/* ============ StudyHub — institutional modern ============ */
:root {
  --paper: #f4f5f2;
  --paper-2: #ffffff;
  --ink: #171d26;
  --ink-2: #4a5361;
  --ink-3: #8b93a1;
  --line: #dcdfd9;
  --accent: #2743e3;
  --accent-ink: #1b2fa8;
  --accent-soft: #e7eafc;
  --good: #157a4c;
  --good-soft: #e2f3e9;
  --bad: #b3261e;
  --bad-soft: #fbe7e5;
  --warn: #a06a00;
  --warn-soft: #fdf1d8;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(23, 29, 38, 0.06), 0 6px 24px -8px rgba(23, 29, 38, 0.12);
  --font-display: "Bricolage Grotesque", "Segoe UI", sans-serif;
  --font-body: "Instrument Sans", "Segoe UI", sans-serif;
  --font-mono: "Spline Sans Mono", Consolas, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  background: var(--paper);
  background-image: radial-gradient(rgba(23,29,38,0.045) 1px, transparent 1px);
  background-size: 22px 22px;
  color: var(--ink);
  font-size: 15px;
  line-height: 1.55;
  min-height: 100vh;
}

h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; letter-spacing: -0.02em; line-height: 1.15; }
a { color: var(--accent-ink); text-decoration: none; }
a:hover { text-decoration: underline; }
button { font-family: inherit; cursor: pointer; }
input, select, textarea { font-family: inherit; font-size: inherit; }

/* ---------- layout ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 18px;
  padding: 0 22px; height: 58px;
  background: var(--ink); color: #fff;
}
.topbar .brand {
  font-family: var(--font-display); font-weight: 800; font-size: 19px; letter-spacing: -0.02em;
  color: #fff; display: flex; align-items: center; gap: 9px; white-space: nowrap;
}
.brand-mark {
  width: 24px; height: 24px; border-radius: 6px; background: var(--accent);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 800; color: #fff;
}
.topbar nav { display: flex; gap: 4px; flex: 1; overflow-x: auto; scrollbar-width: none; }
.topbar nav::-webkit-scrollbar { display: none; }
.tabs { scrollbar-width: none; }
.tabs::-webkit-scrollbar { display: none; }
.topbar nav a {
  color: #c8cdd6; padding: 7px 12px; border-radius: 7px; font-weight: 500; font-size: 14px; white-space: nowrap;
}
.topbar nav a:hover { color: #fff; text-decoration: none; background: rgba(255,255,255,0.08); }
.topbar nav a.active { color: #fff; background: var(--accent); }
.topbar .who { font-size: 13px; color: #c8cdd6; white-space: nowrap; }
.topbar .who b { color: #fff; }

.wrap { max-width: 1100px; margin: 0 auto; padding: 30px 22px 80px; }

.page-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 16px; margin-bottom: 22px; flex-wrap: wrap; }
.page-head h1 { font-size: 30px; }
.page-head .sub { color: var(--ink-2); margin-top: 4px; max-width: 60ch; }

/* ---------- cards & panels ---------- */
.panel { background: var(--paper-2); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.panel-pad { padding: 22px; }

.grid { display: grid; gap: 14px; }
.grid.cols-3 { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }

.set-card { padding: 18px; display: flex; flex-direction: column; gap: 8px; transition: transform 0.12s ease, box-shadow 0.12s ease; position: relative; }
.set-card:hover { transform: translateY(-2px); box-shadow: 0 2px 4px rgba(23,29,38,0.08), 0 12px 32px -8px rgba(23,29,38,0.18); }
.set-card h3 { font-size: 17px; }
.set-card h3 a { color: var(--ink); }
.set-card .meta { color: var(--ink-3); font-size: 12.5px; margin-top: auto; }

.badge {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 11.5px; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase;
  padding: 3px 9px; border-radius: 99px; background: var(--accent-soft); color: var(--accent-ink);
  width: fit-content;
}
.badge.neutral { background: #eef0eb; color: var(--ink-2); }
.badge.good { background: var(--good-soft); color: var(--good); }
.badge.bad { background: var(--bad-soft); color: var(--bad); }
.badge.warn { background: var(--warn-soft); color: var(--warn); }

