/* StudyLoop — calm, friendly, focused. Mobile first. */
:root {
  --bg: #f5f9fb;
  --surface: #ffffff;
  --surface-2: #edf4f8;
  --border: #dce6ed;
  --text: #18242e;
  --muted: #63717d;
  --primary: #0879b9;
  --primary-2: #062a4a;
  --primary-ink: #ffffff;
  --primary-soft: #e3f1f9;
  --accent: #edab72;
  --accent-soft: #fdf0e2;
  --teal: #08a6ad;
  --good: #0f9d6b;
  --good-soft: #def5ec;
  --bad: #e11d48;
  --bad-soft: #fde7ec;
  --info: #0879b9;
  --m-new: #a9b8c4;
  --m-learning: #edab72;
  --m-familiar: #08a6ad;
  --m-mastered: #0f9d6b;
  --radius: 20px;
  --radius-sm: 12px;
  --shadow: 0 1px 2px rgba(5, 42, 74, 0.05), 0 10px 30px rgba(5, 42, 74, 0.08);
  --shadow-lg: 0 24px 70px rgba(5, 42, 74, 0.2);
  --font: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  --read: Georgia, "Iowan Old Style", "Palatino Linotype", Charter, serif;
  --nav-h: 64px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #051a2e; --surface: #0a2740; --surface-2: #0f3354; --border: #1b4266; --text: #e8f1f7; --muted: #9bb3c4;
    --primary: #3db4e8; --primary-2: #0879b9; --primary-ink: #04203a; --primary-soft: #0e3555; --accent: #edab72; --accent-soft: #3a2a18;
    --teal: #2dd4cf; --good: #34d399; --good-soft: #0d3a30; --bad: #fb7185; --bad-soft: #3d1621; --shadow: 0 1px 2px rgba(0,0,0,.3), 0 6px 20px rgba(0,0,0,.25);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #051a2e; --surface: #0a2740; --surface-2: #0f3354; --border: #1b4266; --text: #e8f1f7; --muted: #9bb3c4;
  --primary: #3db4e8; --primary-2: #0879b9; --primary-ink: #04203a; --primary-soft: #0e3555; --accent: #edab72; --accent-soft: #3a2a18;
  --teal: #2dd4cf; --good: #34d399; --good-soft: #0d3a30; --bad: #fb7185; --bad-soft: #3d1621; --shadow: 0 1px 2px rgba(0,0,0,.3), 0 6px 20px rgba(0,0,0,.25);
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.5 var(--font); -webkit-font-smoothing: antialiased; }
img, svg { display: block; max-width: 100%; }
svg[aria-hidden="true"] { width: 1.15em; height: 1.15em; flex: none; display: inline-block; vertical-align: -0.2em; }
button, input, select, textarea { font: inherit; color: inherit; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
:focus-visible { outline: 3px solid color-mix(in srgb, var(--primary) 55%, transparent); outline-offset: 2px; border-radius: 6px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ---------- shell ---------- */
.shell { min-height: 100dvh; padding-bottom: calc(var(--nav-h) + env(safe-area-inset-bottom)); }
.main { max-width: 760px; margin: 0 auto; padding: 16px 16px 40px; }
.main.wide { max-width: 1040px; }
.topbar { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; gap: 10px; padding: 10px 16px; background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(10px); border-bottom: 1px solid transparent; }
.topbar.scrolled { border-bottom-color: var(--border); }
.topbar h1 { font-size: 17px; color: var(--text); margin: 0; flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: -0.02em; font-size: 18px; color: var(--text); }
.brand-mark { width: 34px; height: 34px; object-fit: contain; }
.brand-by { font-size: 11px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); text-align: center; margin: 18px 0 0; }
.brand-by b { color: var(--text); }
.chip-xp { display: inline-flex; align-items: center; gap: 6px; padding: 5px 10px; border-radius: 99px; background: var(--accent-soft); color: color-mix(in srgb, var(--accent) 70%, var(--text)); font-weight: 700; font-size: 14px; }
.chip-streak { background: #ffe9df; color: #c2410c; }
:root[data-theme="dark"] .chip-streak { background: #3b1f12; color: #fdba74; }

.tabbar { position: fixed; z-index: 30; left: 0; right: 0; bottom: 0; height: calc(var(--nav-h) + env(safe-area-inset-bottom)); padding-bottom: env(safe-area-inset-bottom); display: grid; grid-template-columns: repeat(5, 1fr); background: var(--surface); border-top: 1px solid var(--border); }
.tabbar a { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 2px; font-size: 11px; font-weight: 600; color: var(--muted); text-decoration: none; }
.tabbar a svg { width: 24px; height: 24px; }
.tabbar a.active { color: var(--primary); }
.tabbar .badge-dot { position: absolute; transform: translate(12px, -14px); min-width: 18px; height: 18px; padding: 0 5px; border-radius: 9px; background: var(--bad); color: #fff; font-size: 11px; line-height: 18px; text-align: center; }
.tabbar a > span.icon { position: relative; }

@media (min-width: 900px) {
  .shell { padding-bottom: 0; padding-left: 232px; }
  .tabbar { top: 0; right: auto; width: 232px; height: auto; grid-template-columns: 1fr; grid-auto-rows: 52px; align-content: start; padding: 72px 12px 12px; border-top: 0; border-right: 1px solid var(--border); }
  .tabbar a { flex-direction: row; justify-content: flex-start; gap: 12px; padding: 0 14px; border-radius: 12px; font-size: 15px; }
  .tabbar a.active { background: var(--primary-soft); }
  .tabbar .side-brand { position: absolute; top: 18px; left: 26px; }
  .main { padding-top: 24px; }
}
@media (max-width: 899px) { .tabbar .side-brand { display: none; } }

