:root {
  /* GitHub Dark Dimmed Theme - True Colors */
  --bg-canvas: #0d1117;
  --bg-canvas-subtle: #161b22;
  --bg-canvas-inset: #0d1117;

  --border-default: #30363d;
  --border-muted: #21262d;

  --fg-default: #c9d1d9;
  --fg-muted: #8b949e;
  --fg-subtle: #484f58;

  --accent-fg: #58a6ff;
  --accent-emphasis: #1f6feb;
  --accent-muted: rgba(56, 139, 253, 0.4);
  --accent-subtle: rgba(56, 139, 253, 0.15);

  --success-fg: #3fb950;
  --success-emphasis: #238636;
  --success-muted: rgba(46, 160, 67, 0.4);

  --danger-fg: #f85149;
  --danger-emphasis: #da3633;

  --btn-bg: #373e47;
  --btn-hover: #444c56;
  --btn-border: rgba(205, 217, 229, 0.1);
  --btn-primary-bg: #347d39;
  --btn-primary-hover: #46954a;

  --radius: 6px;
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-canvas);
  color: var(--fg-default);
  min-height: 100vh;
  line-height: 1.5;
  font-size: 14px;
}

.container {
  max-width: 1012px;
  /* GitHub standard width */
  margin: 0 auto;
  padding: 40px 24px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 48px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
  color: var(--fg-default);
}

.logo h1 {
  font-size: 24px;
  font-weight: 600;
  color: var(--fg-default);
  letter-spacing: -0.5px;
}

.tagline {
  color: var(--fg-muted);
  font-size: 16px;
}

/* Main Layout */
.main {
  display: grid;
  grid-template-columns: 350px 1fr;
  gap: 32px;
  flex: 1;
  align-items: start;
}

/* Panels (Cards) */
.config-panel,
.preview-panel {
  background-color: var(--bg-canvas);
  /* Clean native look, no separate card bg usually, but for sections we use border */
  border: 1px solid var(--border-default);
  border-radius: var(--radius);
}

/* Config Panel */
.config-panel {
  overflow: hidden;
}

.config-panel>div {
  padding: 13px;
  border-bottom: 1px solid var(--border-muted);
}

.config-panel>div:last-child {
  border-bottom: none;
}

.input-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--fg-default);
  font-size: 14px;
  text-transform: none;
  letter-spacing: normal;
}

.input-row {
  display: flex;
  gap: 8px;
}

.input-row input {
  flex: 1;
  padding: 5px 12px;
  height: 32px;
  background-color: var(--bg-canvas-subtle);
  border: 1px solid var(--border-default);
  border-radius: var(--radius);
  color: var(--fg-default);
  font-size: 14px;
  font-family: inherit;
  box-shadow: none;
  /* Flattened */
}

.input-row input:focus {
  outline: none;
  border-color: var(--accent-fg);
  box-shadow: 0 0 0 3px var(--accent-subtle);
}

.btn-primary {
  padding: 5px 16px;
  height: 32px;
  background-color: var(--btn-primary-bg);
  color: #ffffff;
  border: 1px solid rgba(205, 217, 229, 0.1);
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: 0.2s;
}

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

/* Toggles */
.toggles h3,
.color-picker h3 {
  font-size: 14px;
  font-weight: 600;
  color: var(--fg-default);
  margin-bottom: 16px;
  text-transform: none;
  letter-spacing: normal;
}

.toggle {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
  cursor: pointer;
}

.toggle input {
  display: none;
}

/* GitHub Toggle Switch Style */
.toggle-slider {
  width: 32px;
  height: 16px;
  background: var(--border-muted);
  /* Inactive track */
  border-radius: 100px;
  position: relative;
  transition: background 0.2s;
  flex-shrink: 0;
  border: 2px solid transparent;
  /* Mimic sizing */
}

.toggle-slider::after {
  content: '';
  width: 12px;
  height: 12px;
  background: #ffffff;
  border-radius: 50%;
  position: absolute;
  top: 0px;
  left: 0px;
  transition: transform 0.2s;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
}

.toggle input:checked+.toggle-slider {
  background: var(--success-emphasis);
  border-color: var(--success-emphasis);
}

.toggle input:checked+.toggle-slider::after {
  transform: translateX(16px);
}

.toggle-label {
  font-size: 14px;
  color: var(--fg-default);
}

/* Color Picker */
.color-options {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.color-btn {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: var(--c);
  cursor: pointer;
  transition: transform 0.1s;
}

.color-btn:hover {
  transform: scale(1.1);
}

.color-btn.active {
  box-shadow: 0 0 0 2px var(--bg-canvas), 0 0 0 4px var(--accent-fg);
}

.custom-color {
  display: flex;
  align-items: center;
  gap: 8px;
}

.custom-color input[type="color"] {
  background: transparent;
  width: 28px;
  height: 28px;
  border: none;
  cursor: pointer;
}

/* Preview Panel */
.preview-panel {
  padding: 0;
}

.preview-header {
  padding: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--bg-canvas-subtle);
  border-bottom: 1px solid var(--border-default);
  border-radius: var(--radius) var(--radius) 0 0;
}

.preview-header h3 {
  font-size: 14px;
  font-weight: 600;
}

.preview-actions {
  display: flex;
  gap: 8px;
}

/* GitHub Secondary Button */
.btn-secondary {
  padding: 3px 12px;
  height: 28px;
  background-color: var(--btn-bg);
  color: var(--fg-default);
  border: 1px solid var(--border-default);
  border-radius: var(--radius);
  font-size: 12px;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  transition: 0.2s;
  line-height: 20px;
}

.btn-secondary:hover {
  background-color: var(--btn-hover);
  border-color: var(--border-muted);
}

.preview-container {
  padding: 32px;
  background-color: var(--bg-canvas);
  /* Just plain canvas */
  min-height: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.preview-placeholder {
  color: var(--fg-muted);
}

#preview img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
  /* subtle shadow for the card itself */
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
}

.embed-code {
  padding: 16px;
  background-color: var(--bg-canvas-subtle);
  border-top: 1px solid var(--border-default);
}

.embed-code.hidden {
  display: none;
}

.embed-code h4 {
  font-size: 12px;
  font-weight: 600;
  color: var(--fg-muted);
  margin-bottom: 8px;
}

.embed-code code {
  display: block;
  padding: 8px 12px;
  background-color: var(--bg-canvas-inset);
  border: 1px solid var(--border-default);
  border-radius: var(--radius);
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 12px;
  color: var(--fg-default);
  word-break: break-all;
  white-space: pre-wrap;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  left: 24px;
  background: var(--bg-canvas-subtle);
  border: 1px solid var(--border-default);
  padding: 12px 16px;
  border-radius: var(--radius);
  color: var(--fg-default);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
  transform: translateY(100px);
  opacity: 0;
  transition: transform 0.3s, opacity 0.3s;
  z-index: 100;
  font-size: 13px;
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

.toast.success {
  border-left: 4px solid var(--success-fg);
}

.toast.error {
  border-left: 4px solid var(--danger-fg);
}

/* Spinner */
.loading {
  display: inline-block;
  width: 16px;
  height: 16px;
  border: 2px solid var(--border-default);
  border-top-color: var(--fg-muted);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  vertical-align: middle;
}

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

@media (max-width: 800px) {
  .main {
    grid-template-columns: 1fr;
  }

  .config-panel {
    position: static;
  }
}