:root {
  /* Background */
  --color-background-primary: #ffffff;
  --color-background-secondary: #f7f8fa;
  --color-background-tertiary: #eef0f3;
  --color-background-hover: #f0f2f5;
  --color-background-active: #e4e7eb;
  --color-background-overlay: rgba(0, 0, 0, 0.45);

  /* Surface */
  --color-surface-primary: #ffffff;
  --color-surface-secondary: #fafbfc;
  --color-surface-elevated: #ffffff;

  /* Text */
  --color-text-primary: #1f2328;
  --color-text-secondary: #656d76;
  --color-text-tertiary: #9198a0;
  --color-text-inverse: #ffffff;
  --color-text-link: #5b67f1;
  --color-text-disabled: #b0b4ba;

  /* Accent */
  --color-accent-primary: #5b67f1;
  --color-accent-primary-hover: #4a55e0;
  --color-accent-primary-active: #3d47cc;
  --color-accent-secondary: #8b94f5;
  --color-accent-soft: #eef0ff;
  --color-accent-soft-hover: #e2e5ff;

  /* Status */
  --color-success: #2da44e;
  --color-success-soft: #dafbe3;
  --color-warning: #d4a72c;
  --color-warning-soft: #fff5c2;
  --color-error: #cf222e;
  --color-error-soft: #ffebe9;
  --color-info: #0969da;
  --color-info-soft: #ddf4ff;

  /* Border */
  --color-border-default: #e4e7eb;
  --color-border-subtle: #eef0f3;
  --color-border-focus: #5b67f1;
  --color-border-disabled: #eef0f3;

  /* Shadow */
  --shadow-sm: 0 1px 2px rgba(31, 35, 40, 0.05), 0 1px 5px rgba(31, 35, 40, 0.03);
  --shadow-md: 0 8px 22px rgba(31, 35, 40, 0.08), 0 2px 6px rgba(31, 35, 40, 0.04);
  --shadow-lg: 0 16px 36px rgba(31, 35, 40, 0.11), 0 4px 12px rgba(31, 35, 40, 0.05);
  --shadow-xl: 0 24px 64px rgba(31, 35, 40, 0.18), 0 8px 20px rgba(31, 35, 40, 0.08);

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 9px;
  --radius-lg: 13px;
  --radius-xl: 18px;
  --radius-full: 9999px;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 20px;
  --space-2xl: 28px;
  --space-3xl: 36px;

  /* Typography - UI */
  --font-ui-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', 'PingFang SC',
    'Hiragino Sans GB', 'Microsoft YaHei', Helvetica, Arial, sans-serif;
  --font-ui-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, 'Cascadia Code', monospace;

  /* Typography - Editor */
  --font-editor-sans: var(--font-ui-sans);
  --font-editor-mono: var(--font-ui-mono);
  --font-editor-size: 15px;
  --font-editor-line-height: 1.7;

  /* Font sizes */
  --font-size-xs: 12px;
  --font-size-sm: 13px;
  --font-size-md: 14px;
  --font-size-lg: 15px;
  --font-size-xl: 17px;
  --font-size-2xl: 20px;
  --font-size-3xl: 26px;

  /* Line heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.7;

  /* Z-index */
  --z-sidebar: 10;
  --z-dropdown: 100;
  --z-modal: 200;
  --z-tooltip: 300;
  --z-notification: 400;
  --z-titlebar: 500;

  /* Motion */
  --motion-fast: 120ms cubic-bezier(0.2, 0, 0, 1);
  --motion-normal: 190ms cubic-bezier(0.2, 0, 0, 1);
  --motion-slow: 260ms cubic-bezier(0.2, 0, 0, 1);

  /* Layout */
  --titlebar-height: 42px;
  --sidebar-primary-width: 58px;
  --sidebar-primary-width-expanded: 180px;
  --sidebar-secondary-width: 272px;
  --statusbar-height: 28px;
}

[data-theme='dark'] {
  --color-background-primary: #0d1117;
  --color-background-secondary: #161b22;
  --color-background-tertiary: #21262d;
  --color-background-hover: #1f2630;
  --color-background-active: #2d333b;
  --color-background-overlay: rgba(0, 0, 0, 0.65);

  --color-surface-primary: #161b22;
  --color-surface-secondary: #0d1117;
  --color-surface-elevated: #1c2128;

  --color-text-primary: #e6edf3;
  --color-text-secondary: #8b949e;
  --color-text-tertiary: #6e7681;
  --color-text-inverse: #0d1117;
  --color-text-link: #7d8bff;
  --color-text-disabled: #484f58;

  --color-accent-primary: #7d8bff;
  --color-accent-primary-hover: #909cff;
  --color-accent-primary-active: #a8b2ff;
  --color-accent-secondary: #5b67f1;
  --color-accent-soft: #1e2352;
  --color-accent-soft-hover: #2a3066;

  --color-success: #3fb950;
  --color-success-soft: #033a16;
  --color-warning: #d29922;
  --color-warning-soft: #4d3a00;
  --color-error: #f85149;
  --color-error-soft: #5c1318;
  --color-info: #58a6ff;
  --color-info-soft: #051d4d;

  --color-border-default: #30363d;
  --color-border-subtle: #21262d;
  --color-border-focus: #7d8bff;
  --color-border-disabled: #21262d;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
}

[data-theme='sepia'] {
  --color-background-primary: #fbf3df;
  --color-background-secondary: #f4e8ca;
  --color-background-tertiary: #eadbb8;
  --color-background-hover: #eee0bf;
  --color-background-active: #e3d1aa;
  --color-surface-primary: #fff8e8;
  --color-surface-secondary: #f8edd3;
  --color-surface-elevated: #fffaf0;
  --color-text-primary: #40372b;
  --color-text-secondary: #746653;
  --color-text-tertiary: #9a8a72;
  --color-border-default: #ddcfad;
  --color-border-subtle: #eadfc4;
  --color-accent-primary: #8a5b32;
  --color-accent-primary-hover: #704724;
  --color-accent-soft: #edddbd;
  --color-text-link: #7b512e;
}

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

html,
body,
#app {
  height: 100%;
  width: 100%;
  overflow: hidden;
}

body {
  font-family: var(--font-ui-sans);
  font-size: var(--font-size-md);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-background-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  user-select: none;
}

a {
  color: var(--color-text-link);
  text-decoration: none;

  &:hover {
    text-decoration: underline;
  }
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

button,
a,
input,
textarea,
select {
  -webkit-tap-highlight-color: transparent;
}

input[type='checkbox'],
input[type='radio'],
input[type='range'] {
  accent-color: var(--color-accent-primary);
}

:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

ul,
ol {
  list-style: none;
}

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

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

  &:hover {
    background: var(--color-text-tertiary);
  }
}

::-webkit-scrollbar-corner {
  background: transparent;
}

::selection {
  background: var(--color-accent-soft);
  color: var(--color-accent-primary);
}

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

[data-theme='dark'] ::selection {
  background: var(--color-accent-primary);
  color: var(--color-text-inverse);
}

@media (max-width: 900px) {
  :root {
    --sidebar-primary-width-expanded: 160px;
    --sidebar-secondary-width: 224px;
  }
}