:root {
  /* Segment colors — muted, deliberate palette */
  --c1: #c0392b; /* protocol  */
  --c2: #c97d1a; /* subdomain */
  --c3: #8a5a2b; /* domain    */
  --c4: #2e7d4f; /* tld       */
  --c5: #1f7a8c; /* port      */
  --c6: #2c5f8a; /* path      */
  --c7: #6a4c93; /* query     */
  --c8: #a23b72; /* fragment  */

  --bg: #f4f3ef;
  --surface: #ffffff;
  --surface-2: #faf9f6;
  --line: #e2dfd8;
  --line-strong: #cbc7bd;
  --ink: #23211d;
  --ink-dim: #6b675e;
  --accent: #2f4858;
  --accent-soft: #eef1f3;
  --good: #2e7d4f;
  --good-soft: #e8f3ec;
  --bad: #b23b3b;
  --bad-soft: #f6e9e9;
  --radius: 8px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  min-height: 100vh;
  line-height: 1.5;
}

/* ---------- header ---------- */
.site-header {
  max-width: 820px;
  margin: 0 auto;
  padding: 40px 20px 8px;
}
.site-header h1 {
  font-size: 1.7rem;
  font-weight: 650;
  margin: 0;
  letter-spacing: -0.01em;
}
.tagline { color: var(--ink-dim); margin: 6px 0 20px; font-size: 0.98rem; }

.scorebar {
  display: flex;
  gap: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  width: fit-content;
  background: var(--surface);
}
.score-pill {
  padding: 8px 20px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  min-width: 72px;
  border-right: 1px solid var(--line);
}
.score-pill:last-child { border-right: none; }
.score-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-dim); }
.score-value { font-size: 1.15rem; font-weight: 650; }

/* ---------- tabs ---------- */
.tabs {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  max-width: 820px;
  margin: 28px auto 0;
  padding: 0 20px;
  border-bottom: 1px solid var(--line);
}
.tab {
  background: none;
  border: 1px solid transparent;
  border-bottom: none;
  color: var(--ink-dim);
  padding: 9px 16px;
  border-radius: 6px 6px 0 0;
  font-size: 0.92rem;
  cursor: pointer;
  margin-bottom: -1px;
  transition: color 0.15s, background 0.15s;
}
.tab:hover { color: var(--ink); background: var(--surface-2); }
.tab.active {
  color: var(--ink);
  background: var(--surface);
  border-color: var(--line);
  border-bottom-color: var(--surface);
  font-weight: 600;
}

/* ---------- panels ---------- */
main { max-width: 820px; margin: 0 auto; padding: 28px 20px; }
.panel { display: none; }
.panel.active { display: block; }

.panel-intro { color: var(--ink-dim); margin: 0 0 20px; font-size: 0.96rem; }
.prompt-line { font-size: 1.02rem; margin: 20px 0 10px; color: var(--ink); }
.highlight-word { color: var(--accent); font-weight: 600; }

/* ---------- URL stage ---------- */
.url-stage {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 22px;
  font-family: "SFMono-Regular", "Consolas", "Menlo", monospace;
  font-size: clamp(1rem, 3vw, 1.45rem);
  text-align: center;
  word-break: break-all;
  line-height: 2;
  user-select: none;
}
.url-seg {
  position: relative;
  padding: 2px 2px;
  border-radius: 4px;
  transition: background 0.12s, box-shadow 0.12s;
  cursor: pointer;
}
.url-seg.dim { color: var(--ink-dim); opacity: 0.55; }
.url-seg:hover { background: var(--accent-soft); }
.url-seg.active-glow {
  box-shadow: inset 0 -2px 0 0 currentColor;
  background: var(--accent-soft);
}
.url-stage.clickable .url-seg { cursor: pointer; }

.seg-1 { color: var(--c1); }
.seg-2 { color: var(--c2); }
.seg-3 { color: var(--c3); }
.seg-4 { color: var(--c4); }
.seg-5 { color: var(--c5); }
.seg-6 { color: var(--c6); }
.seg-7 { color: var(--c7); }
.seg-8 { color: var(--c8); }
.punct { color: var(--line-strong); cursor: default; }
.punct:hover { background: none; }

.url-seg.flash-good { background: var(--good-soft) !important; box-shadow: inset 0 -2px 0 0 var(--good); }
.url-seg.flash-bad { background: var(--bad-soft) !important; box-shadow: inset 0 -2px 0 0 var(--bad); }

/* ---------- explain card ---------- */
.explain-card {
  display: flex;
  gap: 14px;
  align-items: baseline;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin: 22px 0;
  min-height: 76px;
}
.explain-index {
  font-family: "SFMono-Regular", "Consolas", monospace;
  font-weight: 700;
  color: var(--accent);
  font-size: 0.95rem;
}
.explain-card h3 { margin: 0 0 4px; font-size: 1.05rem; }
.explain-card p { margin: 0; color: var(--ink-dim); font-size: 0.95rem; }

