:root {
  --desk: #1b1712;
  --panel: #241f18;
  --paper: #f4ead6;
  --paper-2: #ebe1cc;
  --ink: #1c1712;
  --muted: #6b5f50;
  --rule: #d7cbb3;
  --mark: #9d2f1a;
  --mark-soft: #f0d6cc;
  --ok: #1f5b42;
  --ok-soft: #d7eadf;
  --gold: #a67c32;
  --chip: #efe4ce;
}

* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: "IBM Plex Sans", sans-serif;
  background:
    radial-gradient(1200px 500px at 0% 0%, #2c2419 0%, transparent 50%),
    var(--desk);
  color: var(--paper);
}
button { -webkit-tap-highlight-color: transparent; }

#app { display: grid; grid-template-columns: 300px 1fr; min-height: 100vh; }

.sidebar {
  background: var(--panel);
  border-right: 1px solid #3a3226;
  padding: 28px 18px 48px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
}
.brand {
  font-family: Newsreader, serif;
  font-size: 28px;
  letter-spacing: 0.04em;
  margin: 0 0 4px;
}
.brand span { color: var(--gold); }
.tagline {
  color: #b7a78d;
  font-size: 12.5px;
  line-height: 1.45;
  margin: 0 0 28px;
}
.nav-label {
  font-family: "IBM Plex Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #8a7b66;
  margin: 0 0 10px;
}
.nav-item {
  width: 100%;
  text-align: left;
  background: transparent;
  border: 0;
  color: #ddd1bb;
  padding: 9px 10px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  gap: 10px;
  align-items: baseline;
  font: inherit;
}
.nav-item:hover { background: #312a21; }
.nav-item.active { background: #3b3126; color: #fff8ea; }
.nav-item .num {
  font-family: "IBM Plex Mono", monospace;
  font-size: 11px;
  color: var(--gold);
  width: 22px;
  flex: none;
}
.nav-item .ttl { font-size: 13.5px; }
.progress-mini {
  margin-top: 22px;
  padding: 12px;
  background: #1b1712;
  border: 1px solid #3a3226;
  border-radius: 10px;
  color: #cbbfa8;
  font-size: 12px;
}

.main { padding: 36px 48px 80px; }
.sheet {
  max-width: 920px;
  background: var(--paper);
  color: var(--ink);
  border-radius: 6px;
  box-shadow: 0 24px 60px rgba(0,0,0,.35);
  overflow: hidden;
}
.sheet-head {
  padding: 36px 40px 28px;
  border-bottom: 1px solid var(--rule);
  background:
    linear-gradient(180deg, #f7f0e0, var(--paper));
}
.kicker {
  font-family: "IBM Plex Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--mark);
  margin: 0 0 8px;
}
.sheet-head h1 {
  font-family: Newsreader, serif;
  font-size: 40px;
  font-weight: 600;
  margin: 0 0 10px;
  letter-spacing: -0.02em;
}
.lede { margin: 0; color: var(--muted); font-size: 16px; line-height: 1.55; max-width: 62ch; }
.sheet-body { padding: 8px 40px 40px; }

.method {
  margin: 24px 0;
  padding: 18px 20px;
  background: var(--paper-2);
  border-left: 3px solid var(--gold);
}
.method h2 {
  font-family: Newsreader, serif;
  font-size: 22px;
  margin: 0 0 10px;
}
.method ol, .method ul { margin: 0; padding-left: 18px; }
.method li { margin: 6px 0; line-height: 1.5; }
.catalog {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 14px;
}
.cat {
  background: #fffaf0;
  border: 1px solid var(--rule);
  padding: 12px 14px;
  font-size: 13.5px;
  line-height: 1.45;
}
.cat b { display: block; font-family: "IBM Plex Mono", monospace; font-size: 11px; color: var(--mark); margin-bottom: 4px; letter-spacing: 0.04em; }

.toolbar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 18px 0 6px;
}
.btn {
  border: 1px solid #c9bba0;
  background: #fffaf0;
  color: var(--ink);
  font: inherit;
  font-size: 13px;
  padding: 8px 12px;
  border-radius: 999px;
  cursor: pointer;
}
.btn:hover { border-color: var(--ink); }
.btn.primary { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn.danger { background: var(--mark); color: white; border-color: var(--mark); }
.chip {
  font-family: "IBM Plex Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 999px;
  background: var(--chip);
  color: #5c4e3b;
}
.chip.fondasi { background: #e7efe4; color: #215338; }
.chip.seleksi { background: #efe6c8; color: #6b4e10; }
.chip.brutal { background: var(--mark-soft); color: var(--mark); }
.chip.otb { background: #e4e0f4; color: #3d2f78; }

