/* thinkingcup — static frontend design system.
   CSS-variable driven, light + dark via prefers-color-scheme. Vanilla, no framework. */

:root {
  --color-background: #fafaf9;
  --color-foreground: #18181b;
  --color-surface: #ffffff;
  --color-border: #e7e5e4;
  --color-primary: #4f46e5;
  --color-primary-fg: #ffffff;
  --color-muted: #f5f5f4;
  --color-muted-fg: #57534e;
  --color-danger: #dc2626;
  --color-success: #16a34a;

  --font-size-heading: 1.5rem;
  --font-size-subheading: 0.75rem;
  --font-size-body: 0.9375rem;
  --font-size-label: 0.75rem;
  --font-size-small: 0.8125rem;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --radius: 8px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-background: #0a0a0a;
    --color-foreground: #f5f5f4;
    --color-surface: #18181b;
    --color-border: #27272a;
    --color-primary: #818cf8;
    --color-primary-fg: #0a0a0a;
    --color-muted: #27272a;
    --color-muted-fg: #a8a29e;
    --color-danger: #f87171;
    --color-success: #4ade80;
  }
}

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

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-background);
  color: var(--color-foreground);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  font-size: var(--font-size-body);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-foreground); text-underline-offset: 3px; }
code { background: var(--color-muted); padding: 1px 5px; border-radius: 4px; font-size: 0.85em; }

/* Layout */
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.centered { min-height: 100vh; display: flex; flex-direction: column; justify-content: center; align-items: center; }
.stack { display: flex; flex-direction: column; gap: 16px; }
.row { display: flex; align-items: center; gap: 12px; }
.between { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.muted { color: var(--color-muted-fg); }
.text-small { font-size: var(--font-size-small); }
.uppercase-label { font-size: var(--font-size-label); text-transform: uppercase; letter-spacing: 0.08em; color: var(--color-muted-fg); }

/* Header */
.app-header { border-bottom: 1px solid var(--color-border); background: var(--color-surface); }
.app-header .container { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { font-weight: 600; letter-spacing: -0.01em; }

/* Tabs */
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--color-border); }
.tab {
  padding: 10px 14px; font-size: var(--font-size-body); font-weight: 500;
  color: var(--color-muted-fg); text-decoration: none; border-bottom: 2px solid transparent;
  transition: color 0.15s var(--ease-out), border-color 0.15s var(--ease-out);
}
.tab:hover { color: var(--color-foreground); }
.tab.active { color: var(--color-foreground); border-bottom-color: var(--color-primary); }

/* Card */
.card {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 20px; box-shadow: 0 1px 2px rgba(0,0,0,0.04);
}
.card + .card { margin-top: 12px; }
.card-title { font-size: 1rem; font-weight: 500; margin: 0 0 4px; letter-spacing: -0.01em; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 40px; padding: 0 16px; border-radius: var(--radius); font-size: var(--font-size-body);
  font-weight: 500; border: 1px solid transparent; cursor: pointer; text-decoration: none;
  transition: background 0.15s var(--ease-out), transform 0.1s var(--ease-out), opacity 0.15s;
}
.btn:active { transform: scale(0.98); }
.btn:disabled { opacity: 0.5; pointer-events: none; }
.btn-primary { background: var(--color-primary); color: var(--color-primary-fg); }
.btn-primary:hover { opacity: 0.9; }
.btn-secondary { background: var(--color-surface); color: var(--color-foreground); border-color: var(--color-border); }
.btn-secondary:hover { background: var(--color-muted); }
.btn-danger { background: var(--color-danger); color: #fff; }
.btn-ghost { background: transparent; color: var(--color-foreground); }
.btn-ghost:hover { background: var(--color-muted); }
.btn-small { height: 32px; padding: 0 12px; font-size: var(--font-size-small); }
.btn-full { width: 100%; }

/* Forms */
.field { display: flex; flex-direction: column; gap: 6px; margin-bottom: 14px; }
.field label { font-size: var(--font-size-label); text-transform: uppercase; letter-spacing: 0.06em; color: var(--color-muted-fg); }
.field label .req { color: var(--color-danger); margin-left: 2px; }
.input, select.input, textarea.input {
  width: 100%; height: 40px; padding: 0 12px; border-radius: var(--radius);
  border: 1px solid var(--color-border); background: var(--color-surface);
  color: var(--color-foreground); font-size: var(--font-size-body); font-family: inherit;
}
textarea.input { height: auto; min-height: 80px; padding: 10px 12px; resize: vertical; }
.input:focus, select.input:focus, textarea.input:focus {
  outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 2px color-mix(in srgb, var(--color-primary) 25%, transparent);
}

/* Alerts */
.alert { padding: 10px 12px; border-radius: var(--radius); font-size: var(--font-size-small); margin: 8px 0; }
.alert-error { background: color-mix(in srgb, var(--color-danger) 12%, transparent); color: var(--color-danger); }
.alert-success { background: color-mix(in srgb, var(--color-success) 14%, transparent); color: var(--color-success); }

/* Badges */
.badge { display: inline-block; padding: 3px 8px 2px; border-radius: 999px; font-size: var(--font-size-small); background: var(--color-muted); color: var(--color-muted-fg); }

/* Auth pages */
.auth-wrap { width: 100%; max-width: 400px; }

/* Empty state */
.empty { color: var(--color-muted-fg); font-size: var(--font-size-small); padding: 8px 0; }

/* Evidence list */
.evidence { border-left: 2px solid var(--color-border); padding-left: 12px; margin-top: 12px; }
.evidence .ref { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.75rem; color: var(--color-muted-fg); }

/* Timeline */
.event { display: flex; justify-content: space-between; gap: 16px; padding: 12px 0; border-bottom: 1px solid var(--color-border); }
.event pre { margin: 4px 0 0; font-size: 0.75rem; color: var(--color-muted-fg); white-space: pre-wrap; word-break: break-word; }

/* Graph canvas */
#graph { width: 100%; height: 560px; border-radius: var(--radius); background: var(--color-surface); border: 1px solid var(--color-border); }

/* Utility spacing */
.mt-4 { margin-top: 16px; } .mt-6 { margin-top: 24px; } .mb-2 { margin-bottom: 8px; }
.grid-2 { display: grid; gap: 24px; grid-template-columns: 1fr 320px; }
@media (max-width: 720px) { .grid-2 { grid-template-columns: 1fr; } }
.spinner { display:inline-block; width:14px; height:14px; border:2px solid var(--color-border); border-top-color: var(--color-primary); border-radius:50%; animation: spin 0.7s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }