/* ═══════════════════════════════════════════════════════════
   水彩调色小游戏 · Premium UI
   Vibe: Soft Structuralism + Editorial Warmth
   Principles: Double-Bezel · Custom Easing · Scroll Reveal
   ═══════════════════════════════════════════════════════════ */

/* ========== CSS Custom Properties ========== */
:root {
  --crust: #FBF8F3;
  --paper: #F4F0E8;
  --surface: #FFFFFF;
  --ink-primary: #2C2824;
  --ink-secondary: #6B6258;
  --ink-tertiary: #9E9588;
  --hairline: rgba(0,0,0,0.06);
  --hairline-strong: rgba(0,0,0,0.10);
  --shadow-ambient: 0 1px 2px rgba(0,0,0,0.03), 0 6px 24px rgba(0,0,0,0.04);
  --shadow-floating: 0 2px 4px rgba(0,0,0,0.02), 0 12px 40px rgba(0,0,0,0.06);
  --radius-sm: 0.75rem;
  --radius-md: 1.25rem;
  --radius-lg: 1.75rem;
  --radius-xl: 2.5rem;
  --ease-premium: cubic-bezier(0.32, 0.72, 0, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 250ms;
  --duration-base: 500ms;
  --duration-slow: 800ms;
  --font-display: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", system-ui, -apple-system, sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", "Cascadia Code", "Consolas", monospace;
}

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

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-display);
  background: var(--crust);
  color: var(--ink-primary);
  min-height: 100dvh;
  overflow-x: hidden;
  line-height: 1.6;
}

/* ── 纸质纹理叠层 (fixed, pointer-events-none) ── */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.025;
  background-image:
    repeating-conic-gradient(#000 0 0.0001%, transparent 0 0.0002%, transparent 0 0.0004%);
}

/* ── 水彩环境光晕 ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(ellipse 80% 60% at 15% 15%, rgba(217, 41, 106, 0.025) 0%, transparent 55%),
    radial-gradient(ellipse 60% 50% at 82% 70%, rgba(46, 111, 191, 0.025) 0%, transparent 55%),
    radial-gradient(ellipse 50% 40% at 45% 90%, rgba(255, 184, 0, 0.02) 0%, transparent 55%);
}

/* ========== App Container ========== */
.app-container {
  max-width: 448px;
  margin: 0 auto;
  padding: 20px 16px 48px;
  position: relative;
  z-index: 1;
}

/* ========== Header ========== */
.header {
  text-align: center;
  padding: 36px 0 20px;
}

.title {
  font-size: 30px;
  font-weight: 200;
  letter-spacing: 0.06em;
  color: var(--ink-primary);
}

.subtitle {
  font-size: 13px;
  color: var(--ink-tertiary);
  margin-top: 6px;
  font-weight: 400;
  letter-spacing: 0.04em;
}

/* ========== Mode Bar — Floating Pill Island ========== */
.mode-bar {
  display: flex;
  gap: 4px;
  padding: 6px;
  background: var(--surface);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-ambient), inset 0 1px 0 rgba(255,255,255,0.8);
  /* Double-bezel: outer ring */
  margin-bottom: 32px;
  position: sticky;
  top: 12px;
  z-index: 100;
}

.mode-btn {
  flex: 1;
  padding: 9px 12px;
  border: none;
  border-radius: calc(var(--radius-xl) - 4px);
  background: transparent;
  color: var(--ink-tertiary);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-premium);
  font-family: var(--font-display);
  letter-spacing: 0.02em;
  position: relative;
}

.mode-btn:hover {
  color: var(--ink-secondary);
}

.mode-btn.active {
  background: var(--ink-primary);
  color: #FFF;
  box-shadow: var(--shadow-ambient);
  font-weight: 600;
}

/* ========== Double-Bezel Section Cards ========== */
.section {
  /* section 本身不再有 margin，由外层壳控制 */
}

