* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  -webkit-user-select: none;
  user-select: none;
}

input,
textarea,
[contenteditable] {
  -webkit-user-select: text;
  user-select: text;
}

input[type="checkbox"] {
  accent-color: #6b7280;
}

:root {
  /* Colors */
  --color-dark: #1a1d1e;
  --color-accent: #00d4aa;
  --color-accent-hover: #00c49b;
  --color-accent-glow: rgba(0, 212, 170, 0.35);
  --color-border: #d0d7df;
  --color-border-subtle: #f0f3f6;
  --color-muted: #7a8694;
  --color-surface: #ffffff;
  --color-surface-hover: #f4f6f8;
  --color-surface-dim: #f6f8fa;
  --color-surface-dimmer: #eef2f6;
  --color-text-secondary: #4a5568;
  --color-text-tertiary: #5a6270;
  --color-error: #a23028;
  --color-error-bg: linear-gradient(135deg, #fef2f2 0%, #fde8e8 100%);
  --color-error-border: #f5c6c6;
  --color-warning: #92400e;
  --color-warning-bg: linear-gradient(135deg, #fffbeb 0%, #fef3c7 100%);
  --color-warning-border: #fcd34d;
  --color-danger: #c0392b;
  --color-overlay: rgba(26, 29, 30, 0.5);
  --color-border-glass: rgba(255, 255, 255, 0.8);
  --page-background: #e8ecf1;
  --rainbow-gradient: linear-gradient(90deg, #FF6B6B, #FFE66D, #4ECDC4, #A29BFE, #FF6B9D);

  /* Typography */
  --font-display: 'Poppins', sans-serif;

  /* Spacing & Sizing */
  --radius: 12px;
  --radius-sm: 8px;
  --radius-xs: 4px;
  --radius-lg: 16px;

  /* Shadows */
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.08), 0 3px 8px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.12), 0 6px 16px rgba(0, 0, 0, 0.06);
  --shadow-xl: 0 20px 48px rgba(0, 0, 0, 0.15), 0 10px 24px rgba(0, 0, 0, 0.08);
  --shadow-inset: inset 0 2px 4px rgba(0, 0, 0, 0.02);
  --shadow-inset-light: inset 0 1px 0 rgba(255, 255, 255, 0.8);
  --shadow-inset-light-subtle: inset 0 1px 0 rgba(255, 255, 255, 0.2);

  /* Gradients */
  --gradient-surface: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
  --gradient-surface-alt: linear-gradient(180deg, #ffffff 0%, #fafbfc 100%);
  --gradient-dark: linear-gradient(135deg, #2d3436 0%, #1a1d1e 100%);
  --gradient-dark-hover: linear-gradient(135deg, #3d4548 0%, #2d3436 100%);
  --gradient-accent: linear-gradient(135deg, var(--color-accent) 0%, #00c49b 100%);
  --gradient-accent-hover: linear-gradient(135deg, #00e6b8 0%, var(--color-accent) 100%);

  /* Transitions */
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);

  /* Z-index layers */
  --z-dropdown: 100;
  --z-modal: 1000;

  /* Theme-aware computed values */
  --section-card-bg: rgba(255, 255, 255, 0.5);
}

/* ==========================================================================
   Dark Theme
   ========================================================================== */

[data-theme="dark"] {
  color-scheme: dark;
  --color-dark: #eff3f8;
  --color-accent-hover: #00e6b8;
  --color-accent-glow: rgba(0, 212, 170, 0.25);
  --color-border: #2d3436;
  --color-border-subtle: #1e2426;
  --color-surface: #1a1f22;
  --color-surface-hover: #242b2f;
  --color-surface-dim: #161b1e;
  --color-surface-dimmer: #12161a;
  --color-text-secondary: #9ca3af;
  --color-text-tertiary: #8a96a4;
  --color-error: #f87171;
  --color-error-bg: linear-gradient(135deg, #2d1515 0%, #3b1a1a 100%);
  --color-error-border: #7f1d1d;
  --color-warning: #fbbf24;
  --color-warning-bg: linear-gradient(135deg, #2d2305 0%, #3b2e0a 100%);
  --color-warning-border: #78350f;
  --color-danger: #ef4444;
  --color-overlay: rgba(0, 0, 0, 0.7);
  --color-border-glass: rgba(255, 255, 255, 0.08);
  --page-background: #111518;

  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.2), 0 1px 2px rgba(0, 0, 0, 0.15);
  --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.25), 0 3px 8px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.3), 0 6px 16px rgba(0, 0, 0, 0.2);
  --shadow-xl: 0 20px 48px rgba(0, 0, 0, 0.35), 0 10px 24px rgba(0, 0, 0, 0.2);
  --shadow-inset: inset 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-inset-light: inset 0 1px 0 rgba(255, 255, 255, 0.05);
  --shadow-inset-light-subtle: inset 0 1px 0 rgba(255, 255, 255, 0.03);