/* ---------- forms ---------- */
label.field { display: block; margin-bottom: 14px; }
label.field > span { display: block; font-weight: 600; font-size: 13px; margin-bottom: 5px; color: var(--ink-2); }
input[type="text"], input[type="password"], input[type="number"], input[type="date"], select, textarea {
  width: 100%; padding: 9px 12px; border: 1px solid var(--line); border-radius: 8px;
  background: #fff; color: var(--ink); outline: none; transition: border 0.12s, box-shadow 0.12s;
}
input:focus, select:focus, textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 9px 18px; border-radius: 8px; border: 1px solid transparent;
  font-weight: 600; font-size: 14px; background: var(--accent); color: #fff;
  transition: background 0.12s, transform 0.05s;
}
.btn:hover { background: var(--accent-ink); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn.ghost:hover { background: #eef0eb; }
.btn.danger { background: var(--bad); }
.btn.small { padding: 5px 12px; font-size: 13px; }

.checks { display: flex; gap: 16px; flex-wrap: wrap; }
.checks label { display: inline-flex; align-items: center; gap: 7px; font-weight: 500; cursor: pointer; }
.checks input { accent-color: var(--accent); width: 16px; height: 16px; }

/* ---------- tables ---------- */
.tbl-scroll { overflow-x: auto; }
table.tbl { width: 100%; border-collapse: collapse; font-size: 14px; }
.tbl th {
  text-align: left; font-size: 11.5px; letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--ink-3); font-weight: 700; padding: 10px 12px; border-bottom: 2px solid var(--line);
  white-space: nowrap;
}
.tbl td { padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: middle; }
.tbl tr:last-child td { border-bottom: none; }
.tbl tbody tr:hover { background: #fafbf8; }
.num { font-family: var(--font-mono); font-size: 13px; }

.score-pill { font-family: var(--font-mono); font-weight: 600; font-size: 13px; padding: 3px 10px; border-radius: 99px; display: inline-block; }
.score-hi { background: var(--good-soft); color: var(--good); }
.score-mid { background: var(--warn-soft); color: var(--warn); }
.score-lo { background: var(--bad-soft); color: var(--bad); }

/* ---------- login ---------- */
.login-shell { min-height: 100vh; display: grid; place-items: center; padding: 24px; }
.login-card { width: 100%; max-width: 400px; padding: 36px; }
.login-card h1 { font-size: 26px; margin-bottom: 4px; }
.login-card .sub { color: var(--ink-2); margin-bottom: 24px; font-size: 14px; }
.login-logo { display: flex; align-items: center; gap: 10px; margin-bottom: 22px; font-family: var(--font-display); font-weight: 800; font-size: 22px; }

/* ---------- tabs ---------- */
.tabs { display: flex; gap: 2px; border-bottom: 2px solid var(--line); margin-bottom: 20px; overflow-x: auto; }
.tabs button {
  background: none; border: none; padding: 10px 16px; font-weight: 600; font-size: 14px;
  color: var(--ink-2); border-bottom: 2px solid transparent; margin-bottom: -2px; white-space: nowrap;
}
.tabs button.active { color: var(--accent-ink); border-bottom-color: var(--accent); }

/* ---------- study guide markdown ---------- */
.md { max-width: 75ch; }
.md h2 { font-size: 21px; margin: 26px 0 10px; padding-bottom: 6px; border-bottom: 1px solid var(--line); }
.md h3 { font-size: 17px; margin: 20px 0 8px; }
.md p { margin: 10px 0; }
.md ul, .md ol { margin: 10px 0 10px 22px; }
.md li { margin: 4px 0; }
.md strong { color: var(--accent-ink); }
.md blockquote { border-left: 3px solid var(--accent); padding: 6px 14px; background: var(--accent-soft); border-radius: 0 8px 8px 0; margin: 12px 0; color: var(--ink-2); }
.md code { font-family: var(--font-mono); font-size: 0.9em; background: #eef0eb; padding: 1px 5px; border-radius: 4px; }

