/* ==========================================================================
   BIUI base styles — reset, typography, shared utilities.
   Depends on tokens.css. Load tokens.css first, then this.
   ========================================================================== */

/* ----- Reset ----- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: var(--leading-body);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg, video {
  max-width: 100%;
  height: auto;
  display: block;
}

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

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

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

/* ----- Skip link (a11y) ----- */
.skip-link {
  position: absolute;
  inset-block-start: -100px;
  inset-inline-end: 0;
  background: var(--accent);
  color: var(--bg-primary);
  padding: var(--space-3) var(--space-5);
  font-weight: 700;
  z-index: var(--z-skip);
  border-end-start-radius: var(--radius-md);
  border-end-end-radius: var(--radius-md);
  text-decoration: none;
  transition: inset-block-start var(--transition-fast);
}
.skip-link:focus { inset-block-start: 0; }

/* ----- Focus ring ----- */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

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

/* ----- Scrollbar (webkit) ----- */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover { background: var(--accent-dim); }

/* Firefox */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) var(--bg-secondary);
}

/* ----- Layout utilities ----- */
.container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--section-x);
  position: relative;
  z-index: var(--z-base);
}

.container-prose {
  max-width: var(--container-prose);
  margin-inline: auto;
  padding-inline: var(--section-x);
}

.section-padding { padding-block: var(--section-y); }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ----- Text utilities ----- */
.gradient-text {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

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

/* ----- Button utilities ----- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-base);
  line-height: 1;
  transition: transform var(--transition-base),
              box-shadow var(--transition-base),
              background var(--transition-base),
              color var(--transition-base);
  white-space: nowrap;
  cursor: pointer;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: var(--gradient-accent);
  color: var(--bg-primary);
}
.btn-primary:hover { box-shadow: var(--shadow-glow-strong); }

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}
.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ----- Tool badges (extracted from inline styles) ----- */
.tool-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  background: var(--bg-card);
  border: 1px solid var(--border);
  font-size: var(--text-sm);
  color: var(--text-secondary);
  transition: var(--transition-fast);
}
.tool-badge--sm { font-size: 0.62rem; padding: 2px var(--space-2); }
.tool-badge--primary { color: var(--accent); border-color: var(--accent-glow-strong); }

/* ----- Motion-aware scroll anchor offset ----- */
:where(h1, h2, h3, h4, section[id]) { scroll-margin-top: calc(var(--nav-height) + var(--space-4)); }