  --gradient-surface: linear-gradient(180deg, #1e2426 0%, #1a1f22 100%);
  --gradient-surface-alt: linear-gradient(180deg, #1e2426 0%, #191e21 100%);
  --gradient-dark: linear-gradient(135deg, #e2e8f0 0%, #cbd5e1 100%);
  --gradient-dark-hover: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);

  --section-card-bg: rgba(255, 255, 255, 0.08);
}

body {
  min-height: 100vh;
  font-family: system-ui, -apple-system, sans-serif;
  color: var(--color-dark);
  background:
    radial-gradient(ellipse at 20% 0%, rgba(0, 212, 170, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(162, 155, 254, 0.08) 0%, transparent 50%),
    linear-gradient(160deg, #f5f7fa 0%, #e8edf3 40%, #dde4ed 100%);
  background-attachment: fixed;
}

[data-theme="dark"] body {
  background:
    radial-gradient(ellipse at 20% 0%, rgba(0, 212, 170, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(162, 155, 254, 0.06) 0%, transparent 50%),
    linear-gradient(160deg, #0f1215 0%, #111518 40%, #131719 100%);
}

/* ==========================================================================
   Base Component Styles
   ========================================================================== */

/* Shared input styles */
.input-base {
  width: 100%;
  font: 14px var(--font-display);
  color: var(--color-dark);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  outline: none;
  box-shadow: var(--shadow-md), var(--shadow-inset);
  transition: all var(--transition-normal);
}

.input-base:focus {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-lg), 0 0 0 4px var(--color-accent-glow);
}

.input-base::placeholder {
  color: var(--color-muted);
}

.input-base:disabled {
  opacity: 0.5;
}

/* Shared button styles */
.btn-base {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 16px;
  font: 600 14px var(--font-display);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition-normal);
}

.btn-base:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

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

.btn-secondary {
  color: var(--color-text-secondary);
  background: var(--gradient-surface);
  border: 2px solid var(--color-border);
  box-shadow: var(--shadow-sm), var(--shadow-inset-light);
}

.btn-secondary:hover:not(:disabled) {
  color: var(--color-dark);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md), 0 0 0 3px var(--color-accent-glow);
  transform: translateY(-2px);
}

.btn-secondary:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

.btn-primary {
  color: #fff;
  background: var(--gradient-accent);
  border: none;
  box-shadow: 0 4px 14px var(--color-accent-glow), var(--shadow-inset-light-subtle);
}

.btn-primary:hover:not(:disabled) {
  background: var(--gradient-accent-hover);
  box-shadow: 0 6px 20px var(--color-accent-glow), var(--shadow-inset-light-subtle);
  transform: translateY(-2px);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: 0 2px 8px var(--color-accent-glow);
}

/* Shared message styles */
.error-message,
.warning-message {
  padding: 10px 12px;
  margin-bottom: 8px;
  font: 14px var(--font-display);
  border-radius: var(--radius);
}

.error-message {
  color: var(--color-error);
  background: var(--color-error-bg);
  border: 1px solid var(--color-error-border);
}

.warning-message {
  color: var(--color-warning);
  background: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
}

/* Shared layout styles */
.section-card {
  padding: 16px;
  background: var(--section-card-bg);
  border-radius: var(--radius);
}

.section-card + .section-card {
  margin-top: 16px;
}

.section-label {
  margin-bottom: 12px;
  font: 600 14px var(--font-display);
  color: var(--color-dark);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.subsection-label {
  margin-top: 20px;
  margin-bottom: 10px;
  font: 500 13px var(--font-display);
  color: var(--color-text-secondary);
  letter-spacing: 0.5px;
}

.subsection-label:first-child {
  margin-top: 0;
}

/* Utility: single-line text truncation with ellipsis */
.text-truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ==========================================================================
   Theme Toggle
   ========================================================================== */

.theme-toggle {
  position: fixed;
  top: 12px;
  right: 12px;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  font-size: 18px;
  line-height: 1;
  color: var(--color-muted);
  background: var(--section-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  cursor: pointer;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.theme-toggle:hover {
  color: var(--color-dark);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md), 0 0 0 3px var(--color-accent-glow);
  transform: scale(1.1);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.theme-icon-sun { display: none; }
[data-theme="dark"] .theme-icon-sun { display: inline; }
[data-theme="dark"] .theme-icon-moon { display: none; }

/* ==========================================================================
   Accessibility
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}