:root {
  --bg: #0e1016;
  --bg-soft: #151823;
  --card: #1a1e2c;
  --card-2: #212636;
  --border: #2a3042;
  --text: #e7e9f2;
  --muted: #9aa3b8;
  --accent: #6d8bff;
  --green: #2fbf71;
  --red: #ef4b5d;
  --amber: #f0a92b;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: radial-gradient(1200px 600px at 80% -10%, #1b2140 0%, var(--bg) 55%);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  line-height: 1.5;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
button { font-family: inherit; cursor: pointer; }
.hidden { display: none !important; }

/* Layout */
.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 1rem;
  padding: .8rem 1.4rem;
  background: rgba(14,16,22,.85); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.brand { font-weight: 800; font-size: 1.05rem; letter-spacing: .3px; }
.brand .dot { color: var(--red); }
.topbar .spacer { flex: 1; }
.topbar a.navlink { color: var(--muted); font-weight: 600; font-size: .9rem; padding: .3rem .6rem; border-radius: 8px; }
.topbar a.navlink:hover { color: var(--text); background: var(--card); }
.streak-pill { background: var(--card); border: 1px solid var(--border); border-radius: 20px; padding: .25rem .8rem; font-size: .82rem; color: var(--muted); }

.container { max-width: 1080px; margin: 0 auto; padding: 1.6rem 1.4rem 5rem; }

h1.page-title { font-size: 1.9rem; font-weight: 800; margin: .2rem 0 .3rem; }
.subtitle { color: var(--muted); margin: 0 0 1.6rem; }

/* Mode cards (home) */
.mode-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin-bottom: 2.2rem; }
.mode-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.4rem; text-align: left; transition: transform .15s, box-shadow .15s, border-color .15s;
  display: flex; flex-direction: column; gap: .4rem; color: inherit;
}
.mode-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--accent); }
.mode-card .ic { font-size: 2rem; }
.mode-card .t { font-weight: 800; font-size: 1.15rem; }
.mode-card .d { color: var(--muted); font-size: .9rem; }
.mode-card.exam { background: linear-gradient(135deg, #3a1220, #4a1230); border-color: #7a2440; }
.mode-card.exam .t { color: #ffb3c0; }

/* File grid */
.section-h { font-size: 1.05rem; font-weight: 800; margin: 1.4rem 0 .4rem; }
.section-sub { color: var(--muted); font-size: .88rem; margin: 0 0 1rem; }
.file-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: .9rem; }
.file-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1rem; position: relative; overflow: hidden;
  border-left: 5px solid var(--fc, var(--accent));
  transition: transform .15s, box-shadow .15s;
}
.file-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.file-card .fhead { display: flex; align-items: center; gap: .6rem; margin-bottom: .5rem; }
.file-badge { width: 34px; height: 34px; border-radius: 9px; display: grid; place-items: center; font-weight: 800; color: #fff; background: var(--fc, var(--accent)); }
.file-card .fname { font-weight: 700; font-size: .92rem; }
.file-card .flessons { color: var(--muted); font-size: .8rem; margin: .1rem 0 .8rem; padding-left: 1rem; }
.file-card .flessons li { margin-bottom: .1rem; }
.file-actions { display: flex; gap: .4rem; flex-wrap: wrap; }
.chip-progress { position: absolute; top: .8rem; right: .8rem; font-size: .72rem; color: var(--muted); }

/* Buttons */
.btn { border: 1px solid var(--border); background: var(--card-2); color: var(--text);
  padding: .5rem .9rem; border-radius: 9px; font-weight: 600; font-size: .88rem; transition: background .12s, border-color .12s, transform .08s; }
.btn:hover { background: #2b3246; }
.btn:active { transform: scale(.98); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #0b1020; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.red { background: var(--red); border-color: var(--red); color: #fff; }
.btn.green { background: var(--green); border-color: var(--green); color: #04210f; }
.btn.ghost { background: transparent; }
.btn.sm { padding: .35rem .7rem; font-size: .82rem; }
.btn.lg { padding: .8rem 1.4rem; font-size: 1rem; }
.btn.block { width: 100%; text-align: center; }
.btn:disabled { opacity: .5; cursor: default; }

