/* ============================================================
   100 MCQ — Nothing-inspired design system
   Monochrome canvas, Space Grotesk + Space Mono + Doto,
   dark (OLED) and light (paper) modes, flat surfaces only.
   ============================================================ */

/* ---------- tokens ---------- */
:root {
  --black: #000000;
  --surface: #111111;
  --surface-raised: #1A1A1A;
  --border: #222222;
  --border-visible: #333333;
  --text-disabled: #666666;
  --text-secondary: #999999;
  --text-primary: #E8E8E8;
  --text-display: #FFFFFF;

  --accent: #D71921;
  --accent-subtle: rgba(215, 25, 33, 0.15);
  --success: #4A9E5C;
  --warning: #D4A843;

  --font-sans: "Space Grotesk", "DM Sans", system-ui, sans-serif;
  --font-mono: "Space Mono", "JetBrains Mono", monospace;
  --font-doto: "Doto", "Space Mono", monospace;
}

[data-theme="light"] {
  --black: #F5F5F5;
  --surface: #FFFFFF;
  --surface-raised: #F0F0F0;
  --border: #E8E8E8;
  --border-visible: #CCCCCC;
  --text-disabled: #999999;
  --text-secondary: #666666;
  --text-primary: #1A1A1A;
  --text-display: #000000;
}

/* ---------- base ---------- */
* { box-sizing: border-box; margin: 0; padding: 0; }

html { height: 100%; }

body {
  background: var(--black);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  transition: background 200ms ease-out, color 200ms ease-out;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
button:disabled { cursor: default; }

::selection { background: var(--text-display); color: var(--black); }

:focus-visible { outline: 1px solid var(--text-secondary); outline-offset: 2px; }

.label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
}

/* ---------- layout ---------- */
.app { display: flex; min-height: 100vh; }

.main {
  flex: 1;
  min-width: 0;
  max-width: 880px;
  width: 100%;
  margin: 0 auto;
  padding: 64px 48px 120px;
}

/* ---------- sidebar ---------- */
.sidebar {
  width: 248px;
  flex-shrink: 0;
  height: 100vh;
  position: sticky;
  top: 0;
  display: flex;
  flex-direction: column;
  padding: 24px 14px 20px;
  border-right: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 4px 10px 26px;
  text-align: left;
}
.brand-mark {
  font-family: var(--font-doto);
  font-size: 38px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--text-display);
}
.brand-unit {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--text-secondary);
}

.nav { flex: 1; overflow-y: auto; display: flex; flex-direction: column; gap: 2px; }
.nav-sec { margin: 18px 10px 8px; }

.nav-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px 10px 10px 12px;
  border-left: 2px solid transparent;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-disabled);
  text-align: left;
  transition: color 150ms ease-out, border-color 150ms ease-out;
}
.nav-item:hover { color: var(--text-primary); }
.nav-item.active { color: var(--text-display); border-left-color: var(--accent); }
.nav-item.locked { opacity: 0.55; }

.nav-score { font-size: 11px; color: var(--text-secondary); flex-shrink: 0; }
.nav-score.is-done { color: var(--success); }
.nav-tag {
  flex-shrink: 0;
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--text-disabled);
  border: 1px solid var(--border-visible);
  border-radius: 999px;
  padding: 2px 8px;
}
.nav-item.active .nav-tag { color: var(--text-display); border-color: var(--text-secondary); }

.sidebar-foot {
  margin-top: 24px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 0 4px;
}
.foot-meta { text-align: center; }

/* segmented control (theme toggle) */
.seg {
  display: flex;
  border: 1px solid var(--border-visible);
  border-radius: 999px;
  padding: 3px;
  gap: 2px;
}
.seg-btn {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  padding: 7px 12px;
  border-radius: 999px;
  color: var(--text-secondary);
  transition: background 150ms ease-out, color 150ms ease-out;
}
.seg-btn:hover { color: var(--text-primary); }
.seg-btn.active { background: var(--text-display); color: var(--black); }

