frontend/src/index.css

:root {
  /* GitHub-y colours for now  */
  --color-canvas-default: #0d1117;
  --color-canvas-subtle: #161b22;
  --color-canvas-inset: #010409;
  --color-border-default: #30363d;
  --color-border-muted: #21262d;
  
  --color-fg-default: #e6edf3;
  --color-fg-muted: #7d8590;
  --color-fg-subtle: #6e7681;
  
  --color-accent-fg: #58a6ff;
  --color-accent-emphasis: #1f6feb;
  --color-success-fg: #3fb950;
  --color-attention-fg: #d29922;
  --color-danger-fg: #f85149;
  
  --color-btn-bg: #21262d;
  --color-btn-border: #363b42;
  --color-btn-hover-bg: #30363d;
  --color-btn-primary-bg: #238636;
  --color-btn-primary-hover-bg: #2ea043;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas, Liberation Mono, monospace;
  
  /* Spacing */
  --spacing-1: 4px;
  --spacing-2: 8px;
  --spacing-3: 16px;
  --spacing-4: 24px;
  --spacing-5: 32px;
  --spacing-6: 48px;
  
  /* Border radius */
  --radius-1: 6px;
  --radius-2: 12px;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 0 rgba(27, 31, 35, 0.04);
  --shadow-md: 0 3px 6px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.25);
  
  /* Transitions */
  --transition-fast: 80ms cubic-bezier(0.33, 1, 0.68, 1);
  --transition-normal: 150ms cubic-bezier(0.33, 1, 0.68, 1);
}

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

body {
  font-family: var(--font-family);
  background-color: var(--color-canvas-default);
  color: var(--color-fg-default);
  line-height: 1.5;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

#root {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Utility classes */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--spacing-3);
}

/* Button styles */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  padding: 5px 16px;
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  white-space: nowrap;
  vertical-align: middle;
  cursor: pointer;
  user-select: none;
  border: 1px solid var(--color-btn-border);
  border-radius: var(--radius-1);
  background-color: var(--color-btn-bg);
  color: var(--color-fg-default);
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.btn:hover {
  background-color: var(--color-btn-hover-bg);
  border-color: var(--color-border-default);
}

.btn:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.3);
}

.btn-primary {
  background-color: var(--color-btn-primary-bg);
  border-color: transparent;
  color: #ffffff;
}

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

.btn-lg {
  padding: 10px 24px;
  font-size: 16px;
  line-height: 24px;
}

/* Card styles */
.card {
  background-color: var(--color-canvas-subtle);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-1);
  padding: var(--spacing-4);
}

/* Input styles */
.input {
  width: 100%;
  padding: 5px 12px;
  font-size: 14px;
  line-height: 20px;
  color: var(--color-fg-default);
  background-color: var(--color-canvas-default);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-1);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input:focus {
  outline: none;
  border-color: var(--color-accent-emphasis);
  box-shadow: 0 0 0 3px rgba(31, 111, 235, 0.3);
}

.input::placeholder {
  color: var(--color-fg-subtle);
}

/* Textarea styles */
.textarea {
  width: 100%;
  min-height: 150px;
  padding: 12px;
  font-size: 14px;
  font-family: var(--font-mono);
  line-height: 1.6;
  color: var(--color-fg-default);
  background-color: var(--color-canvas-default);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-1);
  resize: vertical;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.textarea:focus {
  outline: none;
  border-color: var(--color-accent-emphasis);
  box-shadow: 0 0 0 3px rgba(31, 111, 235, 0.3);
}

/* File drop zone */
.dropzone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-3);
  padding: var(--spacing-6);
  border: 2px dashed var(--color-border-default);
  border-radius: var(--radius-2);
  background-color: var(--color-canvas-inset);
  cursor: pointer;
  transition: border-color var(--transition-normal), background-color var(--transition-normal);
}

.dropzone:hover,
.dropzone.active {
  border-color: var(--color-accent-fg);
  background-color: rgba(88, 166, 255, 0.05);
}

.dropzone-icon {
  width: 48px;
  height: 48px;
  color: var(--color-fg-muted);
}

.dropzone-text {
  font-size: 16px;
  color: var(--color-fg-muted);
  text-align: center;
}

.dropzone-hint {
  font-size: 12px;
  color: var(--color-fg-subtle);
}

/* Tabs */
.tabs {
  display: flex;
  border-bottom: 1px solid var(--color-border-default);
  margin-bottom: var(--spacing-4);
}

.tab {
  padding: var(--spacing-2) var(--spacing-3);
  font-size: 14px;
  font-weight: 500;
  color: var(--color-fg-muted);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  margin-bottom: -1px;
}

.tab:hover {
  color: var(--color-fg-default);
}

.tab.active {
  color: var(--color-fg-default);
  border-bottom-color: var(--color-accent-fg);
}

/* Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

.fade-in {
  animation: fadeIn 0.3s ease-out forwards;
}

.pulse {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-canvas-default);
}

::-webkit-scrollbar-thumb {
  background: var(--color-border-default);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-fg-subtle);
}