/* Repaso */
.repaso-hero { border-radius: var(--radius); padding: 1.4rem 1.6rem; margin-bottom: 1.4rem; color: #fff;
  background: linear-gradient(135deg, var(--fc), #000a); }
.repaso-hero .ey { opacity: .8; font-size: .82rem; font-weight: 600; }
.repaso-hero h1 { margin: .1rem 0; font-size: 1.8rem; }
.repaso-cols { display: grid; grid-template-columns: 1.4fr 1fr; gap: 1.4rem; align-items: start; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.1rem 1.2rem; margin-bottom: 1.1rem; }
.lesson { border-left: 4px solid var(--fc, var(--accent)); padding-left: .9rem; margin-bottom: 1.3rem; }
.lesson .lh { display: flex; align-items: center; gap: .5rem; margin-bottom: .3rem; }
.lesson .lcode { background: var(--fc, var(--accent)); color: #fff; font-weight: 800; font-size: .78rem; padding: 1px 8px; border-radius: 6px; }
.lesson .ltitle { font-weight: 700; }
.lesson .lnote { color: var(--muted); font-size: .84rem; margin-bottom: .5rem; }
.rule { background: var(--card-2); border-radius: 8px; padding: .5rem .7rem; margin-bottom: .35rem; font-size: .9rem; }
.rule em, .rule code { color: #a9b6ff; font-style: normal; }
.trap { background: #35281a; border: 1px solid #7a5320; border-radius: 8px; padding: .5rem .7rem; margin-bottom: .35rem; font-size: .87rem; }
.book-fig { margin: .6rem 0 1rem; }
.book-fig img { width: 100%; border-radius: 10px; border: 1px solid var(--border); display: block; cursor: zoom-in; background:#fff; }
.book-fig .cap { color: var(--muted); font-size: .78rem; margin-top: .3rem; }
.phrase { display: inline-block; background: var(--card-2); border: 1px solid var(--border); border-radius: 18px; padding: .25rem .75rem; font-size: .85rem; margin: 0 .3rem .3rem 0; }
.vocab-scroll { max-height: 72vh; overflow-y: auto; }
.topic-h { color: var(--fc, var(--accent)); font-weight: 700; text-transform: uppercase; font-size: .74rem; letter-spacing: .04em; margin: .9rem 0 .3rem; }
.vrow { display: flex; justify-content: space-between; gap: 1rem; padding: .3rem 0; border-bottom: 1px solid var(--border); font-size: .9rem; }
.vrow:last-child { border: none; }
.vrow .ven { font-weight: 600; }
.vrow .vpos { color: #5a6480; font-size: .68rem; text-transform: uppercase; margin-left: .35rem; }
.vrow .ves { color: var(--muted); text-align: right; }

/* Repaso tabs */
.tabbar { display: flex; gap: .4rem; flex-wrap: wrap; margin-bottom: 1.3rem; position: sticky; top: 52px; z-index: 10;
  background: var(--bg); padding: .5rem 0; }
.tab { border: 1px solid var(--border); background: var(--card); color: var(--muted); padding: .45rem .9rem;
  border-radius: 10px; font-weight: 700; font-size: .88rem; transition: color .12s, background .12s, border-color .12s; }
.tab:hover { color: var(--text); border-color: var(--fc, var(--accent)); }
.tab.active { background: var(--fc, var(--accent)); border-color: var(--fc, var(--accent)); color: #fff; }
.tabpanel { animation: fadeIn .18s ease; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: none; } }
.reading { max-width: 760px; }
.vocab-cols { column-count: 2; column-gap: 2rem; }
.vocab-group { break-inside: avoid; margin-bottom: .4rem; }
@media (max-width: 720px) { .vocab-cols { column-count: 1; } .tabbar { top: 48px; } }

/* Quiz */
.quiz-top { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; }
.progress-track { flex: 1; height: 8px; background: var(--card-2); border-radius: 5px; overflow: hidden; }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent), #9db4ff); width: 0; transition: width .3s; }
.quiz-meta { color: var(--muted); font-size: .85rem; white-space: nowrap; }
.qcard { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.6rem; box-shadow: var(--shadow); }
.qtag { display: inline-block; font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .04em;
  color: var(--muted); background: var(--card-2); border: 1px solid var(--border); padding: 2px 8px; border-radius: 6px; margin-bottom: .8rem; }
.qprompt { font-size: 1.25rem; font-weight: 600; margin-bottom: 1.2rem; }
.qprompt em, .qprompt strong { color: #a9b6ff; }
.qprompt .blank { color: var(--amber); font-weight: 800; letter-spacing: 2px; }
.opts { display: grid; gap: .6rem; }
.opt { text-align: left; padding: .8rem 1rem; border-radius: 10px; border: 1px solid var(--border); background: var(--card-2); color: var(--text); font-size: 1rem; transition: border-color .1s, background .1s; }
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt.correct { background: rgba(47,191,113,.16); border-color: var(--green); }
.opt.wrong { background: rgba(239,75,93,.16); border-color: var(--red); }
.qinput { display: flex; gap: .6rem; }
.qinput input { flex: 1; padding: .8rem 1rem; font-size: 1.05rem; border-radius: 10px; border: 1px solid var(--border); background: var(--card-2); color: var(--text); }
.qinput input:focus { outline: none; border-color: var(--accent); }
.qhint { color: var(--muted); font-size: .82rem; margin-top: .5rem; }
.feedback { margin-top: 1.1rem; padding: .9rem 1rem; border-radius: 10px; font-size: .92rem; }
.feedback.ok { background: rgba(47,191,113,.14); border: 1px solid var(--green); }
.feedback.no { background: rgba(239,75,93,.14); border: 1px solid var(--red); }
.feedback .fa { font-weight: 800; }
.feedback .exp { color: var(--muted); margin-top: .3rem; }
.quiz-foot { display: flex; justify-content: flex-end; margin-top: 1.2rem; }

