/* A Level Math Revision — shared stylesheet */
:root {
    --ink: #0b1a33;
    --ink-soft: #35476a;
    --muted: #6b7a99;
    --line: #d6dfec;
    --page: #f4f7fc;
    --card: #ffffff;
    --linear: #9a1b1b;      /* UK Linear A Level */
    --linear-soft: rgba(154,27,27,0.09);
    --modular: #0e7c86;     /* International (modular) */
    --modular-soft: rgba(14,124,134,0.10);
    --accent: #f57f17;
    --radius: 16px;
    --shadow: 0 12px 30px rgba(11,26,51,0.10);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
    font-family: 'Inter', -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(180deg, #eef3fb 0%, #f8fafd 60%, #fff 100%);
    color: var(--ink);
    line-height: 1.6;
    min-height: 100vh;
}
a { color: var(--linear); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Top nav */
header.topbar {
    display: flex; align-items: center; justify-content: space-between;
    max-width: 1180px; margin: 0 auto; padding: 20px 24px 8px;
    gap: 14px; flex-wrap: wrap;
}
header.topbar .brand { display: flex; align-items: center; gap: 12px; font-weight: 800; color: var(--ink); font-size: 1.02rem; }
header.topbar .brand img { width: 34px; height: 34px; }
header.topbar .brand small { display: block; font-size: 0.68rem; color: var(--muted); font-weight: 600; letter-spacing: 2px; text-transform: uppercase; margin-top: 2px; }
header.topbar nav.spec-switch { display: flex; gap: 6px; background: #eef3fb; padding: 4px; border-radius: 999px; }
header.topbar nav.spec-switch a { padding: 6px 14px; border-radius: 999px; font-weight: 700; font-size: 0.82rem; color: var(--ink-soft); }
header.topbar nav.spec-switch a.active-linear   { background: var(--linear);  color: #fff; }
header.topbar nav.spec-switch a.active-modular  { background: var(--modular); color: #fff; }
header.topbar .mail { color: var(--linear); font-weight: 700; font-size: 0.85rem; }

/* Hero */
section.hero { max-width: 1180px; margin: 0 auto; padding: 40px 24px 20px; text-align: center; }
.eyebrow { display: inline-block; padding: 6px 14px; border-radius: 999px; font-weight: 800; font-size: 0.72rem; letter-spacing: 2px; text-transform: uppercase; margin-bottom: 16px; background: var(--linear-soft); color: var(--linear); }
.eyebrow.modular { background: var(--modular-soft); color: var(--modular); }
h1 { font-size: clamp(1.9rem, 4.4vw, 3rem); line-height: 1.12; margin: 0 0 14px; letter-spacing: -0.6px; color: var(--ink); }
h1 em { font-style: normal; }
.lede { font-size: clamp(1rem, 1.4vw, 1.12rem); color: var(--ink-soft); max-width: 720px; margin: 0 auto; }

/* Two-door layout (root landing) */
section.doors { max-width: 1100px; margin: 0 auto; padding: 40px 24px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
.door {
    position: relative; display: flex; flex-direction: column;
    background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
    padding: 32px 30px 26px; color: var(--ink); text-decoration: none;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
    overflow: hidden; min-height: 320px;
}
.door::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 5px; background: var(--linear); transition: height 0.25s ease; }
.door.modular::before { background: var(--modular); }
.door:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: transparent; text-decoration: none; }
.door:hover::before { height: 9px; }
.door .badge { position: absolute; top: 22px; right: 22px; font-size: 0.66rem; font-weight: 800; letter-spacing: 1.2px; text-transform: uppercase; padding: 5px 10px; border-radius: 999px; background: #fff2d6; color: #7a4e00; }
.door .logo-wrap { width: 76px; height: 76px; border-radius: 16px; display: flex; align-items: center; justify-content: center; background: var(--linear-soft); color: var(--linear); margin-bottom: 20px; }
.door.modular .logo-wrap { background: var(--modular-soft); color: var(--modular); }
.door .logo-wrap svg { width: 42px; height: 42px; }
.door h2 { margin: 0 0 6px; font-size: 1.32rem; color: var(--ink); letter-spacing: -0.3px; }
.door .subtitle { font-size: 0.82rem; color: var(--muted); font-weight: 700; letter-spacing: 0.5px; margin: 0 0 14px; text-transform: uppercase; }
.door p.copy { margin: 0 0 22px; color: var(--ink-soft); font-size: 0.95rem; }
.door .foot { margin-top: auto; display: inline-flex; align-items: center; gap: 8px; font-weight: 800; font-size: 0.95rem; color: var(--linear); }
.door.modular .foot { color: var(--modular); }
.door:hover .foot .arrow { transform: translateX(4px); }
.door .foot .arrow { transition: transform 0.2s ease; }

