/* ── Design tokens ─────────────────────────────────────────── */
:root {
  --bg:            #eeeef5;
  --bg-gradient:   linear-gradient(160deg, #eeeef5 0%, #e4e0f0 50%, #eae6f3 100%);
  --surface:       #ffffff;
  --surface-2:     #f8f8fc;
  --border:        rgba(0,0,0,0.09);
  --border-inner:  rgba(0,0,0,0.04);
  --text:          #0f0f1a;
  --text-muted:    #8888a8;
  --accent:        #3d5cf5;
  --accent-dim:    rgba(61,92,245,0.12);
  --glow:          rgba(100,80,220,0.10);
  --glow-strong:   rgba(100,80,220,0.18);
  --shadow-card:   0 2px 8px rgba(0,0,0,0.07),
                   0 0 0 1px rgba(0,0,0,0.06),
                   0 4px 16px var(--glow);
  --shadow-raised: 0 8px 24px rgba(0,0,0,0.12),
                   0 0 0 1px rgba(0,0,0,0.07),
                   0 8px 32px var(--glow-strong);
  --card-back-bg:  linear-gradient(145deg, #1a2c6e 0%, #2a1d6e 50%, #1e2460 100%);
  --card-back-line:rgba(255,255,255,0.10);
  --accent-gradient: linear-gradient(135deg, var(--accent), #7b4dff);
  --radius-card:   10px;
  --radius-btn:    14px;
  --header-h:      56px;
  --footer-h:      80px;
  --transition:    0.2s ease;

  /* Tier hue accents */
  --tier-low:      #4a8fe7;        /* 1–3: cool blue */
  --tier-low-dim:  rgba(74,143,231,0.10);
  --tier-mid:      #7c5cf5;        /* 5–13: purple */
  --tier-mid-dim:  rgba(124,92,245,0.10);
  --tier-high:     #c25adc;        /* 21–55: warm purple-magenta */
  --tier-high-dim: rgba(194,90,220,0.10);
}

[data-theme="dark"] {
  --bg:            #0d0d1a;
  --bg-gradient:   linear-gradient(160deg, #0d0d1a 0%, #140e28 50%, #0e0e20 100%);
  --surface:       #1f1f35;
  --surface-2:     #262642;
  --border:        rgba(255,255,255,0.10);
  --border-inner:  rgba(255,255,255,0.05);
  --text:          #eeeef8;
  --text-muted:    #7070a0;
  --accent:        #7b93ff;
  --accent-dim:    rgba(123,147,255,0.15);
  --glow:          rgba(120,90,255,0.15);
  --glow-strong:   rgba(120,90,255,0.25);
  --shadow-card:   0 2px 8px rgba(0,0,0,0.5),
                   0 0 0 1px rgba(255,255,255,0.08),
                   0 4px 16px var(--glow);
  --shadow-raised: 0 8px 28px rgba(0,0,0,0.6),
                   0 0 0 1px rgba(255,255,255,0.10),
                   0 8px 32px var(--glow-strong);
  --card-back-bg:  linear-gradient(145deg, #0e1e5a 0%, #1e1050 50%, #121848 100%);
  --card-back-line:rgba(255,255,255,0.08);
  --accent-gradient: linear-gradient(135deg, var(--accent), #a78bfa);

  --tier-low:      #5a9bf0;
  --tier-low-dim:  rgba(90,155,240,0.12);
  --tier-mid:      #9b7fff;
  --tier-mid-dim:  rgba(155,127,255,0.12);
  --tier-high:     #d070e8;
  --tier-high-dim: rgba(208,112,232,0.12);
}

/* ── Reset & base ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  height: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  height: 100%;
  height: 100dvh;
  background: var(--bg-gradient);
  background-color: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  display: flex;
  flex-direction: column;
  transition: background var(--transition), color var(--transition);
  overflow-x: hidden;
  overscroll-behavior-y: contain;
}

/* ── Header ────────────────────────────────────────────────── */
.header {
  position: sticky;
  top: 0;
  z-index: 10;
  height: var(--header-h);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 16px;
  transition: background var(--transition), border-color var(--transition);
}

