/* VU Ready — app layout and pages. Theme variables live in style.css. */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.55 var(--font); min-height: 100vh; display: flex; flex-direction: column; }
a { color: var(--accent2); }
h1, h2, h3 { line-height: 1.2; margin: 0 0 .5em; }
h1 { font-size: clamp(1.5rem, 3.2vw, 2.1rem); }
h2 { font-size: 1.2rem; }
small { color: var(--muted); }
.muted { color: var(--muted); }
.center { text-align: center; }
.good { color: var(--good); } .bad { color: var(--bad); }
.skip { position: absolute; left: -999px; } .skip:focus { left: 8px; top: 8px; z-index: 99; background: var(--panel); padding: 8px; }
kbd { font: .8em var(--mono); border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 4px; padding: 0 4px; background: var(--panel); }
:focus-visible { outline: 2px solid var(--accent2); outline-offset: 2px; }

/* ---- header / nav ---- */
.top { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; gap: 16px; padding: 10px 20px;
  background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); }
.logo { display: flex; align-items: center; gap: 8px; text-decoration: none; color: var(--ink); font-size: 1.2rem; letter-spacing: .3px; }
.logo b { color: var(--accent); }
.logo-mark { font-size: 1.4rem; }
.main-nav { display: flex; gap: 2px; flex: 1; overflow-x: auto; scrollbar-width: none; }
.main-nav a { color: var(--muted); text-decoration: none; padding: 6px 10px; border-radius: 8px; white-space: nowrap; font-size: .95rem; }
.main-nav a:hover { color: var(--ink); background: var(--panel); }
.main-nav a.on { color: var(--accent); background: var(--panel); }
.top-right { display: flex; gap: 8px; align-items: center; margin-left: auto; }
.icon-btn { background: none; border: 1px solid var(--line); color: var(--ink); border-radius: 8px; width: 34px; height: 34px; cursor: pointer; font-size: 1rem; }
.tabbar { display: none; }
main { width: 100%; max-width: 1080px; margin: 0 auto; padding: 24px 20px 40px; flex: 1; outline: none; }
main.wide { max-width: 1240px; }
.foot { border-top: 1px solid var(--line); padding: 18px 20px 26px; color: var(--muted); font-size: .85rem; text-align: center; }
.foot p { max-width: 820px; margin: 4px auto; }

@media (max-width: 860px) {
  .main-nav { display: none; }
  .tabbar { display: flex; position: fixed; bottom: 0; left: 0; right: 0; z-index: 30; background: var(--panel); border-top: 1px solid var(--line);
    padding-bottom: env(safe-area-inset-bottom); }
  .tabbar a { flex: 1; display: flex; flex-direction: column; align-items: center; font-size: .7rem; color: var(--muted); text-decoration: none; padding: 6px 0; }
  .tabbar a span { font-size: 1.25rem; line-height: 1.3; }
  .tabbar a.on { color: var(--accent); }
  body { padding-bottom: 64px; }
  main { padding: 16px 14px 32px; }
  .top { padding: 8px 14px; }
  body[data-page=exam] .tabbar, body[data-page=lesson] .tabbar { display: none; }
  body[data-page=exam], body[data-page=lesson] { padding-bottom: 0; }
}

