E8ECF3; --ink-2: #AAB3C2; --ink-3: #818B9B; }
  :root[data-skin="forest"]:not([data-theme="light"]) { --alta: #7CCBA0; --alta-strong: #A3DDBD; --alta-tint: #17322A; --alta-line: #2F6049; --on-alta: #0C1711; --paper: #121512; --paper-2: #1A1F1B; --paper-3: #252B26; --rule: #2D352F; --rule-2: #424C45; --ink: #E9EEEA; --ink-2: #ABB5AE; --ink-3: #828C85; }
  :root[data-skin="saffron"]:not([data-theme="light"]) { --alta: #F0935A; --alta-strong: #F6B086; --alta-tint: #3A2114; --alta-line: #7A4424; --on-alta: #1B0F07; --marigold: #F6D365; --marigold-tint: #3D3310; --marigold-ink: #F3DB8A; --paper: #161316; --paper-2: #1F1B1F; --paper-3: #2A2529; --band: #2A2529; --band-line: #5A5156; --band-hover: #3A3338; }
}
:root[data-skin="navy"][data-theme="dark"] { --alta: #8FB0EA; --alta-strong: #B3C9F2; --alta-tint: #1A2740; --alta-line: #3A5080; --on-alta: #0B1220; --paper: #12151B; --paper-2: #1A1E26; --paper-3: #242A34; --rule: #2C3340; --rule-2: #414B5C; --ink: #E8ECF3; --ink-2: #AAB3C2; --ink-3: #818B9B; }
:root[data-skin="forest"][data-theme="dark"] { --alta: #7CCBA0; --alta-strong: #A3DDBD; --alta-tint: #17322A; --alta-line: #2F6049; --on-alta: #0C1711; --paper: #121512; --paper-2: #1A1F1B; --paper-3: #252B26; --rule: #2D352F; --rule-2: #424C45; --ink: #E9EEEA; --ink-2: #ABB5AE; --ink-3: #828C85; }
:root[data-skin="saffron"][data-theme="dark"] { --alta: #F0935A; --alta-strong: #F6B086; --alta-tint: #3A2114; --alta-line: #7A4424; --on-alta: #1B0F07; --marigold: #F6D365; --marigold-tint: #3D3310; --marigold-ink: #F3DB8A; --paper: #161316; --paper-2: #1F1B1F; --paper-3: #2A2529; --band: #2A2529; --band-line: #5A5156; --band-hover: #3A3338; }

/* social and share chips */
.soc { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.chip { display: inline-flex; align-items: center; min-height: 36px; padding: 0 14px; border: 1px solid var(--rule-2); border-radius: 999px; background: var(--paper); color: var(--ink); font: 500 .875rem var(--sans); text-decoration: none; cursor: pointer; }
.chip:hover { border-color: var(--alta); color: var(--alta); }
footer.site .wrap { position: relative; }

/* photographs */
.feat-ph { position: absolute; inset: 0 0 0 38%; background: url(../media/photos/steel.jpg) 60% center / cover no-repeat; filter: grayscale(1) contrast(1.15); mix-blend-mode: luminosity; opacity: .42; -webkit-mask-image: linear-gradient(90deg, transparent, #000 45%); mask-image: linear-gradient(90deg, transparent, #000 45%); }
@media (max-width: 900px) { .feat-ph { inset: 0; opacity: .2; -webkit-mask-image: linear-gradient(180deg, transparent 30%, #000); mask-image: linear-gradient(180deg, transparent 30%, #000); } }
.feat dl { background: color-mix(in srgb, var(--band) 78%, transparent); padding: 0 16px; border-radius: 8px; border-top: 0; } .feat dl > :nth-last-child(-n+2) { border-bottom: 0; }
.feat-c { margin-top: 6px; font-size: .78rem; color: var(--band-soft); } .feat-c a { color: var(--band-ink); }
.mosaic { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 14px; }
.ph { margin: 0; position: relative; border-radius: 10px; overflow: hidden; grid-column: span 2; background: var(--paper-3); }
.ph.wide { grid-column: span 3; }
.ph img { display: block; width: 100%; height: 300px; object-fit: cover; }
.ph figcaption { position: absolute; left: 0; right: 0; bottom: 0; padding: 40px 16px 12px; color: #FFF8F3; background: linear-gradient(transparent, rgba(20, 8, 6, .82)); display: grid; gap: 1px; }
.ph figcaption b { font-family: var(--serif); font-size: 1.05rem; font-weight: 600; } .ph figcaption span { font-size: .8125rem; color: #F1DDD9; }
@media (max-width: 760px) { .mosaic { grid-template-columns: minmax(0, 1fr); } .ph, .ph.wide { grid-column: auto; } .ph img { height: 220px; } }

/* home: the Hooghly at dawn */
:root { --art-dim: 1; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --art-dim: .5; } }
:root[data-theme="dark"] { --art-dim: .5; }
.hero.art { position: relative; overflow: hidden; padding-block: clamp(64px, 10vw, 132px) clamp(56px, 8vw, 104px); }
.hero-art { position: absolute; inset: 0; background: url(../media/art/hooghly-dawn.jpg) right center / cover no-repeat; filter: brightness(var(--art-dim)); }
.hero-art::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, var(--paper) 26%, transparent 66%), linear-gradient(0deg, var(--paper), transparent 28%); }
.hero-t { position: relative; max-width: 35rem; }
.hero.art + .feat { margin-top: 0; }
@media (max-width: 760px) {
  .hero.art { padding-top: 0; }
  .hero-art { position: relative; height: 200px; background-position: 78% center; margin-bottom: 20px; }
  .hero-art::after { background: linear-gradient(0deg, var(--paper), transparent 45%); }
}

/* on the live server the demo strip is not shown */
.live .demo { display: none; }