/* Spec pages */
section.spec-body { max-width: 1180px; margin: 0 auto; padding: 20px 24px 40px; }
.spec-header {
    padding: 30px 32px; border-radius: var(--radius); border: 1px solid var(--line); background: var(--card);
    margin-bottom: 30px; display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: end;
}
.spec-header.linear   { border-top: 5px solid var(--linear); }
.spec-header.modular  { border-top: 5px solid var(--modular); }
.spec-header h1 { margin: 0 0 6px; font-size: 1.8rem; }
.spec-header p { margin: 0; color: var(--ink-soft); font-size: 0.98rem; }
.spec-header .boards { display: flex; gap: 8px; flex-wrap: wrap; }
.spec-header .board-pill { background: var(--linear-soft); color: var(--linear); padding: 6px 12px; border-radius: 999px; font-weight: 700; font-size: 0.82rem; }
.spec-header.modular .board-pill { background: var(--modular-soft); color: var(--modular); }

/* Area sections + topic grid */
section.area { margin: 30px 0 10px; }
section.area h2 { font-size: 1.35rem; margin: 0 0 6px; color: var(--ink); letter-spacing: -0.2px; }
section.area .area-sub { color: var(--muted); font-size: 0.92rem; margin: 0 0 18px; }
.topic-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.topic-card {
    display: flex; flex-direction: column;
    background: var(--card); border: 1px solid var(--line); border-radius: 12px;
    padding: 18px 20px; color: var(--ink); text-decoration: none;
    transition: transform 0.2s ease, border-color 0.2s ease;
}
.topic-card:hover { transform: translateY(-2px); border-color: var(--linear); text-decoration: none; }
body[data-spec="modular"] .topic-card:hover { border-color: var(--modular); }
.topic-card h3 { margin: 0 0 4px; font-size: 1rem; color: var(--ink); }
.topic-card .paper-tag { font-size: 0.76rem; color: var(--muted); font-weight: 600; margin: 0; letter-spacing: 0.2px; }
.topic-card .empty-pill { align-self: flex-start; margin-top: 10px; background: #f4f7fc; color: var(--muted); padding: 3px 9px; border-radius: 999px; font-size: 0.7rem; font-weight: 800; text-transform: uppercase; letter-spacing: 1px; }

/* Unit cards (modular page) */
.unit-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; margin: 14px 0 28px; }
.unit-card { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; }
.unit-card h4 { margin: 0 0 4px; color: var(--modular); font-size: 1rem; }
.unit-card .unit-topics { list-style: none; padding: 0; margin: 8px 0 0; font-size: 0.86rem; color: var(--ink-soft); }
.unit-card .unit-topics li { padding: 3px 0; }
.unit-card .unit-topics li a { color: var(--ink); }
.unit-card .unit-topics li a:hover { color: var(--modular); }

/* Topic detail page */
.topic-wrap { max-width: 900px; margin: 0 auto; padding: 20px 24px 40px; }
.topic-crumb { color: var(--muted); font-size: 0.85rem; margin-bottom: 14px; }
.topic-crumb a { color: var(--ink-soft); font-weight: 600; }
.topic-title-row { display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 12px; margin-bottom: 10px; }
.topic-title-row h1 { margin: 0; font-size: 2rem; }
.topic-area-pill { background: var(--linear-soft); color: var(--linear); padding: 5px 12px; border-radius: 999px; font-size: 0.78rem; font-weight: 800; text-transform: uppercase; letter-spacing: 1px; }
body[data-spec="modular"] .topic-area-pill { background: var(--modular-soft); color: var(--modular); }

.mapping-panel { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px 26px; margin: 22px 0; }
.mapping-panel h2 { margin: 0 0 14px; font-size: 1.05rem; color: var(--ink); }
.mapping-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.mapping-cell { background: #f4f7fc; padding: 14px 16px; border-radius: 12px; }
.mapping-cell.linear   { border-left: 4px solid var(--linear); }
.mapping-cell.modular  { border-left: 4px solid var(--modular); }
.mapping-cell h3 { margin: 0 0 6px; font-size: 0.84rem; text-transform: uppercase; letter-spacing: 1.4px; color: var(--muted); }
.mapping-cell .val { color: var(--ink); font-weight: 700; font-size: 0.95rem; }
.mapping-cell .val small { display: block; color: var(--ink-soft); font-weight: 500; margin-top: 4px; font-size: 0.85rem; }

