/* Catppuccin Mocha palette */
:root {
  --ctp-base: #1e1e2e;
  --ctp-mantle: #181825;
  --ctp-crust: #11111b;
  --ctp-surface0: #313244;
  --ctp-surface1: #45475a;
  --ctp-subtext0: #a6adc8;
  --ctp-text: #cdd6f4;
  --ctp-lavender: #b4befe;
  --ctp-blue: #89b4fa;
  --ctp-mauve: #cba6f7;
  --ctp-green: #a6e3a1;
  --ctp-red: #f38ba8;
  --ctp-peach: #fab387;
  --ctp-yellow: #f9e2af;
  --ctp-flint: #9399b2;
  --ctp-rosewater: #f5c2e7;
}

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

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background-color: var(--ctp-base);
  color: var(--ctp-text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0;
}

.container {
  max-width: 32.5rem;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  margin: auto 0;
  padding: 2rem 1rem;
}

/* Header */
header {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
}

.top-nav {
  width: 100%;
  background-color: var(--ctp-mantle);
  padding: 0.75rem 1rem;
  display: flex;
  justify-content: center;
  border-bottom: 0.0625rem solid var(--ctp-surface1);
}

.back-link {
  color: var(--ctp-blue);
  text-decoration: none;
  font-size: 0.875rem;
  transition: color 0.15s ease;
}

.back-link:hover {
  color: var(--ctp-lavender);
}

h1 {
  color: var(--ctp-mauve);
  font-size: 1.75rem;
  font-weight: 700;
}

.subtitle {
  color: var(--ctp-subtext0);
  font-size: 0.875rem;
}

/* Controls */
.controls {
  display: flex;
  gap: 0.75rem;
  width: 100%;
}

#search-input {
  flex: 1;
  padding: 0.625rem 0.875rem;
  font-size: 0.9375rem;
  background-color: var(--ctp-surface0);
  color: var(--ctp-text);
  border: 0.125rem solid var(--ctp-surface1);
  border-radius: 0.5rem;
  outline: none;
  transition: border-color 0.15s ease;
}

#search-input::placeholder {
  color: var(--ctp-subtext0);
}

#search-input:focus {
  border-color: var(--ctp-blue);
}

#shuffle-btn {
  padding: 0.625rem 1rem;
  font-size: 0.9375rem;
  background-color: var(--ctp-surface0);
  color: var(--ctp-text);
  border: 0.125rem solid var(--ctp-surface1);
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease;
  white-space: nowrap;
}

#shuffle-btn:hover {
  border-color: var(--ctp-blue);
}

/* Progress */
.progress {
  font-size: 0.875rem;
  color: var(--ctp-subtext0);
  font-weight: 600;
  letter-spacing: 0.05em;
}

/* Card scene (3D perspective) */
.card-scene {
  width: 100%;
  height: 17.5rem;
  perspective: 50rem;
  cursor: pointer;
}

.card {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s ease;
}

.card.is-flipped {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: 1rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 2rem;
  background-color: var(--ctp-surface0);
  border: 0.125rem solid var(--ctp-surface1);
}

.card-front {
  transform: rotateY(0deg);
}

.card-back {
  transform: rotateY(180deg);
}

.chinese {
  font-size: 3.5rem;
  color: var(--ctp-text);
  font-weight: 700;
  line-height: 1.2;
  text-align: center;
}

.pinyin {
  font-size: 1.5rem;
  color: var(--ctp-lavender);
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.english {
  font-size: 1.125rem;
  color: var(--ctp-subtext0);
  text-align: center;
}

/* Navigation */
.navigation {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  width: 100%;
  justify-content: space-between;
}

#prev-btn,
#next-btn {
  padding: 0.625rem 1.25rem;
  font-size: 0.9375rem;
  background-color: var(--ctp-surface0);
  color: var(--ctp-text);
  border: 0.125rem solid var(--ctp-surface1);
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}

#prev-btn:hover,
#next-btn:hover {
  border-color: var(--ctp-blue);
}

#prev-btn:disabled,
#next-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.flip-hint {
  font-size: 0.75rem;
  color: var(--ctp-flint);
  text-align: center;
}

/* No results state */
.no-results {
  color: var(--ctp-subtext0);
  text-align: center;
  font-size: 1rem;
  padding: 2rem 0;
}

/* Responsive */
@media (max-width: 37.5rem) {
  .card-scene {
    height: 15rem;
  }

  .chinese {
    font-size: 2.5rem;
  }

  .navigation {
    gap: 1rem;
  }

  #prev-btn,
  #next-btn {
    padding: 0.625rem 0.875rem;
    font-size: 0.8125rem;
  }
}