/* ---------- flashcards ---------- */
.fc-stage { display: flex; flex-direction: column; align-items: center; gap: 18px; padding: 10px 0 30px; }
.fc-card {
  width: min(620px, 100%); height: 330px; perspective: 1400px; cursor: pointer; border: none; background: none; padding: 0;
}
.fc-inner {
  position: relative; width: 100%; height: 100%;
  transform-style: preserve-3d; transition: transform 0.45s cubic-bezier(0.4, 0.1, 0.2, 1);
}
.fc-card.flipped .fc-inner { transform: rotateY(180deg); }
.fc-face {
  position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden;
  display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center;
  padding: 34px; border-radius: 16px; border: 1px solid var(--line); background: var(--paper-2); box-shadow: var(--shadow);
}
.fc-face .kicker { position: absolute; top: 16px; left: 20px; font-size: 11px; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3); }
.fc-face.front .content { font-family: var(--font-display); font-size: 26px; font-weight: 700; letter-spacing: -0.01em; }
.fc-face.back { transform: rotateY(180deg); background: var(--ink); color: #f0f2ee; border-color: var(--ink); }
.fc-face.back .kicker { color: #8b93a1; }
.fc-face.back .content { font-size: 17px; line-height: 1.6; max-height: 240px; overflow-y: auto; }
.fc-controls { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; }
.fc-progress { font-family: var(--font-mono); font-size: 13px; color: var(--ink-2); }
.fc-known-bar { display: flex; gap: 3px; width: min(620px, 100%); }
.fc-known-bar i { flex: 1; height: 5px; border-radius: 3px; background: var(--line); }
.fc-known-bar i.known { background: var(--good); }
.fc-known-bar i.unknown { background: var(--bad); }
.fc-known-bar i.current { outline: 2px solid var(--accent); outline-offset: 1px; }

/* ---------- quiz ---------- */
.q-block { padding: 20px 22px; margin-bottom: 14px; }
.q-block .q-num { font-family: var(--font-mono); font-size: 12px; color: var(--ink-3); margin-bottom: 6px; }
.q-block .q-prompt { font-weight: 600; font-size: 16px; margin-bottom: 14px; }
.q-opts { display: flex; flex-direction: column; gap: 8px; }
.q-opt {
  display: flex; align-items: flex-start; gap: 10px; padding: 10px 14px;
  border: 1px solid var(--line); border-radius: 8px; cursor: pointer; transition: border 0.1s, background 0.1s;
}
.q-opt:hover { border-color: var(--accent); background: var(--accent-soft); }
.q-opt input { margin-top: 3px; accent-color: var(--accent); }
.q-opt.sel { border-color: var(--accent); background: var(--accent-soft); }
.q-opt.right { border-color: var(--good); background: var(--good-soft); }
.q-opt.wrong { border-color: var(--bad); background: var(--bad-soft); }

.result-hero { text-align: center; padding: 36px 22px; }
.result-hero .big { font-family: var(--font-display); font-size: 58px; font-weight: 800; letter-spacing: -0.03em; }
.result-hero .big.good { color: var(--good); }
.result-hero .big.mid { color: var(--warn); }
.result-hero .big.bad { color: var(--bad); }

.verdict { font-size: 13px; font-weight: 700; margin-top: 10px; }
.verdict.ok { color: var(--good); }
.verdict.no { color: var(--bad); }
.explain { font-size: 13.5px; color: var(--ink-2); margin-top: 8px; border-top: 1px dashed var(--line); padding-top: 8px; }

/* ---------- stats / admin ---------- */
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 14px; margin-bottom: 22px; }
.stat { padding: 16px 18px; }
.stat .n { font-family: var(--font-display); font-size: 30px; font-weight: 800; letter-spacing: -0.02em; }
.stat .l { font-size: 12px; font-weight: 600; letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-3); }

.filters { display: flex; gap: 10px; flex-wrap: wrap; align-items: flex-end; margin-bottom: 16px; }
.filters label.field { margin-bottom: 0; min-width: 160px; flex: 1; max-width: 230px; }

.matrix-cell { text-align: center; }
.trend { font-family: var(--font-mono); font-size: 11px; }

.sparkline { display: flex; align-items: flex-end; gap: 3px; height: 44px; }
.sparkline i { width: 10px; border-radius: 3px 3px 0 0; background: var(--accent); opacity: 0.85; min-height: 3px; }

