/* ==========================================================================
   SPACUUM — Base / reset / typography
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 16px);
}

body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.47059;
  font-weight: var(--w-regular);
  letter-spacing: -0.022em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

body.is-locked {
  overflow: hidden;
}

h1, h2, h3, h4, h5 {
  margin: 0;
  font-weight: var(--w-semibold);
  line-height: 1.08;
  letter-spacing: -0.015em;
}

p {
  margin: 0;
}

ul, ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

a {
  color: var(--c-brand);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-out);
}

a:hover {
  color: var(--c-brand-light);
}

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

input,
textarea,
select {
  font: inherit;
  color: inherit;
}

::selection {
  background: var(--c-brand);
  color: #fff;
}

:focus-visible {
  outline: 2px solid var(--c-brand-light);
  outline-offset: 3px;
}

/* ---------- Layout primitives ---------- */

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--wide {
  max-width: var(--container-wide);
}

.container--text {
  max-width: 720px;
}

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

.section--tight {
  padding-block: clamp(3rem, 6vw, 5.5rem);
}

.section--alt {
  background: var(--c-bg-alt);
}

.section--soft {
  background: var(--c-bg-soft);
}

.section--dark {
  background: var(--c-dark);
  color: var(--c-dark-ink);
}

.stack > * + * {
  margin-top: var(--space-4);
}

/* ---------- Text utilities ---------- */

.eyebrow {
  font-size: var(--fs-micro);
  font-weight: var(--w-semibold);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-brand);
}

.section--dark .eyebrow {
  color: #7fb0f0;
}

.display {
  font-size: var(--fs-display);
  font-weight: var(--w-semibold);
  line-height: 1.05;
  letter-spacing: -0.028em;
}

.hero-headline {
  font-size: var(--fs-hero);
  font-weight: var(--w-semibold);
  line-height: 0.98;
  letter-spacing: -0.035em;
}

.h1 {
  font-size: var(--fs-h1);
  letter-spacing: -0.026em;
}

.h2 {
  font-size: var(--fs-h2);
  letter-spacing: -0.022em;
  line-height: 1.1;
}

.h3 {
  font-size: var(--fs-h3);
  letter-spacing: -0.015em;
}

.lead {
  font-size: var(--fs-lead);
  line-height: 1.42;
  letter-spacing: -0.018em;
  color: var(--c-ink-2);
}

.section--dark .lead {
  color: var(--c-dark-ink-2);
}

.muted {
  color: var(--c-ink-3);
}

.small {
  font-size: var(--fs-small);
}

.mono {
  font-family: var(--font-mono);
  font-size: var(--fs-small);
  letter-spacing: 0.02em;
}

.measure {
  max-width: 62ch;
}

.text-center {
  text-align: center;
}

.text-center .measure,
.text-center .lead {
  margin-inline: auto;
}

/* ---------- Accessibility ---------- */

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

.skip-link {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translate(-50%, -120%);
  z-index: 999;
  padding: 0.75rem 1.25rem;
  background: var(--c-ink);
  color: #fff;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-size: var(--fs-small);
  transition: transform var(--dur) var(--ease-out);
}

.skip-link:focus {
  transform: translate(-50%, 0);
  color: #fff;
}

/* ---------- Reveal on scroll (Apple 式的淡入上移) ---------- */

[data-reveal] {
  opacity: 0;
  transform: translateY(26px);
  transition:
    opacity var(--dur-slow) var(--ease-out),
    transform var(--dur-slow) var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}