.section-placeholder {
    background: repeating-linear-gradient(45deg, #fbfcfe, #fbfcfe 10px, #f4f7fc 10px, #f4f7fc 20px);
    border: 1px dashed var(--line);
    border-radius: var(--radius); padding: 32px 28px; margin: 20px 0;
    text-align: center; color: var(--muted);
}
.section-placeholder h3 { color: var(--ink); margin: 0 0 6px; font-size: 1.1rem; }
.section-placeholder p { margin: 0; font-size: 0.94rem; }

/* Footer */
footer.site-foot { text-align: center; padding: 30px 24px 40px; color: var(--muted); font-size: 0.85rem; }
footer.site-foot a { color: var(--linear); font-weight: 600; }
footer.site-foot .foot-links { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; margin-bottom: 10px; }

@media (max-width: 860px) {
    section.doors { grid-template-columns: 1fr; }
    .spec-header { grid-template-columns: 1fr; }
    .mapping-grid { grid-template-columns: 1fr; }
    header.topbar { flex-wrap: wrap; }
    header.topbar .brand small { display: none; }
}

/* =====================================================================
 * FRAMEWORK ADDITIONS (Bucket 1+2+3 — reused IB features)
 * ===================================================================== */

/* Shared padding to accommodate injected nav on account/bookmarks/topic pages */
body:has(nav.topnav) { padding-top: 6px; }
.hidden { display: none !important; }

/* --- topic.html engine additions --- */
.topic-util-row { display: flex; gap: 10px; margin: 6px 0 18px; flex-wrap: wrap; }
.topic-util {
    background: #fff; border: 1px solid var(--line); color: var(--ink-soft);
    padding: 8px 14px; border-radius: 999px; font-weight: 700; font-size: 0.82rem;
    cursor: pointer; transition: background 0.2s, border-color 0.2s;
}
.topic-util:hover { border-color: var(--linear); color: var(--linear); background: #fdf2f2; }
body[data-spec="modular"] .topic-util:hover { border-color: var(--modular); color: var(--modular); background: #eef8f8; }
.topic-util.bookmarked { background: #fff2d6; border-color: #7a4e00; color: #7a4e00; }

.section-h { font-size: 1.3rem; margin: 28px 0 14px; color: var(--ink); letter-spacing: -0.2px; }

/* Question card */
.q-card {
    background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
    padding: 24px 26px; margin-bottom: 18px; box-shadow: 0 2px 4px rgba(11,26,51,0.03);
}
.q-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
.q-idx { background: var(--linear-soft); color: var(--linear); padding: 4px 12px; border-radius: 999px; font-weight: 800; font-size: 0.85rem; }
body[data-spec="modular"] .q-idx { background: var(--modular-soft); color: var(--modular); }
.q-marks { color: var(--muted); font-size: 0.82rem; font-weight: 700; }
.q-prompt { font-size: 1.02rem; color: var(--ink); margin-bottom: 16px; line-height: 1.6; }
.q-workings label { display: block; font-size: 0.78rem; font-weight: 700; color: var(--muted); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 6px; }
.q-input { width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px; font-family: inherit; font-size: 0.95rem; resize: vertical; min-height: 120px; }
.q-input:focus { outline: 2px solid var(--linear); outline-offset: -1px; border-color: var(--linear); }
body[data-spec="modular"] .q-input:focus { outline-color: var(--modular); border-color: var(--modular); }
.q-photo { margin-top: 10px; display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.q-photo-label {
    display: inline-flex; align-items: center; gap: 6px; background: #f4f7fc;
    border: 1px dashed var(--line); padding: 8px 14px; border-radius: 10px;
    font-size: 0.86rem; font-weight: 700; color: var(--ink-soft); cursor: pointer;
}
.q-photo-label:hover { background: #eef3fb; border-color: var(--linear); }
.q-photo input[type=file] { display: none; }
.q-photo-name { font-size: 0.82rem; color: var(--muted); }
.q-actions { display: flex; gap: 10px; margin-top: 16px; flex-wrap: wrap; }
.q-grade-btn, .q-scheme-btn {
    padding: 10px 20px; border-radius: 10px; font-weight: 700; font-size: 0.92rem; cursor: pointer; border: none;
}
.q-grade-btn { background: var(--linear); color: #fff; }
body[data-spec="modular"] .q-grade-btn { background: var(--modular); }
.q-grade-btn:hover:not(:disabled) { transform: translateY(-1px); filter: brightness(1.08); }
.q-grade-btn:disabled { opacity: 0.6; cursor: not-allowed; }
.q-scheme-btn { background: transparent; color: var(--ink-soft); border: 1px solid var(--line); }
.q-scheme-btn:hover { border-color: var(--ink-soft); color: var(--ink); }
.q-scheme { margin-top: 16px; padding: 16px 18px; background: #f4f7fc; border-left: 4px solid var(--muted); border-radius: 8px; font-size: 0.95rem; color: var(--ink-soft); }
.q-feedback { margin-top: 12px; }
.q-feedback:empty { display: none; }
.q-fb-loading { color: var(--muted); font-style: italic; padding: 10px 0; }
.q-fb-err { color: #7f1d1d; background: #fef2f2; border: 1px solid #fecaca; padding: 12px 14px; border-radius: 10px; }
.q-fb-ok  { background: #ecfdf5; border: 1px solid #a7f3d0; padding: 14px 16px; border-radius: 10px; }
.q-fb-score { font-size: 1.1rem; font-weight: 800; color: #166534; margin-bottom: 6px; }
.q-fb-body  { color: var(--ink); font-size: 0.95rem; }

