/* ===== Design Tokens ===== */
:root {
  --color-bg: #0d0d14;
  --color-surface: #161622;
  --color-surface-hover: #1e1e30;
  --color-border: #2a2a44;
  --color-text: #e4e4ec;
  --color-text-muted: #8888a4;
  --color-accent: #d4a745;
  --color-accent-soft: rgba(212, 167, 69, 0.12);
  --color-accent-glow: rgba(212, 167, 69, 0.25);
  --color-danger: #e0556a;
  --color-success: #5cb878;

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 5rem;

  --font-sans: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.25rem;
  --text-xl: 1.5rem;
  --text-2xl: 2rem;
  --text-3xl: 2.5rem;
  --text-4xl: 3.5rem;

  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;

  --shadow-card: 0 2px 16px rgba(0, 0, 0, 0.25);
  --shadow-elevated: 0 8px 32px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 40px var(--color-accent-glow);

  --nav-height: 3.5rem;
  --content-max-width: 72rem;
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
}

img { max-width: 100%; display: block; }
a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }
button { cursor: pointer; font: inherit; }
ul, ol { list-style: none; }

/* ===== Typography ===== */
h1, h2, h3, h4 {
  line-height: 1.25;
  font-weight: 700;
  letter-spacing: -0.02em;
}
h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }

.text-muted { color: var(--color-text-muted); }
.text-accent { color: var(--color-accent); }
.text-sm { font-size: var(--text-sm); }

/* ===== Navigation ===== */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
  padding: 0 var(--space-xl);
  background: rgba(13, 13, 20, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav-logo {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}
.nav-logo:hover { text-decoration: none; color: var(--color-accent); }

.nav-logo span { color: var(--color-accent); }

.nav-links {
  display: flex;
  gap: var(--space-xs);
}

.nav-links a {
  display: block;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
  background: var(--color-surface-hover);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text);
  font-size: 1.5rem;
  padding: var(--space-sm);
}

@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition-base), opacity var(--transition-base);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-toggle { display: block; }
}

/* ===== Layout ===== */
.container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section {
  padding: var(--space-3xl) 0;
}

.section-header {
  text-align: center;
  max-width: 40rem;
  margin: 0 auto var(--space-3xl);
}

.section-header h2 { margin-bottom: var(--space-md); }
.section-header p { color: var(--color-text-muted); font-size: var(--text-lg); }

/* ===== Card Grid ===== */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
}

@media (min-width: 640px) {
  .card-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .card-grid { grid-template-columns: repeat(3, 1fr); }
}

.card-grid.cols-2 {
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .card-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
}

/* ===== Card ===== */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-elevated);
  border-color: var(--color-accent);
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-md);
  display: block;
}

.card h3 {
  margin-bottom: var(--space-sm);
}

.card h3 a {
  color: var(--color-text);
}

.card h3 a:hover {
  color: var(--color-accent);
  text-decoration: none;
}

.card .trigger {
  display: block;
  color: var(--color-accent);
  font-size: var(--text-sm);
  font-weight: 600;
  padding-left: var(--space-md);
  border-left: 2px solid var(--color-accent);
  margin: var(--space-md) 0;
}

.card .steps {
  margin: var(--space-md) 0;
}

.card .steps li {
  padding: var(--space-xs) 0;
  padding-left: var(--space-lg);
  position: relative;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: 1.6;
}

.card .steps li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.65em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
}

.card .avoid {
  margin-top: var(--space-md);
  padding: var(--space-md);
  background: rgba(224, 85, 106, 0.08);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-danger);
}

.card .avoid strong {
  display: block;
  margin-bottom: var(--space-xs);
}

/* ===== Hero ===== */
.hero {
  padding: var(--space-3xl) 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero h1 {
  max-width: 20ch;
  margin: 0 auto var(--space-lg);
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .subtitle {
  font-size: var(--text-xl);
  color: var(--color-text-muted);
  max-width: 30ch;
  margin: 0 auto var(--space-2xl);
}

/* Bokeh background */
.hero::before,
.hero::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  opacity: 0.08;
  pointer-events: none;
}

.hero::before {
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, var(--color-accent), transparent);
  top: -100px;
  right: -100px;
  animation: float 8s ease-in-out infinite;
}