.q {
  padding: 22px 0;
  border-bottom: 1px dashed var(--rule);
}
.q-top { display: flex; justify-content: space-between; gap: 12px; align-items: center; margin-bottom: 10px; }
.q-id { font-family: "IBM Plex Mono", monospace; font-size: 12px; color: var(--muted); }
.stem { font-size: 18px; line-height: 1.45; margin: 0 0 14px; font-family: Newsreader, serif; }
.stem p { margin: 0 0 8px; }
.options { display: grid; gap: 8px; margin: 0 0 14px; }
.opt {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 10px 12px;
  border: 1px solid var(--rule);
  background: #fffaf0;
  cursor: pointer;
  text-align: left;
  font: inherit;
  color: inherit;
  width: 100%;
}
.opt:hover { border-color: #b9a888; }
.opt.picked { border-color: var(--ink); background: #efe6d0; }
.opt.correct { border-color: var(--ok); background: var(--ok-soft); }
.opt.wrong { border-color: var(--mark); background: var(--mark-soft); }
.opt .letter {
  font-family: "IBM Plex Mono", monospace;
  font-weight: 500;
  width: 18px;
  flex: none;
}
.visual {
  background: #fffaf0;
  border: 1px solid var(--rule);
  padding: 16px;
  margin: 0 0 14px;
  overflow-x: auto;
}
.visual svg { display: block; margin: 0 auto; }

.answer {
  display: none;
  margin-top: 12px;
  background: #fffaf0;
  border: 1px solid var(--rule);
  padding: 16px 18px;
}
.answer.open { display: block; }
.answer h3 {
  font-family: "IBM Plex Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin: 16px 0 6px;
  color: var(--mark);
}
.answer h3:first-child { margin-top: 0; }
.answer p, .answer li { line-height: 1.55; font-size: 14.5px; }
.answer ol { margin: 0; padding-left: 18px; }
.keyline {
  font-family: Newsreader, serif;
  font-size: 22px;
  margin: 0 0 8px;
}

.timer {
  font-family: "IBM Plex Mono", monospace;
  font-size: 20px;
  color: var(--mark);
}
.note { color: var(--muted); font-size: 14px; line-height: 1.5; }

@media (max-width: 920px) {
  #app { grid-template-columns: 1fr; }
  .sidebar {
    position: sticky;
    top: 0;
    z-index: 5;
    height: auto;
    max-height: none;
    padding: calc(12px + env(safe-area-inset-top)) 14px 12px;
    border-right: 0;
    border-bottom: 1px solid #3a3226;
  }
  .tagline, .progress-mini { display: none; }
  .nav-label { margin-bottom: 8px; }
  .sidebar .nav-item { display: none; }
  .sidebar { padding-bottom: 10px; }
  .main { padding: 12px 12px calc(24px + env(safe-area-inset-bottom)); }
  .sheet-head, .sheet-body { padding-left: 16px; padding-right: 16px; }
  .sheet-head { padding-top: 22px; }
  .sheet-head h1 { font-size: 28px; }
  .catalog { grid-template-columns: 1fr; }
  .lede { font-size: 15px; }
  .stem { font-size: 17px; }
  .opt, .btn, .nav-item { min-height: 44px; }
  .opt { padding: 12px 14px; }
  .visual svg { max-width: 100%; height: auto; }
}

.mobile-nav {
  display: none;
}
@media (max-width: 920px) {
  .mobile-nav {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding: 0 0 4px;
    margin: 0 -2px;
  }
  .mobile-nav button {
    flex: none;
    border: 0;
    background: #312a21;
    color: #ddd1bb;
    font: inherit;
    font-size: 13px;
    padding: 10px 12px;
    border-radius: 999px;
    min-height: 40px;
  }
  .mobile-nav button.active {
    background: #efe4ce;
    color: #1c1712;
  }
  .mobile-nav .num {
    font-family: "IBM Plex Mono", monospace;
    font-size: 10px;
    color: var(--gold);
    margin-right: 4px;
  }
  .mobile-nav button.active .num { color: var(--mark); }
}