/* ---------- type ---------- */
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.02em; }
.page-title { font-size: 28px; margin: 6px 0 4px; }
.lead { color: var(--muted); margin: 0 0 18px; }
.section-title { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; font-size: 18px; margin: 28px 0 10px; }
.section-title small { font-size: 14px; font-weight: 600; color: var(--muted); }
.muted { color: var(--muted); }
.small { font-size: 14px; }
.tiny { font-size: 12px; }
.center { text-align: center; }

/* ---------- surfaces ---------- */
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.card + .card { margin-top: 12px; }
.card.flat { box-shadow: none; }
.card.tint { background: var(--primary-soft); border-color: transparent; }
.card.warm { background: var(--accent-soft); border-color: transparent; }
.grid { display: grid; gap: 12px; }
.grid.two { grid-template-columns: repeat(auto-fill, minmax(min(100%, 300px), 1fr)); }
.grid.stats { grid-template-columns: repeat(3, 1fr); }
.row { display: flex; align-items: center; gap: 12px; }
.row.wrap { flex-wrap: wrap; }
.row.between { justify-content: space-between; }
.stack > * + * { margin-top: 12px; }
.spacer { flex: 1; }
hr { border: 0; border-top: 1px solid var(--border); margin: 18px 0; }

/* ---------- buttons ---------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 46px; padding: 0 18px; border: 0; border-radius: 12px; background: var(--primary); color: var(--primary-ink); font-weight: 700; cursor: pointer; text-decoration: none; transition: transform .08s ease, filter .15s ease, background .15s; user-select: none; }
.btn:not(.soft):not(.ghost):not(.good):not(.danger) { background: linear-gradient(110deg, var(--primary-2), var(--primary)); box-shadow: 0 10px 24px rgba(8,121,185,.22); }
.btn:hover { filter: brightness(1.06); text-decoration: none; }
.btn:active { transform: scale(0.98); }
.btn[disabled] { opacity: .5; cursor: not-allowed; }
.btn.block { width: 100%; }
.btn.big { min-height: 56px; font-size: 18px; border-radius: 14px; }
.btn.soft { background: var(--primary-soft); color: var(--primary); }
.btn.ghost { background: transparent; color: var(--text); border: 1px solid var(--border); }
.btn.good { background: var(--good); color: #fff; }
.btn.danger { background: var(--bad-soft); color: var(--bad); }
.btn.small { min-height: 36px; padding: 0 12px; font-size: 14px; border-radius: 10px; }
.btn svg { width: 20px; height: 20px; }
.icon-btn { display: inline-grid; place-items: center; width: 40px; height: 40px; border-radius: 12px; border: 0; background: transparent; color: var(--text); cursor: pointer; }
.icon-btn:hover { background: var(--surface-2); }
.icon-btn svg { width: 22px; height: 22px; }

/* ---------- forms ---------- */
.field { display: block; margin-bottom: 14px; }
.field > span { display: block; font-weight: 600; font-size: 14px; margin-bottom: 6px; }
.input, select.input, textarea.input { width: 100%; min-height: 48px; padding: 10px 14px; border: 1.5px solid var(--border); border-radius: 12px; background: var(--surface); }
.input:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 4px var(--primary-soft); }
textarea.input { min-height: 90px; resize: vertical; }
.form-error { color: var(--bad); font-weight: 600; font-size: 14px; min-height: 20px; }
.seg { display: inline-flex; padding: 4px; background: var(--surface-2); border-radius: 12px; gap: 4px; flex-wrap: wrap; }
.seg button { border: 0; background: transparent; padding: 8px 14px; border-radius: 9px; font-weight: 600; cursor: pointer; color: var(--muted); }
.seg button.on { background: var(--surface); color: var(--text); box-shadow: var(--shadow); }

/* ---------- auth ---------- */
.auth { min-height: 100dvh; display: grid; place-items: center; padding: 24px 16px; background: radial-gradient(1200px 500px at 50% -10%, var(--primary-soft), transparent), var(--bg); }
.auth .card { width: 100%; max-width: 420px; padding: 28px 24px; }
.auth .brand { justify-content: center; font-size: 24px; margin-bottom: 6px; }
.auth .brand-mark { width: 48px; height: 48px; }
.auth h2 { text-align: center; margin: 8px 0 4px; }
.auth p.lead { text-align: center; }

/* ---------- today ---------- */
.hello { display: flex; align-items: center; gap: 14px; margin: 4px 0 16px; }
.hello h2 { margin: 0; font-size: 24px; }
.goal { display: grid; grid-template-columns: auto 1fr; gap: 16px; align-items: center; }
.ring { --p: 0; --c: var(--primary); width: 84px; height: 84px; border-radius: 50%; background: conic-gradient(var(--c) calc(var(--p) * 1%), var(--surface-2) 0); display: grid; place-items: center; position: relative; flex: none; }
.ring::before { content: ""; position: absolute; inset: 9px; border-radius: 50%; background: var(--surface); }
.ring > * { position: relative; font-weight: 800; font-size: 18px; }
.ring.small { width: 52px; height: 52px; }
.ring.small::before { inset: 6px; }
.ring.small > * { font-size: 13px; }
.ring.large { width: 140px; height: 140px; }
.ring.large::before { inset: 12px; }
.ring.large > * { font-size: 30px; }
.bar { height: 10px; background: var(--surface-2); border-radius: 99px; overflow: hidden; }
.bar > i { display: block; height: 100%; width: 0; background: var(--primary); border-radius: inherit; transition: width .5s ease; }
.bar.accent > i { background: var(--accent); }
.bar.good > i { background: var(--good); }
.stat { text-align: center; padding: 14px 8px; }
.stat b { display: block; font-size: 24px; }
.stat span { font-size: 13px; color: var(--muted); }
.plan-item { display: flex; align-items: center; gap: 14px; padding: 14px; border-radius: 14px; background: var(--surface); border: 1px solid var(--border); text-decoration: none; color: inherit; cursor: pointer; }
.plan-item + .plan-item { margin-top: 10px; }
.plan-item:hover { border-color: var(--primary); text-decoration: none; }
.plan-item .pi-icon { width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; flex: none; }
.plan-item .pi-icon svg { width: 24px; height: 24px; }
.plan-item .pi-body { flex: 1; min-width: 0; }
.plan-item .pi-body b { display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.plan-item .pi-body span { font-size: 13px; color: var(--muted); }
.pi-review { background: var(--accent-soft); color: var(--accent); }
.pi-learn { background: var(--primary-soft); color: var(--primary); }
.pi-quiz { background: var(--good-soft); color: var(--good); }
.pi-speed { background: #ffe9df; color: #ea580c; }
.exam-card { display: flex; align-items: center; gap: 16px; }
.exam-days { font-size: 40px; font-weight: 800; line-height: 1; color: var(--primary); }