/* ---- buttons & bits ---- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; border: 1px solid var(--line); background: var(--panel); color: var(--ink);
  border-radius: 10px; padding: 9px 16px; font: 600 .95rem var(--font); cursor: pointer; text-decoration: none; transition: transform .1s, background .2s; }
.btn:hover { background: var(--panel2); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .45; cursor: default; }
.btn.primary { background: var(--accent); color: #1a1205; border-color: var(--accent); }
.btn.primary:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; }
.btn.small { padding: 5px 10px; font-size: .82rem; border-radius: 8px; }
.btn.big { padding: 13px 22px; font-size: 1.05rem; border-radius: 12px; }
.btn.good { background: var(--good); color: #062b14; border-color: var(--good); }
.btn.bad { background: transparent; color: var(--bad); border-color: var(--bad); }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); margin: 0 0 18px; }
.tag { display: inline-block; font-size: .75rem; padding: 2px 8px; border-radius: 999px; background: var(--panel2); color: var(--muted); border: 1px solid var(--line); }
.tag.g { color: var(--accent3); border-color: color-mix(in srgb, var(--accent3) 50%, transparent); }
.pill { font-size: .75rem; font-weight: 700; padding: 2px 8px; border-radius: 999px; }
.pill.ok { background: color-mix(in srgb, var(--good) 20%, transparent); color: var(--good); }
.pill.no { background: color-mix(in srgb, var(--bad) 20%, transparent); color: var(--bad); }
.bar { position: relative; height: 10px; background: var(--grid); border-radius: 99px; overflow: visible; flex: 1; min-width: 60px; }
.bar > span { display: block; height: 100%; border-radius: 99px; background: linear-gradient(90deg, var(--accent2), var(--accent)); transition: width .6s; }
.bar.thin { height: 6px; margin-top: 6px; }
.bar > i { position: absolute; top: -3px; bottom: -3px; width: 2px; background: var(--ink); opacity: .5; }
.mini-bar { display: block; height: 4px; background: var(--grid); border-radius: 4px; margin-top: 8px; overflow: hidden; }
.mini-bar span { display: block; height: 100%; background: var(--good); }
.page-head { margin-bottom: 18px; }
.page-head p { color: var(--muted); max-width: 760px; }
.back-link { display: inline-block; margin-bottom: 6px; text-decoration: none; }
.sec-h { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin: 28px 0 12px; }
.sec-badge { display: inline-grid; place-items: center; width: 30px; height: 30px; border-radius: 8px; font-weight: 800; font-size: .9rem; color: #111; }
.sec-badge.a { background: var(--accent); } .sec-badge.b { background: var(--accent2); } .sec-badge.m { background: var(--accent3); font-size: .7rem; }
table.t { border-collapse: collapse; width: 100%; font-size: .92rem; margin: 10px 0; }
table.t th, table.t td { border: 1px solid var(--line); padding: 7px 10px; text-align: left; vertical-align: top; }
table.t th { background: var(--panel2); }
.toast { position: fixed; left: 50%; bottom: 84px; transform: translate(-50%, 20px); background: var(--ink); color: var(--bg); padding: 10px 18px;
  border-radius: 10px; opacity: 0; transition: .25s; z-index: 99; font-weight: 600; max-width: 90vw; }
.toast.show { opacity: 1; transform: translate(-50%, 0); }

/* ---- home ---- */
.hero { display: grid; grid-template-columns: 1.3fr 1fr; gap: 24px; align-items: center; padding: 18px 0 8px; }
.eyebrow { text-transform: uppercase; letter-spacing: 2px; font-size: .78rem; color: var(--accent2); font-weight: 700; margin: 0 0 8px; }
.hero h1 { font-size: clamp(1.9rem, 4.6vw, 3rem); }
.glow { color: var(--accent); text-shadow: 0 0 24px color-mix(in srgb, var(--accent) 45%, transparent); }
.lead { font-size: 1.1rem; color: var(--muted); max-width: 560px; }
.cta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 18px; }
.hero-svg { width: 100%; max-width: 360px; display: block; margin: auto; }
.hero-svg .wave { fill: none; stroke: var(--accent); stroke-width: 2.5; opacity: 0; transform-origin: 160px 70px; animation: ripple 3.2s infinite ease-out; }
.hero-svg .w1 { animation-delay: .8s; } .hero-svg .w2 { animation-delay: 1.6s; } .hero-svg .w3 { animation-delay: 2.4s; }
@keyframes ripple { 0% { transform: scale(.4); opacity: .9; } 100% { transform: scale(6); opacity: 0; } }
.hero-svg .lamp { fill: var(--bad); animation: lamp 1.2s infinite steps(2); }
@keyframes lamp { 50% { fill: color-mix(in srgb, var(--bad) 30%, transparent); } }
.hero-svg .m { fill: var(--accent2); opacity: .25; animation: key 4s infinite; }
.hero-svg .m1 { animation-delay: .3s } .hero-svg .m2 { animation-delay: .6s } .hero-svg .m3 { animation-delay: .9s } .hero-svg .m4 { animation-delay: 1.2s }
.hero-svg .m5 { animation-delay: 1.5s } .hero-svg .m6 { animation-delay: 1.8s } .hero-svg .m7 { animation-delay: 2.1s }
@keyframes key { 0%, 100% { opacity: .2 } 8% { opacity: 1 } 20% { opacity: .2 } }
@media (prefers-reduced-motion: reduce) { .hero-svg * { animation: none !important; } .hero-svg .wave { opacity: .3; } }
.grade-pick { display: flex; gap: 20px; align-items: center; justify-content: space-between; flex-wrap: wrap; margin-top: 18px; }
.grade-pick h2 { margin: 0 0 4px; }
.grade-pick p { margin: 0; }
.seg { display: flex; gap: 10px; flex-wrap: wrap; }
.seg button { text-align: left; background: var(--panel2); border: 2px solid var(--line); color: var(--ink); border-radius: 12px; padding: 10px 16px; cursor: pointer; font: inherit; }
.seg button small { display: block; }
.seg button.on { border-color: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 25%, transparent); }
.home-grid { display: grid; grid-template-columns: 1.4fr 1fr; gap: 18px; }
.home-grid .card { margin: 0; }
.facts { padding-left: 18px; margin: 0 0 10px; }
.facts li { margin: 4px 0; }
.ready-card { text-decoration: none; color: var(--ink); display: block; }
.mini-rings { display: flex; gap: 10px; justify-content: space-around; margin: 10px 0; text-align: center; }
.mini-rings b { display: block; font-size: 1.6rem; color: var(--accent); }
.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 18px; }
.feature { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; text-decoration: none; color: var(--ink); transition: transform .15s, border-color .15s; }
.feature:hover { transform: translateY(-2px); border-color: var(--accent); }
.feature span { font-size: 1.6rem; display: block; }
.feature b { display: block; margin: 6px 0 2px; }
@media (max-width: 860px) {
  .hero { grid-template-columns: 1fr; } .hero-art { order: -1; } .hero-svg { max-width: 220px; }
  .home-grid { grid-template-columns: 1fr; } .features { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) { .features { grid-template-columns: 1fr; } }