/* Outer Shell */
.section-outer {
  margin-bottom: 16px;
  background: rgba(0,0,0,0.02);
  border-radius: var(--radius-lg);
  padding: 1.5px;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.6);
}

/* Inner Core */
.section-inner {
  background: var(--surface);
  border-radius: calc(var(--radius-lg) - 1px);
  padding: 20px 18px;
  box-shadow: var(--shadow-ambient), inset 0 1px 1px rgba(255,255,255,0.8);
}

.section-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
  margin-bottom: 14px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hint-small {
  font-size: 11px;
  color: var(--ink-tertiary);
  font-weight: 400;
  text-transform: none;
}

.hint {
  font-size: 12px;
  color: var(--ink-tertiary);
}

/* ========== Palette Grid ========== */
.palette-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 14px 10px;
  padding: 6px 0 8px;
}

.pigment-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 7px;
  cursor: pointer;
  transition: transform var(--duration-fast) var(--ease-premium);
}

.pigment-wrapper:active {
  transform: scale(0.94);
}

.pigment-dot {
  width: 100%;
  aspect-ratio: 1;
  border-radius: 50%;
  transition: all var(--duration-base) var(--ease-premium);
  box-shadow:
    0 2px 6px rgba(0,0,0,0.06),
    0 0 0 0px var(--surface),
    inset 0 -1px 2px rgba(0,0,0,0.08),
    inset 0 1px 2px rgba(255,255,255,0.3);
}

.pigment-wrapper:hover .pigment-dot {
  transform: scale(1.10);
  box-shadow:
    0 4px 16px rgba(0,0,0,0.10),
    0 0 0 2px var(--surface),
    inset 0 -1px 2px rgba(0,0,0,0.08),
    inset 0 1px 2px rgba(255,255,255,0.3);
}

.pigment-dot.selected {
  transform: scale(1.06);
  box-shadow:
    0 0 0 2.5px var(--ink-primary),
    0 4px 16px rgba(0,0,0,0.14),
    inset 0 -1px 2px rgba(0,0,0,0.10);
}

.pigment-label {
  font-size: 10px;
  color: var(--ink-tertiary);
  text-align: center;
  line-height: 1.2;
  font-weight: 500;
  letter-spacing: 0.02em;
}

@media (max-width: 400px) {
  .palette-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 18px 12px;
  }
}

/* ========== Selected Display ========== */
.selected-display {
  display: flex;
  gap: 6px;
  align-items: center;
  min-height: 32px;
  padding: 6px 0 2px;
  flex-wrap: wrap;
}

.selected-tag {
  padding: 5px 14px;
  border-radius: var(--radius-xl);
  font-size: 12px;
  font-weight: 600;
  color: var(--ink-primary);
  letter-spacing: 0.02em;
}

/* ========== Sliders (Water & Ratio) ========== */
.water-control {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 2px 0;
}

.water-label {
  font-size: 12px;
  color: var(--ink-tertiary);
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* Custom Range Input Styling */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  flex: 1;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(to right, var(--ink-primary), #D4C8B8);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--surface);
  border: 1.5px solid var(--hairline-strong);
  cursor: pointer;
  box-shadow: var(--shadow-floating);
  transition: transform var(--duration-fast) var(--ease-premium),
              box-shadow var(--duration-fast) var(--ease-premium);
}

input[type="range"]::-webkit-slider-thumb:active {
  transform: scale(1.15);
  box-shadow: 0 2px 8px rgba(0,0,0,0.12), 0 0 0 4px rgba(0,0,0,0.04);
}

.water-value {
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-primary);
  min-width: 46px;
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-family: var(--font-mono);
}

/* ========== Action Buttons ========== */
.action-bar {
  display: flex;
  gap: 8px;
  padding: 0 2px 20px;
}

.action-btn {
  padding: 11px 22px;
  border: none;
  border-radius: var(--radius-xl);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-premium);
  font-family: var(--font-display);
  letter-spacing: 0.02em;
  position: relative;
  overflow: hidden;
}