.hero::after {
  width: 200px;
  height: 200px;
  background: radial-gradient(circle, var(--color-accent), transparent);
  bottom: -50px;
  left: -50px;
  animation: float 6s ease-in-out infinite reverse;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(20px, -30px) scale(1.1); }
  66% { transform: translate(-10px, 20px) scale(0.95); }
}

/* ===== Quick Entry Grid (Home) ===== */
.quick-entry {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--space-md);
}

.quick-entry .entry-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xl) var(--space-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
  text-decoration: none;
  color: var(--color-text);
}

.quick-entry .entry-card:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-glow);
  transform: translateY(-4px);
  text-decoration: none;
}

.quick-entry .entry-icon {
  font-size: 2.5rem;
}

.quick-entry .entry-label {
  font-weight: 600;
  font-size: var(--text-sm);
}

/* ===== Technique Page Layout ===== */
.technique-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xl);
}

.technique-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.technique-card .tc-header {
  padding: var(--space-xl);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: flex-start;
  gap: var(--space-lg);
}

.technique-card .tc-number {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-accent);
  opacity: 0.3;
  line-height: 1;
  flex-shrink: 0;
}

.technique-card .tc-body {
  padding: var(--space-xl);
  display: grid;
  gap: var(--space-lg);
}

@media (min-width: 768px) {
  .technique-card .tc-body {
    grid-template-columns: 1fr 1fr;
  }
}

.technique-card .tc-diagram {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  overflow: hidden;
}

/* ===== Before/After Slider ===== */
.ba-slider {
  position: relative;
  width: 100%;
  aspect-ratio: 3/2;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-bg);
  user-select: none;
  -webkit-user-select: none;
}

.ba-slider .ba-before,
.ba-slider .ba-after {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
  font-weight: 600;
}

.ba-slider .ba-before {
  background: var(--color-surface);
  z-index: 2;
}

.ba-slider .ba-after {
  background: var(--color-surface);
  z-index: 1;
}

.ba-slider .ba-handle {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--color-accent);
  z-index: 3;
  cursor: ew-resize;
  pointer-events: auto;
  touch-action: none;
}

.ba-slider .ba-handle::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 3px solid var(--color-bg);
  box-shadow: 0 0 12px rgba(0,0,0,0.5);
}

.ba-slider .ba-label {
  position: absolute;
  bottom: var(--space-md);
  padding: var(--space-xs) var(--space-md);
  background: rgba(0,0,0,0.7);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  z-index: 4;
  pointer-events: none;
}

.ba-slider .ba-label.bad {
  right: var(--space-md);
  color: var(--color-danger);
}

.ba-slider .ba-label.good {
  left: var(--space-md);
  color: var(--color-success);
}

/* ===== Decision Tree / Wizard ===== */
.wizard {
  max-width: 36rem;
  margin: 0 auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.wizard .wizard-step {
  padding: var(--space-2xl);
  animation: fadeSlideIn 0.3s ease;
}

@keyframes fadeSlideIn {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}

.wizard .wizard-question {
  font-size: var(--text-xl);
  font-weight: 700;
  margin-bottom: var(--space-xl);
  text-align: center;
}

.wizard .wizard-options {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.wizard .wizard-btn {
  display: block;
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  background: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font-size: var(--text-base);
  font-weight: 500;
  text-align: left;
  transition: all var(--transition-fast);
}

.wizard .wizard-btn:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-soft);
}

.wizard .wizard-result {
  padding: var(--space-2xl);
}

.wizard .wizard-result h3 {
  color: var(--color-accent);
  margin-bottom: var(--space-lg);
}

.wizard .wizard-result .result-steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.wizard .wizard-result .result-step {
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
}

.wizard .wizard-result .step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--text-sm);
  flex-shrink: 0;
}

.wizard .wizard-back {
  display: block;
  margin: var(--space-md) auto 0;
  padding: var(--space-sm) var(--space-lg);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  transition: all var(--transition-fast);
}

.wizard .wizard-back:hover {
  border-color: var(--color-text-muted);
  color: var(--color-text);
}

.wizard .wizard-restart {
  display: block;
  margin: var(--space-lg) auto 0;
  padding: var(--space-md) var(--space-xl);
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-md);
  color: var(--color-bg);
  font-weight: 600;
  font-size: var(--text-sm);
}