/* ---------- packs ---------- */
.pack { position: relative; display: block; padding: 18px; border-radius: var(--radius); background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow); color: inherit; text-decoration: none; overflow: hidden; }
.pack:hover { text-decoration: none; border-color: var(--primary); }
.pack::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 6px; background: var(--pc, var(--primary)); }
.pack h3 { margin: 6px 0 4px; font-size: 18px; }
.pack .meta { font-size: 13px; color: var(--muted); }
.pc0 { --pc: #0879b9; } .pc1 { --pc: #08a6ad; } .pc2 { --pc: #0f9d6b; } .pc3 { --pc: #edab72; } .pc4 { --pc: #062a4a; } .pc5 { --pc: #5b8db8; }
.status-pill { display: inline-flex; align-items: center; gap: 6px; padding: 3px 10px; border-radius: 99px; font-size: 12px; font-weight: 700; background: var(--surface-2); color: var(--muted); }
.status-pill.processing { background: var(--primary-soft); color: var(--primary); }
.status-pill.failed { background: var(--bad-soft); color: var(--bad); }
.actions { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 10px; }
.action { display: flex; flex-direction: column; gap: 8px; align-items: flex-start; padding: 14px; border-radius: 14px; border: 1px solid var(--border); background: var(--surface); cursor: pointer; text-align: left; color: inherit; text-decoration: none; }
.action:hover { border-color: var(--primary); text-decoration: none; }
.action svg { width: 26px; height: 26px; color: var(--primary); }
.action b { font-size: 15px; }
.action span { font-size: 12px; color: var(--muted); }
.topic-row { display: flex; align-items: center; gap: 12px; padding: 12px 14px; border-radius: 14px; background: var(--surface); border: 1px solid var(--border); color: inherit; text-decoration: none; }
.topic-row + .topic-row { margin-top: 8px; }
.topic-row:hover { border-color: var(--primary); text-decoration: none; }
.topic-num { width: 34px; height: 34px; border-radius: 50%; display: grid; place-items: center; font-weight: 800; font-size: 14px; flex: none; background: var(--surface-2); color: var(--muted); border: 3px solid var(--mc, var(--m-new)); }
.topic-row .tr-body { flex: 1; min-width: 0; }
.topic-row .tr-body b { display: block; font-size: 15px; }
.topic-row .tr-body span { font-size: 12px; color: var(--muted); }
.mastery { display: inline-block; padding: 2px 8px; border-radius: 99px; font-size: 11px; font-weight: 800; text-transform: uppercase; letter-spacing: .04em; color: #fff; background: var(--mc); }
.m-new { --mc: var(--m-new); } .m-learning { --mc: var(--m-learning); } .m-familiar { --mc: var(--m-familiar); } .m-mastered { --mc: var(--m-mastered); }

/* ---------- upload ---------- */
.drop { display: grid; place-items: center; gap: 8px; padding: 34px 18px; border: 2px dashed var(--border); border-radius: var(--radius); background: var(--surface); text-align: center; cursor: pointer; transition: border-color .15s, background .15s; }
.drop.over, .drop:hover { border-color: var(--primary); background: var(--primary-soft); }
.drop svg { width: 46px; height: 46px; color: var(--primary); }
.file-row { display: flex; align-items: center; gap: 12px; padding: 10px 12px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface); }
.file-row + .file-row { margin-top: 8px; }
.file-row .fr-body { flex: 1; min-width: 0; }
.file-row .fr-body b { display: block; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.file-row .fr-body span { font-size: 12px; color: var(--muted); }
.file-ico { width: 38px; height: 38px; border-radius: 10px; display: grid; place-items: center; font-size: 11px; font-weight: 800; background: var(--surface-2); color: var(--muted); flex: none; }
.building { text-align: center; padding: 30px 10px; }
.building .orbit { width: 120px; height: 120px; margin: 0 auto 18px; border-radius: 50%; border: 6px solid var(--primary-soft); border-top-color: var(--primary); animation: spin 1.1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.tips { margin-top: 18px; font-size: 14px; color: var(--muted); min-height: 42px; }