/* ---------- buttons / tags ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 12px 24px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  transition: background 150ms ease-out, color 150ms ease-out, border-color 150ms ease-out, opacity 150ms ease-out;
}
.btn.primary { background: var(--text-display); color: var(--black); }
.btn.primary:hover { background: var(--text-primary); }
.btn.primary:disabled { opacity: 0.4; }
.btn.secondary { border: 1px solid var(--border-visible); color: var(--text-primary); }
.btn.secondary:hover { border-color: var(--text-secondary); }
.btn.ghost { color: var(--text-secondary); padding-left: 8px; padding-right: 8px; }
.btn.ghost:hover { color: var(--text-primary); }

.tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border: 1px solid var(--border-visible);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
}

/* ---------- segmented progress bar ---------- */
.progress-seg { display: flex; gap: 2px; }
.progress-seg i {
  flex: 1;
  height: 8px;
  background: var(--border);
  border-radius: 1px;
  transition: background 200ms ease-out;
}
.progress-seg i.on { background: var(--text-display); }
.progress-seg.hero { gap: 3px; }
.progress-seg.hero i { height: 14px; }
.progress-seg.compact { gap: 2px; }
.progress-seg.compact i { height: 6px; }
.progress-seg.good i.on { background: var(--success); }
.progress-seg.warn i.on { background: var(--warning); }
.progress-seg.bad i.on { background: var(--accent); }

/* ---------- panels / stat rows ---------- */
.panel {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 6px 20px;
}
.stat-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.stat-row:last-child { border-bottom: none; }
.stat-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
}
.stat-value {
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--text-display);
}
.stat-value .unit { font-size: 12px; color: var(--text-secondary); margin-left: 2px; }
.stat-value.is-done { color: var(--success); }
.stat-value.is-off { color: var(--text-disabled); }

/* ---------- home / landing ---------- */
.home { display: flex; flex-direction: column; gap: 40px; position: relative; }

.hero-zone {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 18px;
  padding: 40px 0 8px;
}
.dot-grid-subtle {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, var(--border) 1px, transparent 1px);
  background-size: 16px 16px;
  opacity: 0.55;
  pointer-events: none;
}
.hero-zone > *:not(.dot-grid-subtle) { position: relative; }

.hero {
  font-family: var(--font-doto);
  font-size: clamp(64px, 12vw, 96px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--text-display);
}
.hero small {
  font-family: var(--font-mono);
  font-size: 0.28em;
  font-weight: 400;
  letter-spacing: 0.18em;
  color: var(--text-secondary);
  margin-left: 14px;
}
.hero-sub { color: var(--text-secondary); font-size: 15px; max-width: 420px; }

.hero-bar { display: flex; align-items: center; gap: 16px; }
.hero-bar .progress-seg { flex: 1; }
.hero-bar .label { flex-shrink: 0; }

.actions { display: flex; flex-wrap: wrap; gap: 12px; }

.day-list { display: flex; flex-direction: column; }
.day-row {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 13px 6px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  transition: background 150ms ease-out;
}
.day-row:first-child { border-top: 1px solid var(--border); }
.day-row:hover { background: var(--surface); }
.day-row-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-disabled);
  width: 28px;
  flex-shrink: 0;
}
.day-row-name {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-primary);
}
.day-row-status .stat-value { font-size: 14px; }

/* ---------- quiz ---------- */
.quiz { display: flex; flex-direction: column; gap: 24px; max-width: 720px; }

.quiz-head { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.quiz-meta { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.quiz-score { flex-shrink: 0; }

.question {
  font-size: clamp(24px, 4vw, 32px);
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--text-display);
  max-width: 640px;
}

.options { display: flex; flex-direction: column; gap: 12px; }
.option {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 56px;
  padding: 16px 20px;
  border: 1px solid var(--border-visible);
  border-radius: 12px;
  text-align: left;
  color: var(--text-primary);
  transition: border-color 150ms ease-out, opacity 150ms ease-out, background 150ms ease-out;
}
.option:hover { border-color: var(--text-secondary); }
.opt-key {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  min-width: 24px;
  flex-shrink: 0;
}
.opt-text { flex: 1; }