/* ===== Checklist ===== */
.checklist {
  max-width: 36rem;
  margin: 0 auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
}

.checklist .checklist-scene-select {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.checklist .scene-chip {
  padding: var(--space-sm) var(--space-lg);
  border-radius: 100px;
  border: 1px solid var(--color-border);
  background: none;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.checklist .scene-chip:hover {
  border-color: var(--color-accent);
  color: var(--color-text);
}

.checklist .scene-chip.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-bg);
}

.checklist .checklist-progress {
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  margin-bottom: var(--space-xl);
  overflow: hidden;
}

.checklist .checklist-progress-bar {
  height: 100%;
  background: var(--color-accent);
  border-radius: 2px;
  transition: width var(--transition-base);
}

.checklist .checklist-items {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.checklist .checklist-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.checklist .checklist-item:hover {
  background: var(--color-surface-hover);
}

.checklist .checklist-check {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid var(--color-border);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.checklist .checklist-item.done .checklist-check {
  background: var(--color-success);
  border-color: var(--color-success);
}

.checklist .checklist-check::after {
  content: '';
  display: block;
  width: 6px;
  height: 10px;
  border: solid var(--color-bg);
  border-width: 0 2px 2px 0;
  transform: rotate(45deg) translateY(-1px);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.checklist .checklist-item.done .checklist-check::after {
  opacity: 1;
}

.checklist .checklist-item.done .checklist-label {
  text-decoration: line-through;
  color: var(--color-text-muted);
}

.checklist .checklist-actions {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-xl);
}

/* ===== Grid Overlay Tool ===== */
.grid-tool {
  max-width: 48rem;
  margin: 0 auto;
}

.grid-tool .grid-canvas-container {
  position: relative;
  width: 100%;
  aspect-ratio: 4/3;
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.grid-tool .grid-canvas-container canvas {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.grid-tool .grid-placeholder {
  text-align: center;
  color: var(--color-text-muted);
  padding: var(--space-2xl);
}

.grid-tool .grid-placeholder .grid-placeholder-icon {
  font-size: 3rem;
  display: block;
  margin-bottom: var(--space-md);
}

.grid-tool .grid-controls {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  align-items: center;
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
}

.grid-tool .grid-controls label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 500;
}

.grid-tool .grid-type-btns {
  display: flex;
  gap: var(--space-xs);
}

.grid-tool .grid-type-btn {
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: none;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.grid-tool .grid-type-btn:hover {
  border-color: var(--color-accent);
}

.grid-tool .grid-type-btn.active {
  background: var(--color-accent-soft);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.grid-tool .opacity-slider {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.grid-tool input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  outline: none;
}

.grid-tool input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-accent);
  cursor: pointer;
}

.grid-tool .grid-upload-btn {
  padding: var(--space-sm) var(--space-lg);
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-sm);
  color: var(--color-bg);
  font-weight: 600;
  font-size: var(--text-sm);
  transition: opacity var(--transition-fast);
}

.grid-tool .grid-upload-btn:hover { opacity: 0.9; }

/* ===== Before/After Slider Content ===== */
.ba-content {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  flex-direction: column;
  text-align: center;
  padding: var(--space-lg);
}

.ba-content .ba-icon { font-size: 3rem; margin-bottom: var(--space-md); }
.ba-content .ba-desc { font-size: var(--text-sm); color: var(--color-text-muted); max-width: 20ch; }

.ba-after .ba-content .ba-icon { color: var(--color-success); }
.ba-before .ba-content .ba-icon { color: var(--color-danger); }

/* ===== Mistake Card ===== */
.mistake-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xl);
}

.mistake-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.mistake-card .mc-header {
  padding: var(--space-xl);
  border-bottom: 1px solid var(--color-border);
}

.mistake-card .mc-header h3 {
  color: var(--color-danger);
  margin-bottom: var(--space-xs);
}

.mistake-card .mc-header .mc-scenario {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.mistake-card .mc-body {
  padding: var(--space-xl);
  display: grid;
  gap: var(--space-xl);
}

@media (min-width: 768px) {
  .mistake-card .mc-body {
    grid-template-columns: 2fr 1fr;
  }
}