.header__logo {
  color: var(--accent);
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.header__title {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  flex: 1;
}

.theme-btn {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), border-color var(--transition);
  flex-shrink: 0;
}

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

/* Show sun in dark mode, moon in light mode */
[data-theme="light"] .theme-btn__moon { display: none; }
[data-theme="dark"]  .theme-btn__sun  { display: none; }

/* ── Main / views ──────────────────────────────────────────── */
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding-bottom: calc(var(--footer-h) + 8px);
  min-height: 0;
}

.view {
  position: relative;
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 16px;
  gap: 16px;
}

.view--hidden { display: none; }

.view__hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-weight: 500;
  align-self: flex-start;
  position: absolute;
  top: 16px;
  left: 16px;
}

/* ── Card grid ─────────────────────────────────────────────── */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  width: 100%;
  max-width: 420px;
}

/* ── Grid card ─────────────────────────────────────────────── */
.card {
  --card-accent: var(--tier-mid);
  --card-accent-dim: var(--tier-mid-dim);
  position: relative;
  border-radius: var(--radius-card);
  background: var(--surface);
  box-shadow: var(--shadow-card);
  border: 2px solid var(--border);
  cursor: pointer;
  user-select: none;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    border-color 0.18s ease,
    background var(--transition);
  aspect-ratio: 5 / 7;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  -webkit-tap-highlight-color: transparent;
}

/* Inner border ring for playing-card feel */
.card::after {
  content: '';
  position: absolute;
  inset: 4px;
  border-radius: 7px;
  border: 1px solid var(--border-inner);
  pointer-events: none;
  transition: border-color 0.18s ease;
}

/* Tier colors */
.card[data-tier="low"]  { --card-accent: var(--tier-low);  --card-accent-dim: var(--tier-low-dim); }
.card[data-tier="mid"]  { --card-accent: var(--tier-mid);  --card-accent-dim: var(--tier-mid-dim); }
.card[data-tier="high"] { --card-accent: var(--tier-high); --card-accent-dim: var(--tier-high-dim); }

.card:hover {
  transform: translateY(-3px) rotateX(-2deg) rotateY(2deg);
  box-shadow: var(--shadow-raised);
  border-color: color-mix(in srgb, var(--card-accent) 30%, var(--border));
}

.card:active { transform: translateY(0) scale(0.97); }

.card--selected {
  border-color: var(--card-accent);
  border-width: 3px;
  box-shadow: var(--shadow-raised);
  transform: translateY(-5px) scale(1.03);
  animation: card-border-pulse 2s ease-in-out infinite;
}

.card--selected .card__value,
.card--selected .card__pip {
  animation: card-text-pulse 2s ease-in-out infinite;
}

.card--selected::after {
  border-color: var(--card-accent-dim);
}

@keyframes card-border-pulse {
  0%, 100% { border-color: var(--card-accent); }
  50%      { border-color: color-mix(in srgb, var(--card-accent) 35%, var(--border)); }
}

@keyframes card-text-pulse {
  0%, 100% { opacity: 1; }
  50%      { opacity: 0.5; }
}

/* Corner pips on grid cards */
.card__pip {
  position: absolute;
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--text-muted);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.card__pip--tl { top: 7px; left: 8px; }
.card__pip--br {
  bottom: 7px; right: 8px;
  transform: rotate(180deg);
}

/* Center number on grid card */
.card__value {
  font-size: clamp(1.8rem, calc(14vw - 4px), 3rem);
  font-weight: 800;
  color: var(--card-accent);
  letter-spacing: -0.03em;
  line-height: 1;
  transition: color var(--transition);
}

.card__pip { color: color-mix(in srgb, var(--card-accent) 50%, var(--text-muted)); }

/* ── Flip card (single view) ───────────────────────────────── */
.single-view__wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
}

.flip-card {
  perspective: 1200px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  aspect-ratio: 5 / 7;
  width: 100%;
  max-width: 420px;
  border-radius: var(--radius-card);
  outline-offset: 4px;
}

.flip-card:focus-visible { outline: 2px solid var(--accent); }

.flip-card__inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.55s cubic-bezier(0.4, 0.2, 0.2, 1);
  border-radius: var(--radius-card);
}

