/* Math Drill — BTWV-style Design */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #ffffff;
  --surface: #f5f5f5;
  --border: #dddddd;
  --text: #1a1a1a;
  --text-sec: #666666;
  --accent: #ff6b35;
  --accent-light: rgba(255, 107, 53, 0.1);
  --success: #00d26a;
  --error: #d63031;
  --gold: #ffd700;
  --radius: 12px;
  --radius-sm: 8px;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  line-height: 1.6;
  min-height: 100dvh;
  padding-bottom: 70px;
  -webkit-overflow-scrolling: touch;
}

/* Dot grid bg */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: radial-gradient(circle, #ccc 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: 0.05;
  pointer-events: none;
  z-index: 0;
}

.page-wrap {
  position: relative;
  z-index: 1;
  max-width: 600px;
  margin: 0 auto;
  padding: 0 20px;
}

/* HEADER */
header {
  border-bottom: 1px solid var(--border);
  padding: 20px 0;
  margin-bottom: 24px;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  text-decoration: none;
  color: var(--text);
}

.logo-icon { color: var(--accent); font-size: 1.2rem; }

nav a {
  color: var(--text-sec);
  text-decoration: none;
  font-size: 0.85rem;
  font-family: 'IBM Plex Mono', monospace;
  transition: color 0.2s;
}

nav a:hover { color: var(--text); }

/* HERO (small) */
.hero-sm {
  text-align: center;
  padding: 20px 0;
  margin-bottom: 16px;
}

.page-title {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.8rem;
  font-weight: 700;
}

/* Points Display */
.points-display,
.shop-points-display {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 8px 20px;
  border-radius: 24px;
}

.points-label { font-size: 1rem; }
.points-value {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-family: 'IBM Plex Mono', monospace;
}
.points-unit { font-size: 0.8rem; color: var(--text-sec); }

/* Cards */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  margin-bottom: 16px;
  position: relative;
  overflow: hidden;
}

.card.correct-flash { animation: flashCorrect 0.5s ease-out; }
.card.wrong-flash { animation: flashWrong 0.5s ease-out; }

@keyframes flashCorrect {
  0%, 100% { background: var(--surface); }
  50% { background: #e8f9f1; }
}
@keyframes flashWrong {
  0%, 100% { background: var(--surface); }
  50% { background: #fce8e8; }
}

/* Buttons */
.btn {
  display: block;
  width: 100%;
  padding: 16px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  font-family: 'IBM Plex Sans', sans-serif;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.btn:active { transform: scale(0.98); }

.btn-primary {
  background: var(--accent);
  color: white;
}

.btn-primary:hover { opacity: 0.9; }

.btn-danger {
  background: var(--error);
  color: white;
}

.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
}

/* Problem Display */
.problem-display {
  font-size: 3.2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
  font-family: 'Space Grotesk', sans-serif;
  letter-spacing: 2px;
}

.diff-label {
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-sec);
  font-family: 'IBM Plex Mono', monospace;
  margin-bottom: 20px;
  margin-top: -8px;
}

#diff-badge {
  color: var(--accent);
  font-weight: 600;
}

/* Problem layout — two column */
.problem-layout {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.problem-main {
  flex: 1;
  min-width: 0;
}

/* Mascot Playground (sidebar) */
.mascot-playground {
  width: 80px;
  flex-shrink: 0;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 6px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  max-height: 340px;
  overflow-y: auto;
}

.playground-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.6rem;
  color: var(--text-sec);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  text-align: center;
}

.playground-mascots {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
}

/* Playground mascot items — sized by tier and level */
.pg-mascot {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  position: relative;
  transition: transform 0.2s;
}

.pg-mascot-img {
  object-fit: contain;
  flex-shrink: 0;
  border-radius: 8px;
}

.pg-mascot-name {
  font-size: 0.45rem;
  font-family: 'IBM Plex Mono', monospace;
  color: var(--text-sec);
  text-align: center;
  line-height: 1.1;
  max-width: 50px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Level-based sizes per tier */
/* Common tier */
.pg-mascot-common-1 .pg-mascot-img { width: 16px; height: 16px; }
.pg-mascot-common-2 .pg-mascot-img { width: 20px; height: 20px; }
.pg-mascot-common-3 .pg-mascot-img { width: 24px; height: 24px; }
.pg-mascot-common-4 .pg-mascot-img { width: 28px; height: 28px; }

/* Uncommon tier */
.pg-mascot-uncommon-1 .pg-mascot-img { width: 18px; height: 18px; }
.pg-mascot-uncommon-2 .pg-mascot-img { width: 22px; height: 22px; }
.pg-mascot-uncommon-3 .pg-mascot-img { width: 27px; height: 27px; }
.pg-mascot-uncommon-4 .pg-mascot-img { width: 32px; height: 32px; }