.action-btn:active {
  transform: scale(0.96);
}

.action-btn.primary {
  background: var(--ink-primary);
  color: #FFF;
  flex: 1;
  box-shadow: var(--shadow-ambient);
}

.action-btn.primary:hover {
  background: #3D3832;
  transform: translateY(-1px);
  box-shadow: var(--shadow-floating);
}

.action-btn.secondary {
  background: transparent;
  color: var(--ink-secondary);
  box-shadow: inset 0 0 0 1px var(--hairline-strong);
}

.action-btn.secondary:hover {
  background: rgba(0,0,0,0.02);
  box-shadow: inset 0 0 0 1px rgba(0,0,0,0.16);
}

/* ========== Canvas ========== */
.canvas-preview,
.canvas-swatch {
  width: 100%;
  border-radius: var(--radius-md);
  display: block;
  box-shadow: var(--shadow-ambient), inset 0 1px 0 rgba(255,255,255,0.5);
}

.canvas-preview { height: 120px; }
.canvas-swatch { height: 200px; }

/* ========== Result Info ========== */
.result-info {
  text-align: center;
  padding: 10px 0 6px;
  min-height: 36px;
}

.result-color-name {
  font-size: 24px;
  font-weight: 200;
  color: var(--ink-primary);
  letter-spacing: 0.05em;
  margin-bottom: 2px;
}

.result-hex {
  font-size: 14px;
  color: var(--ink-tertiary);
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}

.result-stats {
  display: flex;
  gap: 20px;
  justify-content: center;
  font-size: 11px;
  color: var(--ink-tertiary);
  letter-spacing: 0.03em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

/* ========== Live Distance (Challenge) ========== */
.live-distance {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--radius-xl);
  margin: 6px 0;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.02em;
}

.live-close {
  background: #EEF7F1;
  color: #2D6A4F;
}

.live-warm {
  background: #FEF8EE;
  color: #B8760E;
}

.live-far {
  background: #F5F2EC;
  color: #8C7A6A;
}

.live-emoji { font-size: 16px; }

.live-grade {
  font-weight: 700;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 8px;
  letter-spacing: 0.04em;
}

.live-close .live-grade { background: #B7E4C7; color: #1B4332; }
.live-warm .live-grade { background: #FFE5A0; color: #7C5800; }
.live-far .live-grade { background: #E8E2D8; color: #5C4E3D; }

/* ========== Result Action Buttons ========== */
.result-actions {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-top: 10px;
}

.save-btn {
  padding: 7px 16px;
  border-radius: var(--radius-xl);
  background: transparent;
  color: var(--ink-tertiary);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-premium);
  font-family: var(--font-display);
  letter-spacing: 0.02em;
  border: none;
  box-shadow: inset 0 0 0 1px var(--hairline);
}

.save-btn:hover {
  color: var(--ink-primary);
  box-shadow: inset 0 0 0 1px var(--hairline-strong);
  background: rgba(0,0,0,0.02);
  transform: translateY(-1px);
}

/* ========== Gallery ========== */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.gallery-item {
  aspect-ratio: 1;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding: 6px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: transform var(--duration-fast) var(--ease-premium),
              box-shadow var(--duration-fast) var(--ease-premium);
  box-shadow: var(--shadow-ambient);
}

.gallery-item:hover {
  transform: scale(1.06);
  box-shadow: var(--shadow-floating);
  z-index: 2;
}

.gallery-name {
  font-size: 10px;
  color: rgba(255,255,255,0.9);
  text-shadow: 0 1px 2px rgba(0,0,0,0.2);
  text-align: center;
  line-height: 1.2;
  font-weight: 500;
}

/* ========== Challenge Header ========== */
.challenge-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 14px;
}

.challenge-info { flex: 1; }

.challenge-target {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  flex-shrink: 0;
  box-shadow:
    0 3px 12px rgba(0,0,0,0.08),
    inset 0 1px 0 rgba(255,255,255,0.4);
}