/* ---------- misc ---------- */
.empty { text-align: center; padding: 48px 20px; color: var(--ink-3); }
.empty .glyph { font-size: 34px; margin-bottom: 10px; }
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  background: var(--ink); color: #fff; padding: 11px 20px; border-radius: 9px; font-size: 14px;
  box-shadow: var(--shadow); z-index: 100; animation: rise 0.25s ease;
}
.toast.err { background: var(--bad); }
@keyframes rise { from { opacity: 0; transform: translate(-50%, 8px); } to { opacity: 1; transform: translate(-50%, 0); } }

.spin {
  width: 18px; height: 18px; border: 2.5px solid rgba(255,255,255,0.35); border-top-color: #fff;
  border-radius: 50%; animation: spin 0.7s linear infinite; display: inline-block;
}
.spin.dark { border-color: rgba(23,29,38,0.2); border-top-color: var(--ink); }
@keyframes spin { to { transform: rotate(360deg); } }

.working { display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 60px 20px; text-align: center; color: var(--ink-2); }
.working .spin { width: 30px; height: 30px; border-width: 3px; }

.notice { padding: 10px 14px; border-radius: 8px; font-size: 13.5px; margin-bottom: 16px; }
.notice.warn { background: var(--warn-soft); color: var(--warn); border: 1px solid #f0dfb0; }

.drop {
  border: 2px dashed var(--line); border-radius: var(--radius); padding: 30px; text-align: center;
  color: var(--ink-2); transition: border-color 0.12s, background 0.12s; cursor: pointer; background: #fff;
}
.drop.over, .drop:hover { border-color: var(--accent); background: var(--accent-soft); }
.file-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.file-chip { display: inline-flex; align-items: center; gap: 7px; background: #eef0eb; border-radius: 99px; padding: 5px 12px; font-size: 13px; }
.file-chip button { border: none; background: none; color: var(--ink-3); font-size: 15px; line-height: 1; }
.file-chip button:hover { color: var(--bad); }

.reveal { animation: reveal 0.3s ease both; }
@keyframes reveal { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ---------- certificate ---------- */
.certificate {
  background: linear-gradient(135deg, #fbfbf9 0%, #f2f4ee 100%);
  border: 2px solid var(--ink); border-radius: 14px; padding: 10px;
  box-shadow: var(--shadow);
}
.cert-inner {
  border: 1px solid var(--accent); border-radius: 10px; padding: 48px 40px; text-align: center;
  position: relative; background:
    radial-gradient(circle at 12% 12%, var(--accent-soft) 0, transparent 22%),
    radial-gradient(circle at 88% 88%, var(--accent-soft) 0, transparent 22%);
}
.cert-mark { width: 46px; height: 46px; border-radius: 12px; background: var(--accent); color: #fff; font-family: var(--font-display); font-weight: 800; font-size: 26px; display: inline-flex; align-items: center; justify-content: center; margin-bottom: 18px; }
.cert-kicker { font-size: 12px; font-weight: 700; letter-spacing: 0.22em; text-transform: uppercase; color: var(--ink-3); }
.cert-name { font-family: var(--font-display); font-size: 42px; font-weight: 800; letter-spacing: -0.02em; margin: 18px 0 6px; }
.cert-body { color: var(--ink-2); font-size: 15px; }
.cert-course { font-family: var(--font-display); font-size: 24px; font-weight: 700; color: var(--accent-ink); margin: 12px 0 4px; }
.cert-sub { color: var(--ink-2); font-size: 14px; }
.cert-score { margin-top: 20px; font-size: 16px; }
.cert-date { margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--line); color: var(--ink-3); font-size: 13px; display: inline-block; }
@media print {
  .no-print { display: none !important; }
  body { background: #fff; }
  .certificate { border-color: #000; box-shadow: none; }
}

@media (max-width: 700px) {
  .topbar { padding: 0 12px; gap: 10px; }
  .topbar .who { display: none; }
  .wrap { padding: 20px 14px 60px; }
  .page-head h1 { font-size: 24px; }
  .fc-card { height: 280px; }
}