/* Cozy, calm, study-friendly theme */
:root {
  --bg: #f7f4ef;          /* warm beige */
  --card: #ffffff;
  --text: #2b2b2b;
  --muted: #6b6b6b;
  --primary: #4b6b8a;     /* muted blue */
  --primary-contrast: #ffffff;
  --accent: #9bb7cf;
  --border: #e7e2da;
  --success: #2e7d32;
  --error: #b00020;
  --tint: 155, 183, 207;  /* rgb tuple used for soft tints */

  /* Motion & radii */
  --radius: 16px;
  --radius-sm: 12px;
  --elev: 0 1px 2px rgba(0,0,0,0.03), 0 10px 30px rgba(0,0,0,0.04);
  --easing: cubic-bezier(.22,.61,.36,1);
  --speed-fast: 160ms;
  --speed-mid: 220ms;
}

[data-theme="dark"] {
  --bg: #141517;
  --card: #1c1e21;
  --text: #e6e6e6;
  --muted: #a9a9a9;
  --primary: #86a7c4;
  --primary-contrast: #121314;
  --accent: #3a5168;
  --border: #2a2d31;
  --success: #6ccf78;
  --error: #ff5c6c;
  --tint: 58, 81, 104;
}

/* Palettes (light) */
:root[data-palette="cozy"] { /* default, already set via variables above */ }
:root[data-palette="ocean"] { --primary: #2a7fab; --accent: #8ecae6; --tint: 142, 202, 230; }
:root[data-palette="forest"] { --primary: #2e7d32; --accent: #a5d6a7; --tint: 165, 214, 167; }
:root[data-palette="plum"] { --primary: #7b5ea7; --accent: #c8b5e8; --tint: 200, 181, 232; }
:root[data-palette="solar"] { --primary: #b58900; --accent: #f1d38a; --tint: 241, 211, 138; }

/* Palettes (dark) */
[data-theme="dark"][data-palette="ocean"] { --primary: #7fc3e1; --accent: #2a6f8a; --tint: 47, 104, 138; }
[data-theme="dark"][data-palette="forest"] { --primary: #79d68c; --accent: #2a6230; --tint: 42, 98, 48; }
[data-theme="dark"][data-palette="plum"] { --primary: #c9a6ff; --accent: #5b3d7a; --tint: 91, 61, 122; }
[data-theme="dark"][data-palette="solar"] { --primary: #ffd166; --accent: #8b6a00; --tint: 139, 106, 0; }

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  line-height: 1.5;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: background-color var(--speed-mid) var(--easing), color var(--speed-mid) var(--easing);
}

.app-header, .app-footer {
  max-width: 900px;
  margin: 0 auto;
  padding: 16px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.app-header h1 {
  margin: 0;
  font-weight: 700;
  letter-spacing: 0.2px;
}

.theme-toggle { display: flex; align-items: center; gap: 14px; }
.toggle-group { display: inline-flex; align-items: center; gap: 6px; }
.palette-group { display: inline-flex; align-items: center; gap: 6px; }
.palette-select {
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
}

.container {
  max-width: 900px;
  width: 100%;
  margin: 0 auto;
  padding: 0 20px 24px;
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Center cards and make content tidy */
.card {
  width: 100%;
  max-width: 760px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--elev);
}

.hidden { display: none; }

/* Typography */
.card h2 { margin: 4px 0 12px; text-align: center; }
.card p { margin: 8px 0; }

.field { margin: 14px 0; }
.field label { display: block; font-size: 14px; color: var(--muted); margin-bottom: 6px; text-align: center; }
.field select, .field input[type="text"], .field input[type="number"], .field textarea {
  width: 100%;
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
}
.field.inline { display: flex; align-items: center; gap: 8px; justify-content: center; }

.checkbox { display: inline-flex; align-items: center; gap: 8px; cursor: pointer; }

.actions { display: flex; gap: 10px; margin-top: 12px; justify-content: center; }

.btn {
  padding: 10px 16px;
  background: #eae7e2;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: transform var(--speed-fast) var(--easing), background var(--speed-mid) var(--easing), box-shadow var(--speed-mid) var(--easing), opacity var(--speed-mid) var(--easing);
  box-shadow: 0 0 0 rgba(0,0,0,0);
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 6px 14px rgba(0,0,0,0.08); }
.btn:active { transform: translateY(0px) scale(0.985); }

.btn.primary {
  background: var(--primary);
  color: var(--primary-contrast);
  border-color: transparent;
}