.mistake-card .mc-fix h4 {
  color: var(--color-success);
  margin-bottom: var(--space-sm);
}

.mistake-card .mc-fix p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: 1.7;
}

.mistake-card .mc-mnemonic {
  padding: var(--space-lg);
  background: var(--color-accent-soft);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-accent);
}

.mistake-card .mc-mnemonic h4 {
  color: var(--color-accent);
  margin-bottom: var(--space-xs);
  font-size: var(--text-base);
}

.mistake-card .mc-mnemonic p {
  color: var(--color-text);
  font-weight: 600;
}

/* ===== Scene Page ===== */
.scene-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-2xl);
  position: sticky;
  top: calc(var(--nav-height) + var(--space-md));
  z-index: 10;
  padding: var(--space-sm);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.scene-nav a {
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  transition: all var(--transition-fast);
}

.scene-nav a:hover {
  background: var(--color-surface-hover);
  color: var(--color-text);
  text-decoration: none;
}

.scene-section {
  padding: var(--space-2xl) 0;
  border-bottom: 1px solid var(--color-border);
}

.scene-section:last-child { border-bottom: none; }

.scene-section .scene-hero {
  display: grid;
  gap: var(--space-2xl);
  align-items: center;
}

@media (min-width: 768px) {
  .scene-section .scene-hero {
    grid-template-columns: 1fr 1fr;
  }
}

.scene-section .scene-diagram {
  aspect-ratio: 1;
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: var(--text-base);
  text-align: center;
  transition: all var(--transition-fast);
  border: none;
}

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

.btn-primary:hover {
  box-shadow: var(--shadow-glow);
  text-decoration: none;
}

.btn-outline {
  background: none;
  border: 1px solid var(--color-border);
  color: var(--color-text);
}

.btn-outline:hover {
  border-color: var(--color-accent);
  text-decoration: none;
}

.btn-lg {
  padding: var(--space-lg) var(--space-2xl);
  font-size: var(--text-lg);
}

.btn-sm {
  padding: var(--space-sm) var(--space-md);
  font-size: var(--text-sm);
}

/* ===== Footer ===== */
.site-footer {
  text-align: center;
  padding: var(--space-2xl);
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* ===== Light Direction Diagram ===== */
.light-diagram {
  position: relative;
  width: 280px;
  height: 280px;
  margin: 0 auto;
  border-radius: 50%;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
}

.light-diagram .center-subject {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 2.5rem;
}

.light-diagram .sun {
  position: absolute;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-accent);
  cursor: grab;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: 0 0 20px var(--color-accent-glow);
  transform: translate(-50%, -50%);
  transition: box-shadow var(--transition-fast);
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

.light-diagram .sun:active {
  cursor: grabbing;
  box-shadow: 0 0 32px var(--color-accent-glow);
}

.light-diagram .light-label {
  text-align: center;
  margin-top: var(--space-lg);
  font-weight: 600;
  font-size: var(--text-lg);
}
.light-diagram .light-desc {
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  margin-top: var(--space-xs);
}

/* ===== Utility ===== */
.text-center { text-align: center; }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mt-2xl { margin-top: var(--space-2xl); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

/* ===== Print Styles ===== */
@media print {
  .site-nav,
  .site-footer,
  .nav-toggle,
  .grid-controls,
  .checklist-actions button:not(.print-only),
  .wizard-restart,
  .wizard-back { display: none !important; }

  body {
    background: white;
    color: black;
    font-size: 12pt;
  }

  .card, .technique-card, .mistake-card {
    break-inside: avoid;
    border: 1px solid #ccc;
    background: white;
  }

  .checklist .checklist-check {
    border-color: #999;
  }

  .checklist .checklist-item.done .checklist-check {
    background: black;
    border-color: black;
  }
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }

  html { scroll-behavior: auto; }
}

/* ===== Camera Mode ===== */
.grid-camera-btn {
  padding: var(--space-sm) var(--space-lg);
  background: var(--color-surface-hover);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-sm);
  color: var(--color-accent);
  font-weight: 600;
  font-size: var(--text-sm);
  transition: all var(--transition-fast);
}

.grid-camera-btn:hover { background: var(--color-accent-soft); }

.grid-camera-btn.active {
  background: var(--color-accent);
  color: var(--color-bg);
}