/* ---------- lesson / reading ---------- */
.lesson-head { margin: 4px 0 14px; }
.lesson-head .crumb { font-size: 13px; color: var(--muted); }
.lesson-head h2 { font-size: 26px; margin: 4px 0 8px; }
.prose { font-family: var(--read); font-size: 18px; line-height: 1.7; }
.prose h3 { font-family: var(--font); font-size: 18px; margin: 26px 0 8px; }
.prose p { margin: 0 0 14px; }
.prose ul, .prose ol { padding-left: 22px; margin: 0 0 14px; }
.prose li { margin: 6px 0; }
.prose blockquote { margin: 0 0 14px; padding: 10px 14px; border-left: 4px solid var(--primary); background: var(--surface-2); border-radius: 0 10px 10px 0; }
.prose strong { color: color-mix(in srgb, var(--primary) 45%, var(--text)); }
.prose mark { background: var(--accent-soft); color: inherit; padding: 0 2px; border-radius: 4px; }
.prose code { font-size: .9em; background: var(--surface-2); padding: 1px 5px; border-radius: 5px; }
.callout { border-radius: var(--radius); padding: 16px 18px; margin: 16px 0; }
.callout h4 { margin: 0 0 6px; font-size: 15px; display: flex; gap: 8px; align-items: center; }
.callout.analogy { background: var(--accent-soft); }
.callout.example { background: var(--good-soft); }
.callout.points { background: var(--primary-soft); }
.terms { display: grid; gap: 8px; }
.term { border: 1px solid var(--border); border-radius: 12px; background: var(--surface); }
.term summary { padding: 12px 14px; font-weight: 700; cursor: pointer; list-style: none; display: flex; justify-content: space-between; }
.term summary::-webkit-details-marker { display: none; }
.term summary::after { content: "Tap to reveal"; font-size: 12px; font-weight: 600; color: var(--muted); }
.term[open] summary::after { content: ""; }
.term p { margin: 0; padding: 0 14px 12px; color: var(--text); }
.explain-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { border: 1px solid var(--border); background: var(--surface); padding: 8px 12px; border-radius: 99px; font-weight: 600; font-size: 14px; cursor: pointer; }
.chip:hover, .chip.on { border-color: var(--primary); color: var(--primary); background: var(--primary-soft); }
.engine-note { font-size: 12px; color: var(--muted); display: flex; gap: 6px; align-items: center; }

/* ---------- bite player ---------- */
.player { display: flex; flex-direction: column; min-height: calc(100dvh - 140px); }
.player-top { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.player-top .bar { flex: 1; height: 12px; }
.bite { flex: 1; animation: rise .25s ease; }
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.bite-kicker { font-size: 13px; font-weight: 800; text-transform: uppercase; letter-spacing: .06em; color: var(--primary); }
.bite h3 { font-size: 24px; margin: 6px 0 12px; }
.bite .prose { font-size: 19px; }
.player-foot { position: sticky; bottom: calc(var(--nav-h) + env(safe-area-inset-bottom)); padding: 14px 0 10px; background: linear-gradient(transparent, var(--bg) 30%); }
@media (min-width: 900px) { .player-foot { bottom: 0; } }

/* ---------- questions ---------- */
.q-prompt { font-size: 21px; font-weight: 700; line-height: 1.4; margin: 6px 0 18px; white-space: pre-line; }
.q-prompt strong { color: var(--primary); }
.options { display: grid; gap: 10px; }
.option { display: flex; align-items: center; gap: 12px; width: 100%; min-height: 56px; padding: 12px 14px; text-align: left; border: 2px solid var(--border); border-radius: 14px; background: var(--surface); cursor: pointer; font-size: 16px; line-height: 1.35; transition: border-color .12s, background .12s, transform .08s; }
.option:hover:not([disabled]) { border-color: var(--primary); }
.option:active:not([disabled]) { transform: scale(0.99); }
.option .key { width: 30px; height: 30px; border-radius: 8px; display: grid; place-items: center; font-weight: 800; font-size: 14px; background: var(--surface-2); color: var(--muted); flex: none; }
.option.picked { border-color: var(--primary); background: var(--primary-soft); }
.option.right { border-color: var(--good); background: var(--good-soft); }
.option.right .key { background: var(--good); color: #fff; }
.option.wrong { border-color: var(--bad); background: var(--bad-soft); }
.option.wrong .key { background: var(--bad); color: #fff; }
.option[disabled] { cursor: default; }
.feedback { margin-top: 16px; padding: 16px; border-radius: 14px; animation: rise .2s ease; }
.feedback.good { background: var(--good-soft); }
.feedback.bad { background: var(--bad-soft); }
.feedback h4 { margin: 0 0 6px; font-size: 18px; }
.feedback .src { margin-top: 8px; font-size: 14px; color: var(--muted); font-style: italic; }
.qmeta { display: flex; justify-content: space-between; align-items: center; font-size: 14px; color: var(--muted); }
.timer { font-variant-numeric: tabular-nums; font-weight: 800; font-size: 18px; color: var(--text); }
.timer.low { color: var(--bad); }
.combo { font-weight: 800; color: #ea580c; }
.exam-nav { display: grid; grid-template-columns: repeat(auto-fill, minmax(38px, 1fr)); gap: 6px; }
.exam-nav button { height: 38px; border-radius: 9px; border: 1.5px solid var(--border); background: var(--surface); font-weight: 700; cursor: pointer; }
.exam-nav button.answered { background: var(--primary-soft); border-color: var(--primary); color: var(--primary); }
.exam-nav button.current { outline: 3px solid var(--accent); }
.result-hero { text-align: center; padding: 10px 0 6px; }
.result-hero h2 { font-size: 28px; margin: 14px 0 4px; }
.review-item { border-left: 4px solid var(--bad); }
.review-item.ok { border-left-color: var(--good); }