/* Dark mode: ensure readable text on light button backgrounds without affecting primary or subtle buttons */
[data-theme="dark"] .btn:not(.primary):not(.subtle) { color: #121314; }

.btn.subtle { background: transparent; }

.hint { color: var(--muted); font-size: 13px; text-align: center; }

.quiz-header { display: flex; justify-content: center; align-items: center; gap: 12px; margin-bottom: 8px; }
.progress { color: var(--muted); font-size: 14px; }
.cooldown { color: var(--muted); font-size: 12px; }

.question-meta { color: var(--muted); font-size: 13px; margin-top: 6px; text-align: center; }
.question-text { font-size: 22px; margin: 12px 0 10px; text-align: center; }
.question-image { display: flex; justify-content: center; }
.question-image img { max-width: 100%; border-radius: var(--radius-sm); border: 1px solid var(--border); }

.answer-area { display: grid; gap: 10px; margin: 12px auto; max-width: 680px; }
.option {
  display: flex; align-items: center; gap: 10px; padding: 12px 14px; border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; background: transparent;
  transition: background var(--speed-mid) var(--easing), transform var(--speed-fast) var(--easing), border-color var(--speed-mid) var(--easing), box-shadow var(--speed-mid) var(--easing);
  -webkit-tap-highlight-color: transparent;
}
.option input { transform: scale(1.15); }
@media (hover: hover) and (pointer: fine) {
  .option:hover { background: rgba(var(--tint), 0.15); }
}
@media (hover: none) {
  .option:hover { background: transparent; }
}
.option:active { transform: scale(0.995); }
/* Keyboard-only focus highlight (no highlight from programmatic focus or touch) */
@supports selector(:has(*)) {
  .kbd-nav .option:has(input:focus-visible) { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(var(--tint), 0.25); }
}
/* Fallback: visible outline on the input itself when using keyboard */
.option input:focus-visible { outline: 2px solid rgba(var(--tint), 0.45); outline-offset: 2px; border-radius: 4px; }

.feedback { margin-top: 10px; font-weight: 700; text-align: center; opacity: 0; transform: translateY(4px); transition: opacity var(--speed-mid) var(--easing), transform var(--speed-mid) var(--easing); }
.feedback.show { opacity: 1; transform: translateY(0); }
.feedback.ok { color: var(--success); }
.feedback.bad { color: var(--error); }

.explanation { margin-top: 10px; border-top: 1px dashed var(--border); padding-top: 10px; }
.explanation-image { margin-top: 8px; display: flex; justify-content: center; }
.explanation-image img { max-width: 100%; border-radius: var(--radius-sm); border: 1px solid var(--border); }

/* Tap-anywhere hint pulse */
.hint.pulse { animation: pulse 1.6s var(--easing) infinite; }
@keyframes pulse { 0%,100% { opacity: .6 } 50% { opacity: .9 } }

/* Screen/card enter animations */
.enter { animation: fadeInUp var(--speed-mid) var(--easing); }
.enter-soft { animation: fadeIn var(--speed-mid) var(--easing); }
@keyframes fadeInUp { from { opacity: 0; transform: translateY(10px) } to { opacity: 1; transform: translateY(0) } }
@keyframes fadeIn { from { opacity: 0 } to { opacity: 1 } }

/* Toggle switch */
.switch { position: relative; display: inline-block; width: 44px; height: 24px; }
.switch input { opacity: 0; width: 0; height: 0; }
.slider { position: absolute; cursor: pointer; top: 0; left: 0; right: 0; bottom: 0; background-color: #ccc; transition: .2s; border-radius: 999px; }
.slider:before { position: absolute; content: ""; height: 18px; width: 18px; left: 3px; bottom: 3px; background-color: white; transition: .2s; border-radius: 50%; }
input:checked + .slider { background-color: var(--primary); }
input:checked + .slider:before { transform: translateX(20px); }

.toggle-label { font-size: 13px; color: var(--muted); margin-left: 6px; }

/* Additional UI for presets/custom choose screen */
.pane { margin-top: 12px; }
.list { display: grid; gap: 10px; margin: 12px 0; }
.item.btn.selected { border-color: var(--primary); background: rgba(155, 183, 207, 0.2); }

/* Responsive */
@media (max-width: 640px) {
  .app-header, .app-footer, .container { padding: 12px; }
  .card { padding: 18px; border-radius: 14px; }
  .question-text { font-size: 20px; }
}