.flip-card__inner--flipped { transform: rotateY(180deg); }

.flip-card__face {
  position: absolute;
  inset: 0;
  border-radius: var(--radius-card);
  border: 3px solid var(--border);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  overflow: hidden;
}

/* Card back — the "hidden" face shown initially */
.flip-card__face--back {
  background: var(--card-back-bg);
  background-size: 100% 100%;
  box-shadow: var(--shadow-raised);
  transition: background var(--transition);
}

/* Crosshatch overlay on card back */
.flip-card__face--back::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-image:
    repeating-linear-gradient(
      45deg,
      transparent 0,
      transparent 9px,
      var(--card-back-line) 9px,
      var(--card-back-line) 10px
    ),
    repeating-linear-gradient(
      135deg,
      transparent 0,
      transparent 9px,
      var(--card-back-line) 9px,
      var(--card-back-line) 10px
    );
  pointer-events: none;
}

/* Inset border frame — classic playing card detail */
.flip-card__inset {
  position: absolute;
  inset: 8px;
  border: 1.5px solid rgba(255,255,255,0.15);
  border-radius: 6px;
  pointer-events: none;
  box-shadow: inset 0 0 20px rgba(255,255,255,0.03);
}

/* Card front — the revealed face */
.flip-card__face--front {
  background: var(--surface);
  box-shadow: var(--shadow-raised);
  transform: rotateY(180deg);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
}

/* Inner border on flip card front */
.flip-card__face--front::after {
  content: '';
  position: absolute;
  inset: 6px;
  border-radius: 6px;
  border: 1px solid var(--border-inner);
  pointer-events: none;
}

/* Tier color on flip card */
.flip-card[data-tier="low"]  { --flip-accent: var(--tier-low); }
.flip-card[data-tier="mid"]  { --flip-accent: var(--tier-mid); }
.flip-card[data-tier="high"] { --flip-accent: var(--tier-high); }

/* Corner pips (top-left / bottom-right) on the revealed card */
.flip-card__pip {
  position: absolute;
  font-size: clamp(1.8rem, 6vw, 2.5rem);
  font-weight: 700;
  color: var(--flip-accent, var(--text-muted));
  line-height: 1;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

.flip-card__pip--tl { top: 12px; left: 14px; }
.flip-card__pip--br { bottom: 12px; right: 14px; transform: rotate(180deg); }

/* The large center number */
.flip-card__value {
  font-size: clamp(9rem, 48vw, 14rem);
  font-weight: 900;
  color: var(--flip-accent, var(--text));
  letter-spacing: -0.04em;
  line-height: 1;
  transition: color var(--transition);
  max-width: 90%;
  text-align: center;
}


/* ── Footer / action button ────────────────────────────────── */
.footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--footer-h);
  background: var(--surface);
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 20px;
  padding-bottom: env(safe-area-inset-bottom, 0px);
  transition: background var(--transition), border-color var(--transition);
  z-index: 10;
}

.action-btn {
  width: 100%;
  max-width: 380px;
  height: 52px;
  border-radius: var(--radius-btn);
  border: none;
  background: var(--accent-gradient);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  cursor: pointer;
  transition: opacity 0.15s ease, transform 0.12s ease, filter 0.15s ease;
}

.action-btn:hover:not(:disabled) { filter: brightness(1.1); }
.action-btn:active:not(:disabled) { transform: scale(0.98); }

.action-btn:disabled {
  opacity: 0.32;
  cursor: not-allowed;
}

/* ── Responsive — larger screens ───────────────────────────── */
@media (min-width: 500px) {
  .card-grid {
    gap: 14px;
  }
}

@media (min-width: 700px) {
  .flip-card {
    max-width: 420px;
  }
}

/* ── View fade-in ──────────────────────────────────────────── */
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.view--fade-in {
  animation: fadeIn 0.25s ease;
}

/* ── Reduced motion ─────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  .flip-card__inner { transition-duration: 0.01ms; }
  .card             { transition-duration: 0.01ms; animation: none; }
  .view--fade-in    { animation: none; }
}