.grid-flip-btn {
  padding: var(--space-sm) var(--space-md);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: var(--text-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.grid-flip-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ===== Capture Button ===== */
.grid-capture-btn {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: rgba(255,255,255,0.9);
  border: 4px solid var(--color-bg);
  color: var(--color-bg);
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 10;
  transition: all var(--transition-fast);
  box-shadow: 0 4px 20px rgba(0,0,0,0.4);
}

.grid-capture-btn:hover {
  background: #fff;
  transform: translateX(-50%) scale(1.08);
}

.grid-capture-btn:active {
  transform: translateX(-50%) scale(0.94);
  transition: transform 0.05s ease;
}

/* ===== Filter Buttons ===== */
.grid-control-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 500;
  white-space: nowrap;
}

.grid-filter-group {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.grid-filter-btns {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.grid-filter-btn {
  padding: 4px 10px;
  border: 1px solid var(--color-border);
  border-radius: 100px;
  background: none;
  color: var(--color-text-muted);
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.grid-filter-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.grid-filter-btn.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-bg);
}

/* ===== Lazy Mode ===== */
.lazy-section {
  text-align: center;
  padding: var(--space-2xl) 0;
}

.lazy-btn {
  display: inline-block;
  padding: var(--space-lg) var(--space-3xl);
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-xl);
  color: var(--color-bg);
  font-weight: 700;
  font-size: var(--text-xl);
  cursor: pointer;
  transition: all var(--transition-base);
  box-shadow: 0 0 0 0 var(--color-accent-glow);
}

.lazy-btn:hover {
  box-shadow: 0 0 40px var(--color-accent-glow);
  transform: scale(1.03);
}

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

.lazy-advice-card {
  max-width: 42rem;
  margin: var(--space-2xl) auto 0;
  background: var(--color-surface);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  text-align: left;
  animation: fadeSlideIn 0.4s ease;
}

.lazy-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.lazy-icon { font-size: 2.5rem; }

.lazy-header h3 {
  color: var(--color-accent);
  font-size: var(--text-xl);
}

.lazy-steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  counter-reset: lazy;
}

.lazy-steps li {
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
  font-size: var(--text-base);
  line-height: 1.7;
}

.lazy-steps li::before {
  counter-increment: lazy;
  content: counter(lazy);
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--text-sm);
  flex-shrink: 0;
}

.lazy-footer {
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* ===== Checklist Export Button ===== */
.checklist-export {
  padding: var(--space-sm) var(--space-lg);
  background: var(--color-accent-soft);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-sm);
  color: var(--color-accent);
  font-weight: 600;
  font-size: var(--text-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.checklist-export:hover {
  background: var(--color-accent);
  color: var(--color-bg);
}

/* ===== Instant Answer Card (Home) ===== */
.instant-card {
  max-width: 36rem;
  margin: 0 auto;
  padding: var(--space-2xl);
  background: var(--color-surface);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-xl);
  text-align: center;
  animation: fadeSlideIn 0.4s ease;
}

.instant-card h3 {
  color: var(--color-accent);
  margin-bottom: var(--space-md);
}

.instant-card .instant-scene {
  display: inline-block;
  padding: var(--space-xs) var(--space-md);
  background: var(--color-accent-soft);
  border-radius: 100px;
  color: var(--color-accent);
  font-size: var(--text-sm);
  font-weight: 600;
  margin-bottom: var(--space-lg);
}

.instant-card .instant-steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  text-align: left;
  margin-bottom: var(--space-lg);
}

.instant-card .instant-step {
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
  padding: var(--space-md);
  background: var(--color-bg);
  border-radius: var(--radius-md);
}

.instant-card .instant-step .step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--text-sm);
  flex-shrink: 0;
}

.instant-card .instant-step p {
  font-size: var(--text-sm);
  line-height: 1.6;
}

.instant-card .instant-again {
  margin-top: var(--space-md);
  padding: var(--space-sm) var(--space-xl);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.instant-card .instant-again:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ===== SVG Scene Diagram Animations ===== */
.ba-svg {
  width: 100%;
  height: 100%;
}

.ba-svg .mistake-element {
  opacity: 0.7;
}

.ba-svg .correct-element {
  opacity: 1;
}