/* ---------- flashcards ---------- */
.flash-wrap { perspective: 1200px; }
.flash { position: relative; min-height: 300px; cursor: pointer; transform-style: preserve-3d; transition: transform .45s cubic-bezier(.2,.8,.2,1); }
.flash.flipped { transform: rotateY(180deg); }
.flash-face { position: absolute; inset: 0; display: flex; flex-direction: column; justify-content: center; padding: 26px; border-radius: 22px; background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow-lg); backface-visibility: hidden; text-align: center; font-size: 22px; font-weight: 600; line-height: 1.4; }
.flash-face.back { transform: rotateY(180deg); background: var(--primary-soft); font-weight: 500; font-size: 20px; }
.flash-face small { position: absolute; top: 14px; left: 0; right: 0; font-size: 12px; font-weight: 700; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.grades { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin-top: 18px; }
.grades button { min-height: 60px; border-radius: 14px; border: 0; font-weight: 800; cursor: pointer; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 2px; }
.grades button span { font-size: 11px; font-weight: 600; opacity: .8; }
.g-again { background: var(--bad-soft); color: var(--bad); }
.g-hard { background: var(--accent-soft); color: color-mix(in srgb, var(--accent) 70%, var(--text)); }
.g-good { background: var(--good-soft); color: var(--good); }
.g-easy { background: var(--primary-soft); color: var(--primary); }

/* ---------- tutor ---------- */
.chat { display: flex; flex-direction: column; gap: 12px; padding-bottom: 90px; }
.msg { max-width: 88%; padding: 12px 14px; border-radius: 18px; line-height: 1.5; }
.msg.user { align-self: flex-end; background: var(--primary); color: var(--primary-ink); border-bottom-right-radius: 6px; }
.msg.assistant { align-self: flex-start; background: var(--surface); border: 1px solid var(--border); border-bottom-left-radius: 6px; }
.msg.assistant .prose { font-family: var(--font); font-size: 16px; }
.msg .cites { margin-top: 8px; display: flex; flex-wrap: wrap; gap: 6px; }
.msg .cites a { font-size: 12px; padding: 3px 8px; border-radius: 99px; background: var(--surface-2); }
.composer { position: fixed; left: 0; right: 0; bottom: calc(var(--nav-h) + env(safe-area-inset-bottom)); padding: 10px 16px; background: var(--bg); border-top: 1px solid var(--border); z-index: 10; }
.composer form { max-width: 760px; margin: 0 auto; display: flex; gap: 8px; }
.composer .input { min-height: 48px; }
@media (min-width: 900px) { .composer { left: 232px; bottom: 0; } }
.typing span { display: inline-block; width: 8px; height: 8px; margin-right: 4px; border-radius: 50%; background: var(--muted); animation: blink 1.2s infinite; }
.typing span:nth-child(2) { animation-delay: .2s; } .typing span:nth-child(3) { animation-delay: .4s; }
@keyframes blink { 0%, 80%, 100% { opacity: .2; } 40% { opacity: 1; } }

/* ---------- progress ---------- */
.heat { display: grid; grid-template-rows: repeat(7, 1fr); grid-auto-flow: column; gap: 4px; overflow-x: auto; padding-bottom: 4px; }
.heat i { width: 14px; height: 14px; border-radius: 4px; background: var(--surface-2); }
.heat i.l1 { background: color-mix(in srgb, var(--good) 30%, var(--surface-2)); }
.heat i.l2 { background: color-mix(in srgb, var(--good) 55%, var(--surface-2)); }
.heat i.l3 { background: color-mix(in srgb, var(--good) 80%, var(--surface-2)); }
.heat i.l4 { background: var(--good); }
.legend { display: flex; gap: 12px; flex-wrap: wrap; font-size: 12px; color: var(--muted); }
.legend span::before { content: ""; display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 5px; background: var(--mc); vertical-align: -1px; }
.mbar { display: flex; height: 12px; border-radius: 99px; overflow: hidden; background: var(--surface-2); }
.mbar i { display: block; height: 100%; background: var(--mc); }

/* ---------- misc ---------- */
.empty { text-align: center; padding: 34px 18px; }
.empty svg { width: 64px; height: 64px; margin: 0 auto 10px; color: var(--primary); }
.empty h3 { margin: 6px 0; }
.notice { padding: 12px 14px; border-radius: 12px; background: var(--accent-soft); font-size: 14px; }
.notice.error { background: var(--bad-soft); color: var(--bad); }
.notice.info { background: var(--primary-soft); }
#toast { position: fixed; left: 50%; bottom: calc(var(--nav-h) + 20px + env(safe-area-inset-bottom)); transform: translateX(-50%) translateY(20px); opacity: 0; pointer-events: none; z-index: 100; padding: 12px 18px; border-radius: 14px; background: var(--text); color: var(--bg); font-weight: 600; box-shadow: var(--shadow-lg); transition: all .25s ease; max-width: calc(100vw - 32px); }
#toast.show { opacity: 1; transform: translateX(-50%); }
#toast.xp { background: var(--accent); color: #062a4a; }
.boot { min-height: 100dvh; display: grid; place-items: center; }
.boot-mark { width: 44px; height: 44px; border-radius: 50%; border: 4px solid var(--primary-soft); border-top-color: var(--primary); animation: spin 1s linear infinite; }
.skeleton { background: linear-gradient(90deg, var(--surface-2), var(--surface), var(--surface-2)); background-size: 200% 100%; animation: shimmer 1.2s infinite; border-radius: 12px; min-height: 70px; }
@keyframes shimmer { to { background-position: -200% 0; } }
.celebrate { text-align: center; padding: 30px 10px; }
.celebrate .big-emoji { font-size: 64px; line-height: 1; }
.celebrate h2 { font-size: 28px; margin: 10px 0 6px; }
canvas.confetti { position: fixed; inset: 0; pointer-events: none; z-index: 200; }
.modal-back { position: fixed; inset: 0; z-index: 90; background: rgba(5, 26, 46, .5); display: grid; place-items: end center; padding: 0; animation: fade .15s ease; }
@keyframes fade { from { opacity: 0; } }
.modal { width: 100%; max-width: 560px; max-height: 88dvh; overflow: auto; background: var(--surface); border-radius: 22px 22px 0 0; padding: 20px 18px calc(20px + env(safe-area-inset-bottom)); animation: rise .2s ease; }
@media (min-width: 700px) { .modal-back { place-items: center; } .modal { border-radius: 22px; } }
.modal h3 { margin-top: 0; }
.table { width: 100%; border-collapse: collapse; font-size: 14px; }
.table th, .table td { text-align: left; padding: 8px 6px; border-bottom: 1px solid var(--border); vertical-align: top; }
.code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 20px; letter-spacing: .08em; font-weight: 700; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation: none !important; transition: none !important; } }