/* --- account.html + bookmarks.html --- */
.acct-wrap { max-width: 980px; margin: 0 auto; padding: 20px 24px 60px; }
.acct-header { margin-bottom: 24px; }
.acct-header h1 { margin: 0 0 6px; font-size: 2rem; letter-spacing: -0.4px; }
.signed-out-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 30px 28px; text-align: center; }
.signed-out-card p { margin: 0 0 18px; color: var(--ink-soft); }
.btn-primary { background: var(--linear); color: #fff; border: none; padding: 12px 26px; border-radius: 10px; font-weight: 700; font-size: 0.95rem; cursor: pointer; }
.btn-primary:hover { filter: brightness(1.08); }
.btn-secondary { background: transparent; color: var(--muted); border: 1px solid var(--line); padding: 10px 22px; border-radius: 10px; font-weight: 700; font-size: 0.9rem; cursor: pointer; }
.btn-secondary:hover { color: var(--ink); border-color: var(--ink-soft); }

.acct-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 16px 0 8px; }
.acct-tile { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 20px 22px; }
.acct-tile h3 { margin: 0 0 8px; font-size: 0.82rem; color: var(--muted); text-transform: uppercase; letter-spacing: 1.2px; font-weight: 800; }
.tile-big { font-size: 2.2rem; font-weight: 800; color: var(--linear); letter-spacing: -0.5px; margin-bottom: 4px; }
.acct-tile:nth-child(2) .tile-big { color: var(--modular); }
.acct-tile:nth-child(3) .tile-big { color: var(--ink); }
.tile-sub { color: var(--muted); font-size: 0.82rem; margin: 0; }

.acct-section { margin-top: 32px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 24px 26px; }
.acct-section h2 { margin: 0 0 6px; font-size: 1.15rem; letter-spacing: -0.2px; }
.acct-hint { color: var(--muted); font-size: 0.9rem; margin: 0 0 14px; }

.weak-row { display: grid; grid-template-columns: 1fr 200px 60px; align-items: center; gap: 14px; padding: 12px 16px; background: #fdf2f2; border-radius: 10px; margin-bottom: 8px; text-decoration: none; color: var(--ink); }
.weak-row:hover { background: #fce6e6; }
.weak-name { font-weight: 700; }
.weak-bar { height: 10px; background: #f4f7fc; border-radius: 999px; overflow: hidden; }
.weak-bar span { display: block; height: 100%; background: linear-gradient(90deg, var(--linear), #e57373); }
.weak-pct { font-weight: 800; color: var(--linear); text-align: right; font-variant-numeric: tabular-nums; }

.recent-ul { list-style: none; padding: 0; margin: 0; }
.recent-ul li { display: flex; align-items: center; gap: 10px; padding: 10px 0; border-bottom: 1px solid var(--line); font-size: 0.92rem; }
.recent-ul li:last-child { border-bottom: 0; }
.recent-ul li a { color: var(--ink); font-weight: 600; text-decoration: none; flex: 1; }
.recent-ul li a:hover { color: var(--linear); }
.pill-score { background: #ecfdf5; color: #166534; padding: 3px 10px; border-radius: 999px; font-weight: 800; font-size: 0.8rem; font-variant-numeric: tabular-nums; }
.pill-when { color: var(--muted); font-size: 0.78rem; font-variant-numeric: tabular-nums; }

@media (max-width: 720px) {
    .weak-row { grid-template-columns: 1fr 40px; grid-template-areas: "name pct" "bar bar"; }
    .weak-row .weak-name { grid-area: name; }
    .weak-row .weak-pct  { grid-area: pct; }
    .weak-row .weak-bar  { grid-area: bar; }
    .q-actions { flex-direction: column; }
    .q-grade-btn, .q-scheme-btn { width: 100%; }
    .recent-ul li { flex-wrap: wrap; gap: 6px; }
}