/* ============================================================
   成语连线 — Chinese Idiom Puzzle
   Style: 中国风 (rice-paper, ink, gold accents)
   ============================================================ */

:root {
  /* Palette */
  --color-bg: #F5EDE0;
  --color-bg-soft: #EFE5D3;
  --color-paper: #FAF4E8;
  --color-cell-bg: #FFFFFF;
  --color-cell-border: #D9CFBE;
  --color-ink: #2C2C2C;
  --color-ink-soft: #5A5045;
  --color-muted: #8A7E6E;

  --color-gold: #D4A24C;
  --color-gold-soft: #E8C684;
  --color-gold-deep: #A87A30;

  --color-red: #C25450;
  --color-green: #7DA87D;
  --color-green-soft: #E8F0E0;

  --color-found-bg: #E8E4DC;

  /* Typography */
  --font-serif: "Noto Serif SC", "Songti SC", "STSong", "SimSun", "FangSong", serif;

  /* Spacing & sizing */
  --cell-size: 64px;
  --cell-gap: 8px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Shadows */
  --shadow-soft: 0 2px 8px rgba(60, 40, 10, 0.08);
  --shadow-card: 0 6px 20px rgba(60, 40, 10, 0.12);

  /* Transitions */
  --t-fast: 120ms ease;
  --t-base: 200ms ease;
}

/* -------------------- Reset / base -------------------- */

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

html,
body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  font-family: var(--font-serif);
  color: var(--color-ink);
  background-color: var(--color-bg);
  background-image:
    radial-gradient(ellipse at top, rgba(255, 255, 255, 0.5), transparent 60%),
    repeating-linear-gradient(
      45deg,
      rgba(160, 130, 80, 0.025) 0px,
      rgba(160, 130, 80, 0.025) 2px,
      transparent 2px,
      transparent 6px
    ),
    repeating-linear-gradient(
      -45deg,
      rgba(160, 130, 80, 0.02) 0px,
      rgba(160, 130, 80, 0.02) 2px,
      transparent 2px,
      transparent 7px
    );
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

button {
  font-family: inherit;
  cursor: pointer;
}

h1,
h3 {
  margin: 0;
  font-weight: 600;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

/* -------------------- Header -------------------- */

#header {
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 24px 16px;
  text-align: center;
}

#header h1 {
  font-size: 36px;
  letter-spacing: 6px;
  color: var(--color-ink);
  position: relative;
  display: inline-block;
  padding: 0 24px 6px;
}

#header h1::after {
  content: "";
  display: block;
  width: 60%;
  height: 2px;
  margin: 8px auto 0;
  background: linear-gradient(
    90deg,
    transparent,
    var(--color-gold) 30%,
    var(--color-gold) 70%,
    transparent
  );
}

#counter {
  margin-top: 14px;
  font-size: 16px;
  color: var(--color-ink-soft);
  letter-spacing: 1px;
}

#counter #found-count,
#counter #total-count {
  color: var(--color-gold-deep);
  font-weight: 600;
  font-size: 18px;
  margin: 0 2px;
}

#level-buttons {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.level-btn {
  appearance: none;
  border: 1px solid var(--color-cell-border);
  background: var(--color-paper);
  color: var(--color-ink-soft);
  padding: 8px 16px;
  font-size: 14px;
  letter-spacing: 1px;
  border-radius: var(--radius-md);
  transition: background var(--t-base), color var(--t-base),
    border-color var(--t-base), transform var(--t-fast),
    box-shadow var(--t-base);
}

.level-btn.active {
  background: var(--color-gold);
  color: #FFFFFF;
  border-color: var(--color-gold-deep);
  box-shadow: var(--shadow-soft);
}

@media (hover: hover) {
  .level-btn:hover {
    border-color: var(--color-gold);
    color: var(--color-gold-deep);
  }

  .level-btn.active:hover {
    color: #FFFFFF;
    border-color: var(--color-gold-deep);
  }
}

.level-btn:active {
  transform: translateY(1px);
}

/* -------------------- Board layout -------------------- */

#board-wrapper {
  max-width: 960px;
  margin: 0 auto;
  padding: 16px 24px 48px;
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  justify-content: center;
  gap: 28px;
}

#board {
  position: relative;
  background: var(--color-paper);
  padding: 16px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--color-cell-border);
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

/* -------------------- Grid -------------------- */

#grid {
  display: grid;
  grid-template-columns: repeat(var(--cols, 6), var(--cell-size));
  grid-template-rows: repeat(var(--rows, 6), var(--cell-size));
  gap: var(--cell-gap);
  user-select: none;
  -webkit-user-select: none;
}

/* -------------------- Cell -------------------- */

.cell {
  position: relative;
  width: var(--cell-size);
  height: var(--cell-size);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-cell-bg);
  border: 1px solid var(--color-cell-border);
  border-radius: var(--radius-md);
  font-family: var(--font-serif);
  font-size: 34px;
  font-weight: 500;
  color: var(--color-ink);
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  transition:
    transform var(--t-fast),
    background-color var(--t-base),
    border-color var(--t-base),
    box-shadow var(--t-base),
    opacity var(--t-base);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.6);
}

@media (hover: hover) {
  .cell:hover {
    border-color: var(--color-gold-soft);
  }
}

.cell.selected {
  border: 3px solid var(--color-gold);
  transform: scale(1.06);
  box-shadow:
    0 4px 12px rgba(212, 162, 76, 0.35),
    inset 0 0 0 1px rgba(255, 255, 255, 0.7);
  z-index: 2;
}

.cell.partial-found {
  background-color: var(--color-green-soft);
  border-color: #BBD0A8;
}

.cell.fully-found {
  opacity: 0.5;
  background-color: var(--color-found-bg);
  font-style: italic;
  color: var(--color-muted);
  cursor: default;
}