/* ---- MCQ ---- */
.q-stem { font-size: 1.12rem; font-weight: 600; margin: 8px 0 14px; }
.opts { display: grid; gap: 10px; }
.opt { display: flex; gap: 12px; align-items: flex-start; text-align: left; background: var(--panel2); border: 2px solid var(--line); color: var(--ink);
  border-radius: 12px; padding: 12px 14px; font: inherit; cursor: pointer; transition: border-color .15s, background .15s; }
.opt b { flex: none; display: grid; place-items: center; width: 26px; height: 26px; border-radius: 50%; background: var(--panel); border: 1px solid var(--line); font-size: .85rem; }
.opt:hover:not(:disabled) { border-color: var(--accent2); }
.opt.chosen { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, var(--panel2)); }
.opt.right { border-color: var(--good); background: color-mix(in srgb, var(--good) 15%, var(--panel2)); }
.opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 15%, var(--panel2)); animation: shake .3s; }
.opt:disabled { cursor: default; }
@keyframes shake { 25% { transform: translateX(-4px); } 75% { transform: translateX(4px); } }
.explain { margin-top: 14px; padding: 12px 14px; border-radius: 10px; border-left: 4px solid; background: var(--panel2); }
.explain.ok { border-color: var(--good); } .explain.no { border-color: var(--bad); }