.page-title, .hello h2, .auth h2 { letter-spacing: -0.02em; }
.card { border-radius: var(--radius); }

/* =====================================================================
   v2 — sleek, modern, interactive (Haidar navy/teal system)
   ===================================================================== */
:root { --nav-h: 66px; --grad: linear-gradient(120deg, #062a4a 0%, #0b4f86 55%, #08a6ad 130%); --ring-soft: 0 0 0 4px color-mix(in srgb, var(--primary) 18%, transparent); }
body { background: radial-gradient(900px 420px at 85% -80px, color-mix(in srgb, var(--teal) 14%, transparent), transparent), radial-gradient(800px 380px at -10% -60px, color-mix(in srgb, var(--primary) 12%, transparent), transparent), var(--bg); background-attachment: fixed; }
h1, h2, h3 { font-weight: 800; }

/* glass navigation */
.topbar { padding: 10px 16px; background: color-mix(in srgb, var(--bg) 70%, transparent); backdrop-filter: blur(18px) saturate(1.4); -webkit-backdrop-filter: blur(18px) saturate(1.4); }
.brand { font-size: 17px; }
.brand-mark { width: 34px; height: 34px; border-radius: 10px; box-shadow: 0 4px 14px rgba(6, 42, 74, .28); }
.tabbar { left: 12px; right: 12px; bottom: calc(10px + env(safe-area-inset-bottom)); height: var(--nav-h); padding: 6px; border: 1px solid color-mix(in srgb, var(--border) 80%, transparent); border-radius: 26px; background: color-mix(in srgb, var(--surface) 78%, transparent); backdrop-filter: blur(20px) saturate(1.5); -webkit-backdrop-filter: blur(20px) saturate(1.5); box-shadow: 0 18px 50px rgba(6, 42, 74, .22); }
.tabbar a { border-radius: 20px; transition: background .2s, color .2s, transform .2s; }
.tabbar a.active { color: #fff; background: var(--grad); box-shadow: 0 8px 20px rgba(8, 121, 185, .35); }
.tabbar a:active { transform: scale(.94); }
.shell { padding-bottom: calc(var(--nav-h) + 30px + env(safe-area-inset-bottom)); }
#toast { bottom: calc(var(--nav-h) + 30px + env(safe-area-inset-bottom)); }
.composer { bottom: calc(var(--nav-h) + 22px + env(safe-area-inset-bottom)); }
@media (min-width: 900px) {
  .shell { padding-left: 252px; padding-bottom: 0; }
  .tabbar { left: 12px; top: 12px; bottom: 12px; right: auto; width: 228px; height: auto; border-radius: 26px; padding: 84px 12px 12px; grid-auto-rows: 50px; }
  .tabbar .side-brand { top: 24px; left: 22px; }
  .tabbar a { border-radius: 16px; }
  .composer { left: 252px; bottom: 0; }
  #toast { bottom: 30px; }
}

/* surfaces */
.card { border-color: color-mix(in srgb, var(--border) 85%, transparent); box-shadow: var(--shadow); }
.card.flat { box-shadow: none; background: color-mix(in srgb, var(--surface) 70%, transparent); }
.btn { border-radius: 14px; box-shadow: 0 1px 0 rgba(255,255,255,.18) inset; transition: transform .12s, box-shadow .2s, filter .2s; }
.btn:not(.soft):not(.ghost):not(.good):not(.danger) { background: var(--grad); box-shadow: 0 12px 28px rgba(8, 121, 185, .28); }
.btn:hover { filter: brightness(1.07); transform: translateY(-1px); }
.btn:active { transform: scale(.98); }
.btn.big { min-height: 58px; font-size: 18px; border-radius: 18px; }
.chip { transition: all .15s; }
.chip.on { background: var(--primary-soft); border-color: var(--primary); color: var(--primary); }
.chip svg { width: 14px; height: 14px; margin-left: 4px; vertical-align: -2px; }
.input:focus { box-shadow: var(--ring-soft); }
.plan-item, .action, .topic-row, .pack { transition: transform .15s, border-color .15s, box-shadow .2s; }
.plan-item:hover, .action:hover, .topic-row:hover, .pack:hover { transform: translateY(-2px); box-shadow: 0 14px 34px rgba(6, 42, 74, .12); }
.plan-item .pi-icon { border-radius: 14px; }
.pi-learn { background: linear-gradient(135deg, var(--primary-soft), color-mix(in srgb, var(--teal) 22%, var(--primary-soft))); }
.action svg { padding: 7px; width: 38px; height: 38px; border-radius: 12px; background: var(--primary-soft); }