/* Results */
.result-hero { text-align: center; padding: 2rem 1rem 1rem; }
.grade-ring { width: 150px; height: 150px; border-radius: 50%; margin: 0 auto 1rem; display: grid; place-items: center;
  background: conic-gradient(var(--ring) calc(var(--pct)*1%), var(--card-2) 0); position: relative; }
.grade-ring::after { content: ""; position: absolute; inset: 12px; border-radius: 50%; background: var(--bg); }
.grade-ring .inner { position: relative; z-index: 1; text-align: center; }
.grade-ring .letter { font-size: 2.6rem; font-weight: 800; line-height: 1; }
.grade-ring .pct { color: var(--muted); font-size: .9rem; }
.result-line { text-align: center; color: var(--muted); margin-bottom: 1.6rem; }
.breakdown { display: grid; gap: .5rem; margin-bottom: 1.6rem; }
.bd-row { display: grid; grid-template-columns: 70px 1fr 60px; align-items: center; gap: .7rem; font-size: .85rem; }
.bd-bar { height: 8px; background: var(--card-2); border-radius: 5px; overflow: hidden; }
.bd-bar span { display: block; height: 100%; background: var(--fc, var(--accent)); }
.wrong-item { background: var(--card); border: 1px solid var(--border); border-left: 4px solid var(--red); border-radius: 10px; padding: .8rem 1rem; margin-bottom: .6rem; }
.wrong-item .wq { font-weight: 600; margin-bottom: .3rem; }
.wrong-item .wa { font-size: .86rem; }
.wrong-item .wa .yours { color: var(--red); }
.wrong-item .wa .right { color: var(--green); }

/* config */
.config-row { display: flex; flex-wrap: wrap; gap: .5rem; margin: .5rem 0 1.2rem; }
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 10px; overflow: hidden; }
.seg button { background: var(--card); color: var(--muted); border: none; padding: .5rem .9rem; font-weight: 600; }
.seg button.active { background: var(--accent); color: #0b1020; }
.filechk { display: flex; flex-wrap: wrap; gap: .4rem; }
.filechk label { display: inline-flex; align-items: center; gap: .35rem; background: var(--card); border: 1px solid var(--border); border-radius: 8px; padding: .35rem .6rem; font-size: .85rem; cursor: pointer; }
.filechk input { accent-color: var(--accent); }

/* image lightbox */
.lightbox { position: fixed; inset: 0; background: rgba(0,0,0,.85); z-index: 100; display: grid; place-items: center; padding: 2rem; cursor: zoom-out; }
.lightbox img { max-width: 96vw; max-height: 92vh; border-radius: 8px; }

.empty { color: var(--muted); font-style: italic; padding: 1rem 0; }

/* Stats */
.stats-table { width: 100%; border-collapse: collapse; font-size: .9rem; }
.stats-table th { color: var(--muted); font-weight: 600; text-align: center; padding: .5rem .6rem; border-bottom: 1px solid var(--border); font-size: .82rem; }
.stats-table td { text-align: center; padding: .55rem .6rem; border-bottom: 1px solid var(--border); }
.stats-table tr:last-child td { border-bottom: none; }
.stat-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; margin-bottom: 1.1rem; }
.kv { display: flex; justify-content: space-between; padding: .3rem 0; border-bottom: 1px solid var(--border); font-size: .9rem; }
.kv:last-child { border-bottom: none; }
.kv span { color: var(--muted); }
.wk-grid { display: grid; gap: 1rem; }
.wk-group .wk-topic { font-weight: 700; margin-bottom: .4rem; font-size: .9rem; }
.wk-cell { display: grid; grid-template-columns: 90px 1fr 48px; align-items: center; gap: .6rem; margin-bottom: .35rem; }
.wk-name { font-size: .82rem; font-weight: 600; }
.wk-pct { text-align: right; font-size: .82rem; color: var(--muted); }
.mini-bar { display: inline-block; width: 90px; height: 7px; background: var(--card-2); border-radius: 4px; overflow: hidden; vertical-align: middle; margin-right: .4rem; }
.mini-bar span { display: block; height: 100%; }
.mini-pct { font-size: .82rem; color: var(--muted); }

@media (max-width: 800px) {
  .mode-grid { grid-template-columns: 1fr; }
  .repaso-cols { grid-template-columns: 1fr; }
}