/* ---- learn ---- */
.lesson-grid, .topic-grid, .lab-grid, .deck-grid, .paper-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 12px; }
.lesson-card, .topic-card, .lab-card, .deck { display: flex; gap: 14px; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 14px 16px; text-decoration: none; color: var(--ink); transition: border-color .15s, transform .15s; }
.lesson-card:hover, .topic-card:hover, .lab-card:hover, .deck:hover { border-color: var(--accent); transform: translateY(-2px); }
.lesson-card.done { border-color: color-mix(in srgb, var(--good) 50%, var(--line)); }
.lc-icon, .tc-icon { font-size: 1.7rem; line-height: 1; }
.lc-body, .tc-body { display: flex; flex-direction: column; flex: 1; min-width: 0; }
.lc-num { font: 700 .75rem var(--mono); color: var(--accent); }
.lc-meta { font-size: .78rem; color: var(--muted); margin-top: 4px; }
.lesson { max-width: 820px; margin: 0 auto; }
.lesson-top, .drill-top { display: flex; gap: 12px; align-items: center; margin-bottom: 10px; }
.lesson-top h1 { font-size: 1.35rem; margin: 0; }
.back { text-decoration: none; font-size: 1.3rem; width: 38px; height: 38px; display: grid; place-items: center; border-radius: 10px; background: var(--panel); border: 1px solid var(--line); color: var(--ink); flex: none; }
.dots { display: flex; gap: 5px; margin: 6px 0 14px; flex-wrap: wrap; }
.dots button { width: 22px; height: 6px; border-radius: 4px; border: 0; background: var(--grid); cursor: pointer; padding: 0; }
.dots button.seen { background: color-mix(in srgb, var(--accent) 55%, var(--grid)); }
.dots button.cur { background: var(--accent); width: 34px; }
.step { min-height: 300px; outline: none; animation: fadein .25s; }
@keyframes fadein { from { opacity: 0; transform: translateY(6px); } }
.step-nav { position: sticky; bottom: 0; display: flex; justify-content: space-between; align-items: center; gap: 10px; padding: 12px 0;
  background: linear-gradient(transparent, var(--bg) 30%); }
.step-nav #count { color: var(--muted); font-size: .9rem; }
.prose p { margin: 0 0 .8em; }
.prose ul, .prose ol { padding-left: 1.3em; }
.prose li { margin: .25em 0; }
.prose svg { max-width: 100%; height: auto; }
.formula { display: inline-block; font: 600 1.05rem var(--mono); color: var(--accent); background: var(--panel2); border: 1px solid var(--line); padding: 2px 10px; border-radius: 8px; }
.tip, .warn, .g-only { border-radius: 10px; padding: 10px 14px 10px 44px; margin: 12px 0; position: relative; background: var(--panel2); }
.tip::before, .warn::before, .g-only::before { position: absolute; left: 14px; top: 9px; }
.tip { border-left: 4px solid var(--accent2); } .tip::before { content: '💡'; }
.warn { border-left: 4px solid var(--bad); } .warn::before { content: '⚠️'; }
.g-only { border-left: 4px solid var(--accent3); } .g-only::before { content: 'G'; font-weight: 800; color: var(--accent3); }
.keypoints { padding-left: 0; list-style: none; }
.keypoints li { padding: 8px 10px 8px 34px; position: relative; border-bottom: 1px dashed var(--line); }
.keypoints li::before { content: '✓'; position: absolute; left: 8px; color: var(--good); font-weight: 800; }
.finish { text-align: center; padding: 30px 10px; position: relative; overflow: hidden; }
.finish-actions { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; margin-top: 16px; }
.confetti i { position: absolute; top: -10px; width: 8px; height: 14px; background: var(--accent); animation: fall 2.4s ease-in forwards; opacity: .9; }
.confetti i:nth-child(3n) { background: var(--accent2); } .confetti i:nth-child(3n+1) { background: var(--accent3); }
@keyframes fall { to { transform: translateY(420px) rotate(540deg); opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .confetti { display: none; } .step { animation: none; } }

/* ---- practice ---- */
.quick-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.big-btn { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; text-decoration: none; color: var(--ink); display: flex; flex-direction: column; gap: 2px; }
.big-btn span { font-size: 1.6rem; }
.big-btn:hover { border-color: var(--accent); }
.big-btn.disabled { opacity: .55; pointer-events: none; }
@media (max-width: 760px) { .quick-row { grid-template-columns: 1fr 1fr; } }
.drill, .flash { max-width: 760px; margin: 0 auto; }
.drill-top > div { flex: 1; }
.progress-line { height: 6px; background: var(--grid); border-radius: 6px; overflow: hidden; margin-top: 4px; }
.progress-line span { display: block; height: 100%; background: var(--accent); transition: width .3s; }
.count { font: 600 .9rem var(--mono); color: var(--muted); }
.q-meta { display: flex; gap: 6px; align-items: center; flex-wrap: wrap; justify-content: space-between; }
.drill-actions { margin-top: 14px; text-align: right; }
.hint-keys { font-size: .8rem; color: var(--muted); text-align: center; }
@media (hover: none) { .hint-keys { display: none; } }
.result-card { text-align: center; }
.result-card.pass { border-color: color-mix(in srgb, var(--good) 50%, var(--line)); }
.result-card.fail { border-color: color-mix(in srgb, var(--bad) 40%, var(--line)); }
.big-score { font: 800 3.2rem var(--mono); color: var(--accent); }
.big-score small { font-size: 1.4rem; }
.verdict { font-size: 2rem; font-weight: 800; }
.result-card.pass .verdict { color: var(--good); } .result-card.fail .verdict { color: var(--bad); }
.review { padding-left: 1.4em; }
.review li { background: var(--panel); border: 1px solid var(--line); border-left: 4px solid var(--good); border-radius: 10px; padding: 10px 14px; margin: 0 0 10px; }
.review li.no { border-left-color: var(--bad); }
.review p { margin: 2px 0; }