/* Rare tier */
.pg-mascot-rare-1 .pg-mascot-img { width: 20px; height: 20px; }
.pg-mascot-rare-2 .pg-mascot-img { width: 25px; height: 25px; }
.pg-mascot-rare-3 .pg-mascot-img { width: 30px; height: 30px; }
.pg-mascot-rare-4 .pg-mascot-img { width: 35px; height: 35px; }

/* Epic tier */
.pg-mascot-epic-1 .pg-mascot-img { width: 22px; height: 22px; }
.pg-mascot-epic-2 .pg-mascot-img { width: 27px; height: 27px; }
.pg-mascot-epic-3 .pg-mascot-img { width: 32px; height: 32px; }
.pg-mascot-epic-4 .pg-mascot-img { width: 37px; height: 37px; }

/* Legendary tier */
.pg-mascot-legendary-1 .pg-mascot-img { width: 24px; height: 24px; }
.pg-mascot-legendary-2 .pg-mascot-img { width: 29px; height: 29px; }
.pg-mascot-legendary-3 .pg-mascot-img { width: 34px; height: 34px; }
.pg-mascot-legendary-4 .pg-mascot-img { width: 39px; height: 39px; }

/* Equipped mascot glow */
.pg-mascot.equipped .pg-mascot-img {
  box-shadow: 0 0 0 3px var(--accent), 0 0 12px rgba(255,107,53,0.4);
}

.pg-mascot.equipped .pg-mascot-name {
  color: var(--accent);
  font-weight: 600;
}

/* Level stars in playground */
.pg-mascot-level {
  font-size: 0.5rem;
  color: var(--gold);
  line-height: 1;
}

/* Home mascot center */
.home-mascot-center {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  margin-bottom: 20px;
  min-height: 80px;
  justify-content: center;
}

.home-mascot-img {
  width: 72px;
  height: 72px;
  object-fit: contain;
}

.home-mascot-name {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-sec);
}

.no-mascot-hint {
  font-size: 0.85rem;
  color: var(--text-sec);
  font-style: italic;
}

/* Hint bubble */
.hint-bubble {
  background: var(--accent-light);
  border: 1px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 10px 16px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--accent);
  margin-bottom: 16px;
}

/* Answer Input */
.answer-input {
  width: 100%;
  padding: 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  font-size: 1.8rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
  font-family: 'Space Grotesk', sans-serif;
  outline: none;
  transition: border-color 0.2s;
}

.answer-input:focus { border-color: var(--accent); }
.answer-input::placeholder { color: var(--text-sec); font-weight: 400; }
.answer-input::-webkit-outer-spin-button,
.answer-input::-webkit-inner-spin-button { -webkit-appearance: none; }

/* Result */
.result-icon { font-size: 3.5rem; text-align: center; margin-bottom: 8px; }

.result-text {
  font-size: 1.6rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 8px;
  font-family: 'Space Grotesk', sans-serif;
}

.result-text.correct { color: var(--success); }
.result-text.wrong { color: var(--error); }
.result-text.saved { color: var(--accent); }
.result-text.bonus { color: var(--gold); }

.points-change {
  font-size: 1.2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
  font-family: 'IBM Plex Mono', monospace;
  animation: popIn 0.4s ease-out;
}

.points-change.positive { color: var(--accent); }
.points-change.negative { color: var(--error); }

@keyframes popIn {
  0% { opacity: 0; transform: scale(0.7); }
  60% { transform: scale(1.1); }
  100% { opacity: 1; transform: scale(1); }
}

.correct-answer {
  text-align: center;
  color: var(--text-sec);
  margin-bottom: 20px;
  font-size: 1rem;
}

.correct-answer span {
  color: var(--success);
  font-weight: 700;
  font-family: 'IBM Plex Mono', monospace;
}

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 16px;
  text-align: center;
}

.stat-icon { font-size: 1.4rem; margin-bottom: 6px; }
.stat-value { font-size: 1.8rem; font-weight: 700; font-family: 'Space Grotesk', sans-serif; }
.stat-label { font-size: 0.75rem; color: var(--text-sec); margin-top: 2px; }

/* History */
.history-section { margin-bottom: 24px; }
.section-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  color: var(--text-sec);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 14px;
}
.history-list { list-style: none; }
.history-list li {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin-bottom: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.9rem;
}
.history-empty { color: var(--text-sec); text-align: center; padding: 20px !important; }
.history-item .problem { font-family: 'IBM Plex Mono', monospace; font-weight: 600; font-size: 0.85rem; }
.history-item .result-icon { font-size: 1.1rem; }
.history-left { display: flex; flex-direction: column; gap: 2px; }
.solve-time { font-size: 0.75rem; color: var(--text-sec); }

/* Settings */
.settings-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 16px;
}

.settings-heading {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-sec);
  font-size: 0.75rem;
}

.setting-hint {
  font-size: 0.8rem;
  color: var(--accent);
  margin-top: 10px;
  text-align: center;
}

