:root {
  --bg: #0f172a;
  --bg-panel: #1e293b;
  --bg-input: #0f172a;
  --border: #334155;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --good: #22c55e;
  --bad: #ef4444;
  --warn: #f59e0b;
  --radius: 10px;
}

html[data-theme="light"] {
  --bg: #f1f5f9;
  --bg-panel: #ffffff;
  --bg-input: #f8fafc;
  --border: #cbd5e1;
  --text: #1e293b;
  --text-dim: #64748b;
  --accent: #4f46e5;
  --accent-hover: #6366f1;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  padding-bottom: 3rem;
  transition: background 0.2s, color 0.2s;
}

.theme-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-panel);
  color: var(--text);
  font-size: 1.2rem;
  cursor: pointer;
  transition: transform 0.15s, background 0.15s;
}

.theme-toggle:hover { transform: scale(1.1); }

.site-header {
  text-align: center;
  padding: 2.5rem 1rem 1.5rem;
}

.site-header h1 {
  margin: 0;
  font-size: 2rem;
}

.tagline {
  color: var(--text-dim);
  margin: 0.5rem 0 0;
}

main {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 1rem;
}

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.panel h2 { margin-top: 1.5rem; }
.panel h2:first-of-type { margin-top: 0; }

.hint {
  color: var(--text-dim);
  font-size: 0.9rem;
  margin-top: -0.25rem;
}

.field {
  margin-bottom: 1rem;
}

.field label {
  display: block;
  font-size: 0.85rem;
  margin-bottom: 0.35rem;
  color: var(--text-dim);
}

input, select {
  width: 100%;
  padding: 0.6rem 0.75rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 1rem;
}

input:focus, select:focus {
  outline: none;
  border-color: var(--accent);
}

.btn, .btn-secondary {
  display: inline-block;
  padding: 0.7rem 1.2rem;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  transition: background 0.15s;
}

.btn {
  background: var(--accent);
  color: #fff;
  width: 100%;
  margin-top: 0.5rem;
}

.btn:hover { background: var(--accent-hover); }

.btn-secondary {
  background: transparent;
  color: var(--accent-hover);
  border: 1px dashed var(--border);
  margin-bottom: 0.75rem;
}

.btn-secondary:hover { border-color: var(--accent); }

.result {
  margin-top: 1.25rem;
  padding: 1rem;
  border-radius: var(--radius);
  font-size: 1.05rem;
  display: none;
}

.result.show { display: block; }
.result.good { background: rgba(34,197,94,0.12); border: 1px solid var(--good); }
.result.bad { background: rgba(239,68,68,0.12); border: 1px solid var(--bad); }
.result.warn { background: rgba(245,158,11,0.12); border: 1px solid var(--warn); }
.result .big { font-size: 1.6rem; font-weight: 700; display: block; margin-bottom: 0.25rem; }

.site-footer {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
  margin-top: 2rem;
}

/* ---------- Class schedule ---------- */
.class-card {
  position: relative;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: 1rem;
}

.class-card .remove {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: transparent;
  border: none;
  color: var(--bad);
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
}

.class-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.class-grid .full { grid-column: 1 / -1; }

.days {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.day-pill {
  flex: 1 1 auto;
  text-align: center;
  padding: 0.4rem 0;
  font-size: 0.85rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-panel);
  color: var(--text-dim);
  cursor: pointer;
  user-select: none;
  transition: all 0.15s;
}

.day-pill.on {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.semester-dates {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.holiday-row {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr auto;
  gap: 0.5rem;
  align-items: end;
  margin-bottom: 0.75rem;
}

.holiday-row label {
  display: block;
  font-size: 0.75rem;
  margin-bottom: 0.25rem;
  color: var(--text-dim);
}

.holiday-row .remove {
  background: transparent;
  border: none;
  color: var(--bad);
  font-size: 1.3rem;
  cursor: pointer;
  padding: 0 0.4rem 0.4rem;
}

@media (max-width: 480px) {
  .class-grid, .semester-dates { grid-template-columns: 1fr; }
  .holiday-row {
    grid-template-columns: 1fr 1fr auto;
    grid-template-areas: "name name remove" "from to remove";
  }
  .holiday-row .h-name { grid-area: name; }
  .holiday-row .h-from-wrap { grid-area: from; }
  .holiday-row .h-to-wrap { grid-area: to; }
  .holiday-row .remove { grid-area: remove; align-self: center; }
}