/* today */
.card.goal { --surface: #0c3d68; --surface-2: rgba(255,255,255,.2); background: var(--grad); color: #fff; border: 0; box-shadow: 0 22px 50px rgba(6, 42, 74, .32); position: relative; overflow: hidden; }
.card.goal::after { content: ""; position: absolute; right: -50px; top: -60px; width: 200px; height: 200px; border-radius: 50%; background: radial-gradient(circle, rgba(22, 201, 194, .45), transparent 70%); }
.card.goal .muted { color: rgba(255,255,255,.78); }
.card.goal .bar.accent > i { background: linear-gradient(90deg, #edab72, #ffd9b0); }
.coach { display: flex; gap: 12px; align-items: flex-start; margin: 0 0 14px; animation: rise .35s ease; }
.coach-av { width: 46px; height: 46px; border-radius: 14px; flex: none; box-shadow: 0 8px 20px rgba(6, 42, 74, .3); animation: float 4s ease-in-out infinite; }
@keyframes float { 50% { transform: translateY(-4px); } }
.coach-bubble { position: relative; flex: 1; padding: 12px 14px 14px; border-radius: 4px 20px 20px 20px; background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow); }
.coach-bubble b { font-size: 12px; text-transform: uppercase; letter-spacing: .07em; color: var(--primary); }
.coach-bubble p { margin: 4px 0 8px; font-size: 15.5px; }
.coach-bubble .btn { margin-top: 2px; }

/* lesson player */
.player-top { gap: 12px; }
.segs { flex: 1; display: flex; gap: 4px; }
.segs i { flex: 1; height: 8px; border-radius: 99px; background: var(--surface-2); overflow: hidden; position: relative; }
.segs i::after { content: ""; position: absolute; inset: 0; background: var(--grad); transform: scaleX(0); transform-origin: left; transition: transform .35s ease; border-radius: inherit; }
.segs i.on::after { transform: scaleX(1); }
.segs i.now::after { transform: scaleX(.35); }
.chip-xp.bump { animation: bump .45s ease; }
@keyframes bump { 30% { transform: scale(1.25); } }
.bite { animation: rise .35s cubic-bezier(.2, .8, .2, 1); }
.bite-kicker { display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px; border-radius: 99px; background: var(--primary-soft); letter-spacing: .05em; font-size: 12px; }
.bite-kicker svg { width: 14px; height: 14px; }
.bite h3 { font-size: 26px; }
.bite-hero { padding: 26px 22px; border-radius: 26px; background: var(--grad); color: #fff; box-shadow: 0 22px 50px rgba(6, 42, 74, .3); position: relative; overflow: hidden; }
.bite-hero::after { content: ""; position: absolute; right: -40px; bottom: -60px; width: 220px; height: 220px; border-radius: 50%; background: radial-gradient(circle, rgba(237, 171, 114, .35), transparent 70%); }
.bite-hero .bite-kicker { background: rgba(255,255,255,.16); color: #fff; }
.bite-hero h3 { font-size: 30px; }
.bite-hero .prose, .bite-hero .muted { color: rgba(255,255,255,.9); }
.bite-hero .prose strong { color: #fff; }
.bite-card { padding: 22px 20px; border-radius: 24px; border: 1px solid var(--border); background: var(--surface); box-shadow: var(--shadow); }
.bite-card h3 { margin-top: 10px; }
.bite-card.why { background: linear-gradient(135deg, color-mix(in srgb, var(--teal) 14%, var(--surface)), var(--surface)); }
.lead-text { font-size: 21px; line-height: 1.5; font-weight: 600; margin: 12px 0 0; }
.bite-card.real { background: linear-gradient(160deg, var(--accent-soft), var(--surface) 70%); }
.insight { display: flex; gap: 10px; align-items: flex-start; margin-top: 14px; padding: 12px 14px; border-radius: 14px; background: color-mix(in srgb, var(--accent) 22%, var(--surface)); font-weight: 600; }
.insight svg { width: 20px; height: 20px; flex: none; margin-top: 2px; color: var(--accent); }
.bite-card.apply { border: 2px solid color-mix(in srgb, var(--primary) 55%, var(--border)); box-shadow: 0 0 0 6px color-mix(in srgb, var(--primary) 10%, transparent), var(--shadow); }
.bite-card.beyond { border: 2px dashed color-mix(in srgb, var(--teal) 70%, var(--border)); background: color-mix(in srgb, var(--teal) 7%, var(--surface)); }
.badge-added { display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px; border-radius: 99px; background: color-mix(in srgb, var(--teal) 18%, var(--surface)); color: color-mix(in srgb, var(--teal) 70%, var(--text)); font-size: 12px; font-weight: 800; }
.badge-added svg { width: 14px; height: 14px; }
.bite-card.share { background: var(--grad); color: #fff; border: 0; }
.bite-card.share .muted { color: rgba(255,255,255,.82); }
.bite-card.share .bite-kicker { background: rgba(255,255,255,.16); color: #fff; }
.share-text { white-space: pre-line; padding: 14px; margin: 12px 0; border-radius: 16px; background: rgba(255,255,255,.13); font-size: 15px; line-height: 1.55; }
.bite-card.share .btn.soft { background: rgba(255,255,255,.18); color: #fff; }
.bite-card.share .btn:not(.soft) { background: #fff; color: #062a4a; box-shadow: none; }
.option { border-radius: 16px; transition: transform .12s, border-color .15s, background .15s; }
.option:hover:not([disabled]) { transform: translateX(3px); background: color-mix(in srgb, var(--primary) 5%, var(--surface)); }
.feedback { border-radius: 18px; }
.feedback.good { border: 1px solid color-mix(in srgb, var(--good) 40%, transparent); }
.feedback.bad { border: 1px solid color-mix(in srgb, var(--bad) 30%, transparent); }
.stars { display: flex; gap: 4px; margin-bottom: 8px; }
.stars svg { width: 28px; height: 28px; color: var(--border); }
.stars span.on svg { color: var(--accent); fill: var(--accent); animation: pop .4s ease backwards; }
.stars span:nth-child(2).on svg { animation-delay: .12s; } .stars span:nth-child(3).on svg { animation-delay: .24s; }
@keyframes pop { 0% { transform: scale(0); } 70% { transform: scale(1.3); } }
.pop { animation: pop .3s ease; }
.shake { animation: shake .4s ease; }
@keyframes shake { 20%, 60% { transform: translateX(-6px); } 40%, 80% { transform: translateX(6px); } }