/* Slider */
.slider-container { margin-bottom: 8px; }
.slider-labels {
  display: flex;
  justify-content: space-between;
  margin-bottom: 12px;
  font-size: 0.8rem;
  color: var(--text-sec);
}

.slider {
  width: 100%;
  height: 6px;
  -webkit-appearance: none;
  appearance: none;
  background: var(--border);
  border-radius: 3px;
  outline: none;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
}

/* Toggle */
.toggle-list { display: flex; flex-direction: column; }
.toggle-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
}
.toggle-item:last-child { border-bottom: none; }
.toggle-item input { display: none; }
.toggle-switch {
  width: 44px;
  height: 26px;
  background: var(--border);
  border-radius: 13px;
  position: relative;
  transition: background 0.3s;
  flex-shrink: 0;
}
.toggle-switch::after {
  content: '';
  position: absolute;
  width: 22px;
  height: 22px;
  background: white;
  border-radius: 50%;
  top: 2px;
  left: 2px;
  transition: transform 0.3s;
  box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}
.toggle-item input:checked + .toggle-switch { background: var(--accent); }
.toggle-item input:checked + .toggle-switch::after { transform: translateX(18px); }

/* ================= */
/* MASCOT SHOP       */
/* ================= */

.mascot-cards-container {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-bottom: 20px;
}

.shop-tier-header {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.7rem;
  font-weight: 500;
  padding: 10px 12px;
  margin-top: 10px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-sec);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.mascot-tier-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  padding: 8px 0;
}

.mascot-card {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 14px;
  text-align: center;
  position: relative;
  transition: border-color 0.2s, transform 0.2s;
}

.mascot-card:active { transform: scale(0.98); }

.mascot-card.tier-common { border-color: rgba(46, 204, 113, 0.25); }
.mascot-card.tier-uncommon { border-color: rgba(52, 152, 219, 0.25); }
.mascot-card.tier-rare { border-color: rgba(155, 89, 182, 0.3); }
.mascot-card.tier-epic { border-color: rgba(230, 126, 34, 0.35); }
.mascot-card.tier-legendary { border-color: rgba(241, 196, 15, 0.4); }

.mascot-card.equipped { border-color: var(--accent) !important; }

.mascot-card-img {
  width: 68px;
  height: 68px;
  object-fit: contain;
  margin-bottom: 8px;
}

.mascot-level {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: 0.65rem;
  color: var(--accent);
  font-family: 'IBM Plex Mono', monospace;
}

.mascot-name {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 2px;
}

.mascot-desc {
  font-size: 0.7rem;
  color: var(--text-sec);
  margin-bottom: 6px;
  line-height: 1.3;
}

.mascot-ability {
  font-size: 0.72rem;
  color: var(--accent);
  margin-bottom: 8px;
  font-family: 'IBM Plex Mono', monospace;
}

.mascot-cost {
  font-size: 0.72rem;
  color: var(--text-sec);
  margin-bottom: 10px;
  font-family: 'IBM Plex Mono', monospace;
}

.mascot-buttons {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

/* Mascot buttons */
.btn-mascot {
  padding: 8px 10px;
  border: none;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  font-family: 'IBM Plex Sans', sans-serif;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.btn-mascot:active { transform: scale(0.95); }

.btn-mascot.buy { background: var(--accent); color: white; }
.btn-mascot.buy.disabled { background: var(--border); color: var(--text-sec); cursor: not-allowed; }
.btn-mascot.equipped { background: var(--accent); color: white; }
.btn-mascot { background: var(--bg); color: var(--text); border: 1px solid var(--border); }
.btn-mascot.upgrade { background: rgba(0,210,106,0.12); color: var(--success); border: 1px solid rgba(0,210,106,0.3); }
.btn-mascot.upgrade.disabled { background: var(--bg); color: var(--text-sec); border-color: var(--border); cursor: not-allowed; }
.btn-mascot.maxed { background: linear-gradient(135deg, #ffd700, #f39c12); color: #1a1a1a; font-weight: 700; }

/* Bottom Nav */
.bottom-nav {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  background: white;
  display: flex;
  justify-content: space-around;
  padding: 8px 0;
  border-top: 1px solid var(--border);
  z-index: 100;
}

.nav-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  padding: 6px 16px;
  background: none;
  border: none;
  color: var(--text-sec);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: color 0.2s;
}

.nav-btn.active { color: var(--accent); }
.nav-btn:hover { color: var(--text); }
.nav-icon { font-size: 1.3rem; }
.nav-label { font-size: 0.7rem; font-family: 'IBM Plex Mono', monospace; }

/* Tabs */
.tab { display: none; }
.tab.active { display: block; }

/* Utility */
.hidden { display: none !important; }

/* Responsive */
@media (max-width: 400px) {
  .mascot-tier-grid { grid-template-columns: 1fr; }
  .problem-display { font-size: 2.6rem; }
}
/* v2 */