:root {
  --color-bg: #f5f6fb;
  --color-card: #ffffff;
  --color-text: #0d1240;
  --color-text-secondary: #666b8a;
  --color-primary: #07155c;
  --color-primary-dark: #050d3f;
  --color-primary-text: var(--color-primary);
  --color-accent: #ff9209;
  --color-accent-dark: #e07d00;
  --color-sky: #029cfe;
  --color-border: #e3e5f2;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-card: 0 8px 24px rgba(7, 21, 92, 0.1);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0a0e2e;
    --color-card: #131a4a;
    --color-text: #f1f2fa;
    --color-text-secondary: #a6acd6;
    --color-border: #26305f;
    --shadow-card: 0 8px 24px rgba(0, 0, 0, 0.4);
    --color-primary-text: #ffffff;
  }
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
}

.site-header {
  text-align: center;
  padding: 28px 20px 12px;
}

.site-logo {
  width: 56px;
  height: 56px;
  object-fit: cover;
  border-radius: var(--radius-md);
  margin-bottom: 10px;
  box-shadow: var(--shadow-card);
}

.site-header h1 {
  margin: 0 0 4px;
  font-size: 1.35rem;
  line-height: 1.25;
  color: var(--color-primary-text);
}

.site-header p {
  margin: 8px auto 0;
  max-width: 380px;
  color: var(--color-text-secondary);
  font-size: 0.95rem;
}

.app {
  max-width: 520px;
  margin: 0 auto;
  padding: 12px 16px 40px;
}

.state-panel {
  text-align: center;
  padding: 60px 16px;
  color: var(--color-text-secondary);
}

.spinner {
  width: 32px;
  height: 32px;
  margin: 0 auto 16px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.preview-wrap {
  position: relative;
  background: var(--color-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 12px;
}

#preview-canvas {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  touch-action: none;
  cursor: grab;
}

#preview-canvas:active {
  cursor: grabbing;
}

.upload-overlay {
  position: absolute;
  inset: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border-radius: var(--radius-md);
  background: rgba(7, 21, 92, 0.6);
  color: #fff;
  cursor: pointer;
  text-align: center;
  transition: background 0.15s ease;
}

.upload-overlay:hover,
.upload-overlay.drag-over {
  background: rgba(7, 21, 92, 0.75);
}

.upload-title {
  font-weight: 600;
  color: #fff;
}

.upload-hint {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.8);
}

.controls {
  margin-top: 20px;
  background: var(--color-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.control-row {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

.control-row span {
  min-width: 52px;
}

.control-row input[type="range"] {
  flex: 1;
  accent-color: var(--color-accent);
}

.control-buttons {
  display: flex;
  gap: 10px;
}

.btn {
  border: none;
  border-radius: 999px;
  padding: 12px 18px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.1s ease, opacity 0.15s ease, background 0.15s ease;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  width: 100%;
  padding: 15px 18px;
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-secondary {
  background: var(--color-primary);
  color: #fff;
}

.btn-ghost {
  flex: 1;
  background: transparent;
  color: var(--color-primary-text);
  border: 1.5px solid var(--color-border);
}

.btn-link {
  background: none;
  border: none;
  color: var(--color-accent-dark);
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  padding: 4px;
}

.template-tabs {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 4px 2px 16px;
  -webkit-overflow-scrolling: touch;
}

.tab-btn {
  flex: 0 0 auto;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 10px 16px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-card);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
  text-align: left;
}

.tab-btn.is-active {
  border-color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 12%, var(--color-card));
}

.tab-program {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
}

.tab-btn.is-active .tab-program {
  color: var(--color-primary-text);
}

.tab-variant {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
}

.generate-group {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.generate-group .btn-primary {
  width: 100%;
}

.generate-status {
  min-height: 1.2em;
  text-align: center;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

.site-footer {
  text-align: center;
  padding: 20px;
  font-size: 0.78rem;
  color: var(--color-text-secondary);
}