/* ---- exam ---- */
.exam-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.exam-card { text-align: left; background: var(--panel); border: 2px solid var(--line); border-radius: var(--radius); padding: 18px; color: var(--ink); font: inherit; cursor: pointer; display: flex; flex-direction: column; gap: 4px; }
.exam-card:hover { border-color: var(--accent); }
.exam-card.rec { border-color: var(--accent); }
.exam-card.rec::after { content: 'Your grade'; align-self: flex-start; font-size: .7rem; background: var(--accent); color: #1a1205; padding: 1px 8px; border-radius: 99px; margin-top: 6px; font-weight: 700; }
.ec-icon { font-size: 1.5rem; }
@media (max-width: 760px) { .exam-grid { grid-template-columns: 1fr; } }
.paper-card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px; display: flex; flex-direction: column; gap: 4px; }
.pc-actions { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 8px; }
.resume { border-color: var(--accent); }
.hist td, .hist th { white-space: nowrap; }
.exam { max-width: 1100px; margin: 0 auto; }
.exam-bar { position: sticky; top: 56px; z-index: 10; display: flex; align-items: center; gap: 12px; justify-content: space-between; background: var(--panel);
  border: 1px solid var(--line); border-radius: 12px; padding: 10px 14px; margin-bottom: 14px; }
.timer { font: 700 1.25rem var(--mono); color: var(--accent2); }
.timer.low { color: var(--bad); animation: lamp 1s infinite; }
.exam-body { display: grid; grid-template-columns: 1fr 300px; gap: 16px; align-items: start; }
.qgrid-wrap { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px; position: sticky; top: 128px; }
.qgrid-head { display: flex; justify-content: space-between; font-size: .8rem; color: var(--muted); margin-bottom: 8px; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin: 0 3px 0 8px; vertical-align: -1px; }
.legend i.a { background: var(--accent2); } .legend i.f { background: var(--accent3); }
.qgrid { display: grid; grid-template-columns: repeat(10, 1fr); gap: 4px; max-height: 60vh; overflow: auto; }
.qg-sec { grid-column: 1 / -1; font-size: .72rem; color: var(--muted); margin-top: 6px; }
.qgrid button { aspect-ratio: 1; border: 1px solid var(--line); background: var(--panel2); color: var(--ink); border-radius: 6px; font: .72rem var(--mono); cursor: pointer; padding: 0; }
.qgrid button.a { background: color-mix(in srgb, var(--accent2) 40%, var(--panel2)); }
.qgrid button.f { box-shadow: inset 0 -3px 0 var(--accent3); }
.qgrid button.cur { outline: 2px solid var(--accent); }
.qnav { display: flex; justify-content: space-between; gap: 8px; margin-top: 16px; align-items: center; }
.flag { background: none; border: 1px solid var(--line); color: var(--muted); border-radius: 8px; padding: 3px 10px; cursor: pointer; font: inherit; font-size: .8rem; }
.flag.on { color: var(--accent3); border-color: var(--accent3); }
@media (max-width: 860px) {
  .exam-body { grid-template-columns: 1fr; }
  .qgrid-wrap { position: static; order: 2; }
  .exam-bar { top: 50px; }
}
.rings { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin: 10px 0; }
.ring-num { font: 800 22px var(--mono); fill: var(--ink); }
.ring-lbl { font: 11px var(--font); fill: var(--muted); }
.topic-bars { display: grid; gap: 8px; }
.tb { display: grid; grid-template-columns: minmax(150px, 230px) 1fr 52px auto auto; gap: 10px; align-items: center; font-size: .9rem; }
@media (max-width: 640px) { .tb { grid-template-columns: 1fr 48px auto; } .tb .bar { grid-column: 1 / -1; order: 5; } .tb small { display: none; } }
.filters { margin-left: auto; display: flex; gap: 6px; }

