/* ============================================================
   base.css — reset + global layout
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  min-height: 100dvh;
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
  position: relative;
}

/* 暖光氛围 — 双 radial gradient + grain noise */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 15% 10%, rgba(232, 152, 144, 0.18), transparent 60%),
    radial-gradient(ellipse 70% 50% at 90% 85%, rgba(157, 191, 170, 0.14), transparent 55%);
  pointer-events: none;
  z-index: -2;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.5 0 0 0 0 0.4 0 0 0 0 0.3 0 0 0 0.18 0'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>");
  opacity: 0.5;
  pointer-events: none;
  z-index: -1;
  mix-blend-mode: multiply;
}

[data-theme='dark'] body::before {
  background:
    radial-gradient(ellipse 80% 60% at 15% 10%, rgba(240, 163, 155, 0.12), transparent 60%),
    radial-gradient(ellipse 70% 50% at 90% 85%, rgba(176, 210, 188, 0.08), transparent 55%);
}
[data-theme='dark'] body::after {
  opacity: 0.25;
}

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

a {
  color: inherit;
  text-decoration: none;
}

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

input,
textarea,
select {
  font: inherit;
  color: inherit;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  width: 100%;
  transition: border-color var(--transition-interactive), box-shadow var(--transition-interactive);
}
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px var(--color-primary-soft);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

p {
  text-wrap: pretty;
  max-width: 64ch;
}

::selection {
  background: var(--color-primary-highlight);
  color: var(--color-text);
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

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

/* ============================================================
   Layout helpers
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--content-wide);
  margin: 0 inline auto;
  margin-left: auto;
  margin-right: auto;
  padding-inline: clamp(var(--space-6), 4vw, var(--space-12));
}
.container--narrow { max-width: var(--content-narrow); }
.container--default { max-width: var(--content-default); }

section {
  padding-block: clamp(var(--space-16), 9vw, var(--space-32));
  position: relative;
}

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--color-bg) 80%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-interactive), background var(--transition-interactive);
}
.site-header.is-scrolled {
  border-bottom-color: var(--color-divider);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  padding-block: var(--space-4);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--color-text);
}
.brand-mark { width: 32px; height: 32px; flex-shrink: 0; }
.brand-text { line-height: 1; }

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(var(--space-4), 2vw, var(--space-8));
  list-style: none;
}
.nav-links a {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-block: var(--space-2);
  position: relative;
  transition: color var(--transition-interactive);
}
.nav-links a:hover,
.nav-links a[aria-current='page'] {
  color: var(--color-text);
}
.nav-links a[aria-current='page']::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 2px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.icon-btn {
  width: 38px;
  height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  border: 1px solid transparent;
  transition: background var(--transition-interactive), color var(--transition-interactive), border-color var(--transition-interactive);
}
.icon-btn:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
}

.lang-toggle {
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 0 var(--space-3);
  height: 34px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.lang-toggle:hover {
  color: var(--color-text);
  background: var(--color-surface-offset);
}
.lang-toggle .lang-dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--color-text-faint);
}

.nav-mobile-toggle {
  display: none;
}

/* Mobile nav */
@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    inset: 64px 0 auto 0;
    background: var(--color-surface);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-6) var(--space-8);
    gap: var(--space-4);
    border-bottom: 1px solid var(--color-divider);
    transform: translateY(-110%);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: transform var(--transition-slow), opacity var(--transition-slow), visibility var(--transition-slow);
  }
  .nav-links.is-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }
  .nav-mobile-toggle {
    display: inline-flex;
  }
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.005em;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-full);
  transition: transform var(--transition-interactive), box-shadow var(--transition-interactive),
    background var(--transition-interactive), color var(--transition-interactive);
  white-space: nowrap;
  line-height: 1.2;
}
.btn--primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 8px 22px rgba(232, 152, 144, 0.3);
}
.btn--primary:hover {
  background: var(--color-primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 14px 30px rgba(232, 152, 144, 0.4);
}
.btn--ghost {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}
.btn--ghost:hover {
  background: var(--color-surface-offset);
  border-color: var(--color-text-muted);
}
.btn--lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

.btn-arrow {
  width: 14px;
  height: 14px;
  transition: transform var(--transition-interactive);
}
.btn:hover .btn-arrow { transform: translateX(3px); }

/* ============================================================
   Eyebrow tag
   ============================================================ */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary-active);
  background: var(--color-primary-soft);
  padding: 6px 14px;
  border-radius: var(--radius-full);
}
.eyebrow::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-primary);
}

/* ============================================================
   Section heading
   ============================================================ */
.section-head {
  max-width: 56ch;
  margin-bottom: clamp(var(--space-10), 5vw, var(--space-16));
}
.section-head .eyebrow { margin-bottom: var(--space-5); }
.section-head h2 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-4);
}
.section-head p {
  color: var(--color-text-muted);
  font-size: var(--text-lg);
}

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  background: var(--color-surface-offset);
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-16) var(--space-8);
  margin-top: var(--space-12);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--space-10);
  margin-bottom: var(--space-12);
}
@media (max-width: 768px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
.footer-brand p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  margin-top: var(--space-3);
}
.footer-col h4 {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: var(--space-3); }
.footer-col a {
  font-size: var(--text-sm);
  color: var(--color-text);
  transition: color var(--transition-interactive);
}
.footer-col a:hover { color: var(--color-primary-active); }

.footer-bottom {
  border-top: 1px solid var(--color-divider);
  padding-top: var(--space-6);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

/* ============================================================
   Reveal on scroll
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}
.reveal.is-visible {
  opacity: 1;
  transform: none;
}
.reveal[data-delay='1'] { transition-delay: 80ms; }
.reveal[data-delay='2'] { transition-delay: 160ms; }
.reveal[data-delay='3'] { transition-delay: 240ms; }
.reveal[data-delay='4'] { transition-delay: 320ms; }

.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;
}