/* -------------------- Cell badge -------------------- */

.cell-badge {
  position: absolute;
  top: 3px;
  right: 4px;
  font-family: var(--font-serif);
  font-size: 10px;
  line-height: 1;
  padding: 2px 4px;
  color: var(--color-gold-deep);
  background: rgba(255, 248, 230, 0.85);
  border: 1px solid var(--color-gold-soft);
  border-radius: 4px;
  font-style: normal;
  font-weight: 600;
  letter-spacing: 0;
  pointer-events: none;
}

/* -------------------- Connection layer -------------------- */

#connection-layer {
  position: absolute;
  top: 16px;
  left: 16px;
  width: calc(100% - 32px);
  height: calc(100% - 32px);
  pointer-events: none;
  overflow: visible;
}

.connection-line {
  fill: none;
  stroke: var(--color-gold);
  stroke-width: 6;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: 0.85;
  transition: stroke var(--t-fast), opacity var(--t-base);
}

.connection-line.invalid {
  stroke: var(--color-red);
}

.connection-line.success {
  stroke: var(--color-green);
}

.connection-line.persistent {
  stroke: var(--color-gold);
  opacity: 0.35;
}

/* -------------------- Found panel -------------------- */

#found-panel {
  width: 240px;
  flex-shrink: 0;
  background: var(--color-paper);
  border: 1px solid var(--color-cell-border);
  border-radius: var(--radius-lg);
  padding: 18px 18px 22px;
  box-shadow: var(--shadow-card);
  max-height: 520px;
  display: flex;
  flex-direction: column;
}

#found-panel h3 {
  font-size: 18px;
  letter-spacing: 3px;
  color: var(--color-ink);
  text-align: center;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--color-gold-soft);
  position: relative;
}

#found-panel h3::before,
#found-panel h3::after {
  content: "❖";
  color: var(--color-gold);
  font-size: 12px;
  margin: 0 6px;
  vertical-align: middle;
}

#found-list {
  overflow-y: auto;
  flex: 1;
  padding-right: 4px;
}

#found-list::-webkit-scrollbar {
  width: 6px;
}

#found-list::-webkit-scrollbar-thumb {
  background: var(--color-gold-soft);
  border-radius: 3px;
}

.found-item {
  padding: 10px 12px;
  margin-bottom: 8px;
  background: linear-gradient(
    180deg,
    var(--color-paper) 0%,
    var(--color-bg-soft) 100%
  );
  border: 1px solid var(--color-cell-border);
  border-left: 3px solid var(--color-gold);
  border-radius: var(--radius-sm);
  font-family: var(--font-serif);
  position: relative;
  animation: foundFadeIn 320ms ease;
}

.found-item::before {
  content: "✓ ";
  color: var(--color-green);
  font-weight: 700;
  margin-right: 4px;
}

.found-item .idiom,
.found-item strong {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--color-ink);
}

.found-item .meaning,
.found-item small,
.found-item em {
  display: block;
  margin-top: 4px;
  margin-left: 18px;
  font-size: 12px;
  font-style: normal;
  color: var(--color-muted);
  line-height: 1.5;
  letter-spacing: 0.5px;
}

@keyframes foundFadeIn {
  from {
    opacity: 0;
    transform: translateX(8px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* -------------------- Toast -------------------- */

.toast {
  position: fixed;
  top: 24px;
  left: 50%;
  transform: translate(-50%, -120%);
  background: #FFFFFF;
  color: var(--color-ink);
  padding: 14px 28px;
  font-family: var(--font-serif);
  font-size: 16px;
  letter-spacing: 2px;
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-green);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
  opacity: 0;
  pointer-events: none;
  transition: transform 320ms cubic-bezier(0.2, 0.8, 0.2, 1),
    opacity 280ms ease;
  z-index: 1000;
}

#toast.show {
  transform: translate(-50%, 0);
  opacity: 1;
}

/* -------------------- Shake animation -------------------- */

.shake {
  animation: shake 0.4s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
}

@keyframes shake {
  10%, 90% { transform: translateX(-2px); }
  20%, 80% { transform: translateX(3px); }
  30%, 50%, 70% { transform: translateX(-5px); }
  40%, 60% { transform: translateX(5px); }
}

/* Keep selected scale even during shake by scoping shake to a different
   transform path: in practice JS will toggle .shake briefly on cells. */
.cell.selected.shake {
  animation: shakeSelected 0.4s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
}

@keyframes shakeSelected {
  10%, 90% { transform: scale(1.06) translateX(-2px); }
  20%, 80% { transform: scale(1.06) translateX(3px); }
  30%, 50%, 70% { transform: scale(1.06) translateX(-5px); }
  40%, 60% { transform: scale(1.06) translateX(5px); }
}

/* -------------------- Responsive -------------------- */

@media (max-width: 880px) {
  :root {
    --cell-size: 56px;
    --cell-gap: 6px;
  }

  #board-wrapper {
    flex-direction: column;
    align-items: center;
    gap: 20px;
  }

  #found-panel {
    width: 100%;
    max-width: 480px;
    max-height: 280px;
  }

  #header h1 {
    font-size: 30px;
    letter-spacing: 4px;
  }

  .cell {
    font-size: 28px;
  }
}

@media (max-width: 480px) {
  :root {
    --cell-size: 46px;
    --cell-gap: 5px;
  }

  #header {
    padding: 20px 12px 12px;
  }

  #board-wrapper {
    padding: 12px 12px 32px;
  }

  #header h1 {
    font-size: 26px;
    letter-spacing: 3px;
  }

  .cell {
    font-size: 22px;
  }

  .level-btn {
    font-size: 12px;
    padding: 6px 10px;
  }
}