/* order + match + traps */
.order-done { list-style: none; counter-reset: o; padding: 0; margin: 12px 0; display: grid; gap: 8px; }
.order-done li { counter-increment: o; display: flex; gap: 10px; align-items: center; padding: 12px 14px; border-radius: 14px; background: var(--good-soft); border: 1px solid color-mix(in srgb, var(--good) 40%, transparent); font-weight: 600; }
.order-done li::before { content: counter(o); display: grid; place-items: center; width: 26px; height: 26px; border-radius: 50%; background: var(--good); color: #fff; font-size: 13px; font-weight: 800; flex: none; }
.order-pool { display: grid; gap: 8px; }
.big-chip { text-align: left; border-radius: 14px; padding: 13px 14px; font-size: 15px; border-width: 2px; }
.match { display: grid; grid-template-columns: 1fr 1.4fr; gap: 10px; margin-top: 8px; }
.match-col { display: grid; gap: 8px; align-content: start; }
.match-item { padding: 13px 12px; border-radius: 14px; border: 2px solid var(--border); background: var(--surface); text-align: left; cursor: pointer; font-size: 14.5px; line-height: 1.35; transition: all .15s; }
.match-item.term { font-weight: 800; }
.match-item:hover { border-color: var(--primary); }
.match-item.sel { border-color: var(--primary); background: var(--primary-soft); transform: scale(1.02); }
.match-item.done { border-color: var(--good); background: var(--good-soft); opacity: .55; pointer-events: none; }
.traps { display: grid; gap: 8px; }
.trap { border-radius: 16px; border: 1px solid var(--border); background: var(--surface); overflow: hidden; }
.trap summary { display: flex; gap: 10px; align-items: flex-start; padding: 13px 14px; cursor: pointer; font-weight: 700; list-style: none; }
.trap summary::-webkit-details-marker { display: none; }
.trap summary svg { width: 20px; height: 20px; flex: none; margin-top: 1px; color: var(--bad); }
.trap p { display: flex; gap: 10px; margin: 0; padding: 12px 14px; background: var(--good-soft); }
.trap p svg { width: 20px; height: 20px; flex: none; color: var(--good); margin-top: 2px; }
.celebrate .trophy { width: 96px; height: 96px; margin: 0 auto 8px; display: grid; place-items: center; border-radius: 30px; background: var(--grad); color: #ffd9b0; box-shadow: 0 22px 44px rgba(6, 42, 74, .35); animation: pop .6s ease; }
.celebrate .trophy svg { width: 52px; height: 52px; fill: currentColor; }
.next-up { margin: 18px auto 0; max-width: 380px; padding: 14px 16px; border-radius: 18px; background: var(--primary-soft); text-align: left; }
.next-up p { margin: 4px 0 0; }

/* onboarding + profile */
.wide-auth .card.onboard { max-width: 540px; }
.onboard .dots { display: flex; gap: 6px; justify-content: center; margin-bottom: 14px; }
.onboard .dots i { width: 34px; height: 6px; border-radius: 99px; background: var(--surface-2); transition: background .2s; }
.onboard .dots i.on { background: var(--grad); }
.choice-grid { display: grid; gap: 8px; }
.choice { text-align: left; padding: 13px 14px; border-radius: 14px; border: 2px solid var(--border); background: var(--surface); font-weight: 700; cursor: pointer; }
.choice.on { border-color: var(--primary); background: var(--primary-soft); color: var(--primary); }
.tags .tag-list, .tags .tag-sugg { display: flex; flex-wrap: wrap; gap: 6px; margin: 6px 0; }
.tags .tag-sugg .chip { font-size: 13px; padding: 6px 10px; opacity: .85; }
.skipped summary { cursor: pointer; display: flex; align-items: center; gap: 10px; font-weight: 700; list-style: none; }
.skipped summary::-webkit-details-marker { display: none; }
.skipped summary svg { width: 20px; height: 20px; color: var(--muted); }
.skipped summary small { margin-left: auto; color: var(--muted); font-weight: 600; }
.skip-row { display: flex; align-items: center; gap: 12px; padding: 10px 0; border-top: 1px solid var(--border); }
.skip-row .fr-body { flex: 1; min-width: 0; }
.skip-row .fr-body b { display: block; font-size: 14px; }
.skip-row .fr-body span { font-size: 12px; color: var(--muted); text-transform: capitalize; }
.auth { background: radial-gradient(900px 500px at 50% -120px, color-mix(in srgb, var(--teal) 22%, transparent), transparent), radial-gradient(700px 400px at 100% 100%, color-mix(in srgb, var(--primary) 18%, transparent), transparent), var(--bg); }
.auth .card { border-radius: 28px; box-shadow: var(--shadow-lg); }
.auth .brand-mark { width: 60px; height: 60px; border-radius: 18px; }
.auth .brand { flex-direction: column; gap: 10px; text-align: center; }
.msg.user { background: var(--grad); }
.msg.assistant { border-radius: 20px 20px 20px 6px; }
.topic-num { border-width: 3px; }
.stat b { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

.player { padding-bottom: 96px; }
.player-foot { position: fixed; left: 0; right: 0; bottom: calc(var(--nav-h) + 22px + env(safe-area-inset-bottom)); padding: 12px 16px; background: linear-gradient(transparent, var(--bg) 40%); z-index: 15; }
.player-foot .btn { max-width: 728px; margin: 0 auto; display: flex; }
@media (min-width: 900px) { .player-foot { left: 252px; bottom: 0; } }