/* ---- print paper ---- */
.print-paper { max-width: 820px; margin: 0 auto; }
.print-bar { display: flex; gap: 10px; margin-bottom: 14px; }
.pq > li { margin: 0 0 10px; break-inside: avoid; }
.pq p { margin: 0; font-weight: 600; }
.pq ol { margin: 2px 0; display: grid; grid-template-columns: 1fr 1fr; column-gap: 20px; }
.key { display: grid; grid-template-columns: repeat(10, 1fr); gap: 4px; font: .9rem var(--mono); }
@media print {
  .top, .tabbar, .foot, .no-print { display: none !important; }
  body { background: #fff; color: #000; padding: 0; }
  main { padding: 0; max-width: none; }
  .print-paper h1 { font-size: 18pt; } .print-paper { font-size: 10.5pt; }
  .page-break { break-before: page; }
  a { color: #000; }
}

/* ---- flashcards ---- */
.deck { flex-direction: column; gap: 2px; }
.deck-icon { font-size: 1.6rem; }
.due { color: var(--accent); font-weight: 700; }
.rev-toggle { display: block; text-align: right; font-size: .85rem; color: var(--muted); margin: 6px 0; }
.fcard { position: relative; display: block; width: 100%; height: 240px; perspective: 900px; background: none; border: 0; cursor: pointer; padding: 0; font: inherit; color: var(--ink); }
.fcard .face { position: absolute; inset: 0; display: grid; place-items: center; padding: 20px; text-align: center; border-radius: 18px; border: 1px solid var(--line);
  backface-visibility: hidden; transition: transform .5s; background: var(--panel); box-shadow: var(--shadow); font-size: 1.35rem; }
.fcard .front { font: 800 2.4rem var(--mono); color: var(--accent); }
.fcard .back { transform: rotateY(180deg); background: var(--panel2); }
.fcard.flipped .front { transform: rotateY(-180deg); }
.fcard.flipped .back { transform: rotateY(0); }
.fc-actions { display: flex; gap: 12px; justify-content: center; margin-top: 16px; }
.fc-actions .btn { flex: 1; max-width: 220px; padding: 14px; }

/* ---- progress ---- */
.stat-row { display: grid; grid-template-columns: repeat(5, 1fr); gap: 10px; margin-bottom: 18px; }
.stat { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 12px; text-align: center; }
.stat b { display: block; font: 800 1.5rem var(--mono); color: var(--accent); }
@media (max-width: 760px) { .stat-row { grid-template-columns: repeat(3, 1fr); } }
.hist-chart { width: 100%; height: auto; }
.hist-chart path { fill: none; stroke-width: 2.5; }
.hist-chart .l-a { stroke: var(--accent); } .hist-chart .l-b { stroke: var(--accent2); } .hist-chart .l-t { stroke: var(--ink); stroke-dasharray: 4 4; }
.hist-chart .passline { stroke: var(--bad); stroke-dasharray: 3 5; }
.hist-chart .axis { fill: var(--muted); font-size: 11px; }
.hist-chart .dot-ok { fill: var(--good); } .hist-chart .dot-no { fill: var(--bad); }
.legend-row { display: flex; gap: 16px; font-size: .8rem; color: var(--muted); }
.legend-row span::before { content: ''; display: inline-block; width: 14px; height: 3px; margin-right: 6px; vertical-align: middle; }
.k-a::before { background: var(--accent); } .k-b::before { background: var(--accent2); } .k-t::before { background: var(--ink); }
.lesson-check { columns: 2; padding-left: 0; list-style: none; }
.lesson-check li { padding: 3px 0; }
.lesson-check li::before { content: '○ '; color: var(--muted); }
.lesson-check li.done::before { content: '● '; color: var(--good); }
@media (max-width: 600px) { .lesson-check { columns: 1; } }

/* ---- lab, auth, settings, guide ---- */
.lab-card { flex-direction: column; gap: 2px; }
.auth { max-width: 440px; margin: 20px auto; }
.auth form { display: grid; gap: 12px; }
.auth label, .settings label { display: grid; gap: 4px; font-size: .9rem; color: var(--muted); }
.auth input, .settings select { background: var(--panel2); color: var(--ink); border: 1px solid var(--line); border-radius: 10px; padding: 11px 12px; font: inherit; }
.form-msg { min-height: 1.2em; margin: 0; }
.form-msg.bad { color: var(--bad); } .form-msg.good { color: var(--good); }
.auth-links { font-size: .9rem; text-align: center; }
.settings { max-width: 520px; display: grid; gap: 14px; }
.guide h2 { margin-top: 1.2em; color: var(--accent); }
.lab-one { max-width: 900px; }
.lab-one .w-svg { max-height: 72vh; }
.mt-host { margin-top: 4px; }