.option.correct {
  border-color: var(--success);
  background: rgba(74, 158, 92, 0.08);
}
.option.correct .opt-key,
.option.correct .opt-text { color: var(--success); }
.option.wrong {
  border-color: var(--accent);
  background: var(--accent-subtle);
}
.option.wrong .opt-key,
.option.wrong .opt-text { color: var(--accent); }
.option.dim { opacity: 0.45; border-color: var(--border); }
.option:disabled { cursor: default; }

.feedback {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 20px;
  border-left: 2px solid var(--text-secondary);
  border-radius: 0 12px 12px 0;
  background: var(--surface);
}
.feedback.is-correct { border-left-color: var(--success); }
.feedback.is-wrong { border-left-color: var(--accent); }
.fb-status { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.08em; }
.fb-status.ok { color: var(--success); }
.fb-status.no { color: var(--accent); }
.fb-answer {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}
.fb-explain { color: var(--text-primary); font-size: 15px; }

.quiz-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.hidden { display: none; }

/* ---------- result ---------- */
.result { display: flex; flex-direction: column; gap: 28px; max-width: 720px; }

.hero-row { display: flex; align-items: flex-end; gap: 48px; flex-wrap: wrap; }
.hero-num {
  font-family: var(--font-doto);
  font-size: 88px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--text-display);
}
.hero-num small {
  font-family: var(--font-mono);
  font-size: 0.28em;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-left: 10px;
}
.hero-side { display: flex; flex-direction: column; gap: 4px; padding-bottom: 10px; }
.acc { font-family: var(--font-mono); font-size: 30px; color: var(--text-display); }
.acc.good { color: var(--success); }
.acc.warn { color: var(--warning); }
.acc.bad { color: var(--accent); }

.cat-row { display: flex; align-items: center; gap: 16px; padding: 12px 0; border-bottom: 1px solid var(--border); }
.cat-row:last-child { border-bottom: none; }
.cat-name {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  width: 90px;
  flex-shrink: 0;
}
.cat-bar { flex: 1; display: flex; gap: 2px; }
.cat-bar i { flex: 1; height: 8px; background: var(--border); border-radius: 1px; }
.cat-bar i.on { background: var(--success); }
.cat-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-primary);
  width: 44px;
  text-align: right;
  flex-shrink: 0;
}

.review { border: 1px solid var(--border); border-radius: 12px; }
.review-item {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
}
.review-item:last-child { border-bottom: none; }
.rev-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-disabled);
  min-width: 28px;
  flex-shrink: 0;
}
.rev-text {
  flex: 1;
  font-size: 14px;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.rev-status { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.06em; flex-shrink: 0; }
.rev-status.ok { color: var(--success); }
.rev-status.no { color: var(--accent); }

/* ---------- empty states ---------- */
.empty {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 18px;
  padding: 72px 0;
  max-width: 560px;
}
.empty > *:not(.dot-grid-subtle) { position: relative; }
.empty-title { font-size: 32px; font-weight: 500; color: var(--text-display); letter-spacing: -0.01em; }
.empty-desc { color: var(--text-disabled); max-width: 440px; }
.empty-bar { width: 100%; }

/* ---------- responsive ---------- */
@media (max-width: 880px) {
  .app { flex-direction: column; }

  .sidebar {
    width: 100%;
    height: auto;
    position: static;
    flex-direction: row;
    align-items: center;
    gap: 16px;
    padding: 12px 16px;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .brand { padding: 0; }
  .brand-mark { font-size: 28px; }
  .nav { flex-direction: row; overflow-x: auto; gap: 4px; flex: 1; }
  .nav-sec { display: none; }
  .nav-item { border-left: none; border-bottom: 2px solid transparent; padding: 8px 10px; white-space: nowrap; }
  .nav-item.active { border-bottom-color: var(--accent); }
  .nav-tag { display: none; }
  .sidebar-foot { flex-direction: row; margin-top: 0; }
  .foot-meta { display: none; }

  .main { padding: 40px 20px 80px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; }
}