.challenge-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-primary);
  letter-spacing: 0.02em;
}

.challenge-hint {
  font-size: 12px;
  color: var(--ink-tertiary);
  font-style: italic;
  margin: 2px 0 0;
}

.challenge-actions {
  display: flex;
  gap: 8px;
  margin-bottom: 6px;
}

/* ========== Challenge Feedback ========== */
.challenge-feedback {
  padding: 12px 0 4px;
}

.score-badge {
  display: inline-block;
  width: 52px;
  height: 52px;
  line-height: 52px;
  border-radius: 50%;
  font-size: 26px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 8px;
  letter-spacing: -0.02em;
  box-shadow: var(--shadow-ambient);
}

.grade-S { background: #FFD700; color: #2C2824; }
.grade-A { background: #52B788; color: #FFF; }
.grade-B { background: #74C69D; color: #2C2824; }
.grade-C { background: #FFB800; color: #2C2824; }
.grade-D { background: #F4845F; color: #FFF; }
.grade-F { background: #D8D2C8; color: #FFF; }

.score-label {
  font-size: 15px;
  font-weight: 500;
  color: var(--ink-primary);
  letter-spacing: 0.02em;
}

.score-detail {
  font-size: 12px;
  color: var(--ink-tertiary);
  margin-top: 4px;
}

/* ── Color Compare ── */
.color-compare {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  margin: 10px 0;
}

.compare-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  font-size: 10px;
  color: var(--ink-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.compare-swatch {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  box-shadow: var(--shadow-ambient);
  border: 1.5px solid rgba(255,255,255,0.8);
}

.compare-arrow {
  font-size: 18px;
  color: var(--ink-tertiary);
  margin-top: -10px;
}

/* ── Challenge History ── */
.challenge-history-title {
  text-align: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--ink-tertiary);
  margin: 14px 0 8px;
  padding-top: 12px;
  border-top: 1px solid var(--hairline);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.challenge-history-list {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.history-row {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  background: var(--crust);
  border-radius: var(--radius-sm);
  font-size: 11px;
  color: var(--ink-secondary);
}

.history-grade {
  display: inline-block;
  width: 20px;
  height: 20px;
  line-height: 20px;
  border-radius: 50%;
  text-align: center;
  font-size: 10px;
  font-weight: 700;
  flex-shrink: 0;
}

.history-score {
  margin-left: auto;
  font-weight: 600;
  color: var(--ink-primary);
  font-family: var(--font-mono);
}

/* ========== Learn Mode ========== */
.learn-hint {
  font-size: 14px;
  color: var(--ink-secondary);
  margin-bottom: 14px;
  line-height: 1.6;
  font-weight: 400;
}

.learn-feedback {
  padding: 10px 0 4px;
  font-size: 14px;
  text-align: center;
}

.success { color: #40916C; font-weight: 600; }
.retry { color: #E09B3A; font-weight: 500; }

.learn-complete {
  text-align: center;
  font-size: 18px;
  font-weight: 200;
  color: var(--ink-primary);
  padding: 20px 0;
  letter-spacing: 0.04em;
}

/* ========== Scroll Reveal Animation ========== */
.reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity var(--duration-slow) var(--ease-premium),
              transform var(--duration-slow) var(--ease-premium);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger delays for cascade effect */
.reveal-delay-1 { transition-delay: 0ms; }
.reveal-delay-2 { transition-delay: 80ms; }
.reveal-delay-3 { transition-delay: 160ms; }
.reveal-delay-4 { transition-delay: 240ms; }
.reveal-delay-5 { transition-delay: 320ms; }

/* ========== Mode Panel Transitions ========== */
.mode-panel {
  transition: opacity var(--duration-fast) var(--ease-premium);
}

/* ========== Responsive ========== */
@media (max-width: 360px) {
  .title { font-size: 26px; }
  .mode-btn { font-size: 12px; padding: 8px 6px; }
  .action-bar { flex-direction: column; }
  .challenge-actions { flex-direction: column; }
}