/* App — Design Tokens and Shell Layout */

/* === DESIGN TOKENS === */

:root {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-border: #e0e0e0;
  --color-border-light: #f0f0f0;
  --color-text: #1a1a1a;
  --color-text-muted: #6b6b6b;
  --color-text-subtle: #999999;
  --color-accent: #1a1a1a;
  --color-accent-hover: #333333;
  --color-danger: #c0392b;
  --color-focus: #4a90d9;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --font-size-sm: 0.8125rem;
  --font-size-base: 0.9375rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;

  --radius: 4px;
  --transition: 150ms ease;

  --nav-width: 18rem;
}

/* === BASE === */

html {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  line-height: 1.3;
  font-weight: 600;
}

h1 { font-size: var(--font-size-xl); }
h2 { font-size: var(--font-size-lg); margin-block-start: 0; }
h3 { font-size: var(--font-size-base); margin-block-start: 0; }

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

a:hover {
  color: var(--color-accent-hover);
}

/* === APP SHELL === */

.app-shell {
  display: flex;
  min-height: 100vh;
}

/* Left nav sidebar */
.app-nav {
  position: sticky;
  top: 0;
  align-self: flex-start;
  width: var(--nav-width);
  min-width: var(--nav-width);
  height: 100vh;
  overflow-y: auto;
  border-inline-end: 1px solid var(--color-border);
  background-color: var(--color-surface);
  padding: var(--s1) var(--s0);
}

/* Main content area */
.app-main {
  flex: 1;
  min-width: 0;
  padding: var(--s2);
}

/* === UTILITY CLASSES === */

.text-muted {
  color: var(--color-text-muted);
}

.text-subtle {
  color: var(--color-text-subtle);
}

.text-sm {
  font-size: var(--font-size-sm);
}

.text-danger {
  color: var(--color-danger);
}

.visually-hidden {
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  height: 1px;
  overflow: hidden;
  position: absolute;
  white-space: nowrap;
  width: 1px;
}