/* ---------- legend ---------- */
.legend {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 6px;
}
.legend-item {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 9px 12px;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--surface);
  font-size: 0.88rem;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}
.legend-item:hover { border-color: var(--line-strong); background: var(--surface-2); }
.legend-dot { width: 11px; height: 11px; border-radius: 2px; flex-shrink: 0; }

/* ---------- choices ---------- */
.choice-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 10px;
  margin: 18px 0;
}
.choice {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  color: var(--ink);
  padding: 14px 16px;
  border-radius: 6px;
  font-size: 0.98rem;
  cursor: pointer;
  text-align: left;
  transition: border-color 0.12s, background 0.12s;
}
.choice:hover:not(:disabled) { border-color: var(--accent); background: var(--surface-2); }
.choice:disabled { cursor: default; }
.choice.correct { background: var(--good-soft); border-color: var(--good); color: var(--good); }
.choice.wrong { background: var(--bad-soft); border-color: var(--bad); color: var(--bad); }

/* ---------- feedback / buttons ---------- */
.feedback {
  min-height: 24px;
  font-size: 0.96rem;
  margin: 8px 0;
}
.feedback.good { color: var(--good); }
.feedback.bad { color: var(--bad); }

.btn {
  display: inline-block;
  margin: 8px 0 0;
  background: var(--accent);
  color: #fff;
  border: 1px solid var(--accent);
  padding: 10px 22px;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s;
}
.btn:hover { opacity: 0.9; }

/* ---------- find mode ---------- */
.find-prompt { margin-bottom: 16px; }
.find-label-pill {
  display: inline-block;
  background: var(--accent-soft);
  border: 1px solid var(--line-strong);
  color: var(--accent);
  padding: 8px 18px;
  border-radius: 6px;
  font-size: 1.05rem;
  font-weight: 650;
}

/* ---------- drag & drop ---------- */
.drag-stage { line-height: 2.6; }
.url-seg.drop-slot {
  outline: 1px dashed var(--line-strong);
  outline-offset: 2px;
  min-width: 18px;
}
.url-seg.drop-slot.drag-over {
  outline: 1px solid var(--accent);
  background: var(--accent-soft);
}
.url-seg.drop-slot.filled { outline: none; }
.slot-tag {
  display: inline-block;
  font-family: -apple-system, "Segoe UI", sans-serif;
  font-size: 0.6em;
  font-weight: 600;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 1px 6px;
  margin-left: 4px;
  vertical-align: middle;
}
.slot-tag.ok { background: var(--good-soft); border-color: var(--good); color: var(--good); }

.term-bank {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 24px 0 12px;
  min-height: 50px;
}
.term-chip {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  padding: 9px 16px;
  border-radius: 6px;
  font-weight: 550;
  font-size: 0.95rem;
  cursor: grab;
  transition: border-color 0.12s, background 0.12s;
  touch-action: none;
}
.term-chip:hover { background: var(--surface-2); }
.term-chip:active { cursor: grabbing; }
.term-chip.dragging { opacity: 0.4; }
.term-chip.placed { display: none; }

.drag-ghost {
  position: fixed;
  z-index: 100;
  pointer-events: none;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  padding: 9px 16px;
  border-radius: 6px;
  font-weight: 550;
  box-shadow: 0 4px 12px rgba(0,0,0,0.12);
}

/* ---------- quiz ---------- */
.quiz-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
}
.quiz-progress { color: var(--ink-dim); font-size: 0.82rem; margin-bottom: 8px; letter-spacing: 0.02em; }
#quiz-question { font-size: 1.15rem; margin: 0 0 4px; font-weight: 600; }
.quiz-result {
  text-align: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px;
}
.quiz-result h2 { font-size: 1.6rem; margin: 0 0 10px; }

/* ---------- toast ---------- */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  background: var(--ink);
  color: var(--bg);
  border: none;
  padding: 10px 20px;
  border-radius: 6px;
  font-weight: 550;
  font-size: 0.9rem;
  z-index: 50;
  opacity: 0;
  transition: transform 0.25s ease, opacity 0.25s;
  pointer-events: none;
}
.toast.show { transform: translateX(-50%) translateY(0); opacity: 1; }

/* ---------- footer ---------- */
.site-footer {
  text-align: center;
  color: var(--ink-dim);
  font-size: 0.82rem;
  padding: 32px 20px;
  border-top: 1px solid var(--line);
  max-width: 820px;
  margin: 20px auto 0;
}

@media (max-width: 480px) {
  .url-stage { line-height: 1.9; }
  .tab { padding: 8px 11px; font-size: 0.85rem; }
}