/* ==========================================================
   环亚体育客户端 — /assets/site.css
   深空蓝 × 活力橙 × 电光青 ｜ 数据赛场视觉体系
   ========================================================== */

/* ---------- 1. Reset & Design Tokens ---------- */

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

:root {
  /* 色彩节奏 */
  --color-primary: #0B1F3A;
  --color-accent: #FF6A00;
  --color-silver: #C0C8D0;
  --color-dark: #071A2B;
  --color-light: #F5F7FA;
  --color-white: #FFFFFF;
  --color-mist: #B0C4DE;
  --color-cyan: #00D4FF;

  /* 字体层级（1.2 比例） */
  --font-heading: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "Microsoft YaHei", sans-serif;
  --fs-xs: 0.833rem;
  --fs-sm: 1rem;
  --fs-md: 1.2rem;
  --fs-lg: 1.44rem;
  --fs-xl: 1.728rem;
  --fs-2xl: 2.074rem;
  --fs-3xl: 2.488rem;
  --fs-display: 2.986rem;

  /* 间距 */
  --space-xs: 0.5rem;
  --space-sm: 0.875rem;
  --space-md: 1.25rem;
  --space-lg: 2rem;
  --space-xl: 3.5rem;
  --space-2xl: 5rem;

  /* 圆角 */
  --radius-sm: 0.375rem;
  --radius: 0.625rem;
  --radius-lg: 1rem;
  --radius-full: 999rem;

  /* 边界与阴影 */
  --border-hair: 1px solid rgba(192, 200, 208, 0.2);
  --border-strong: 1px solid rgba(192, 200, 208, 0.35);
  --shadow-sm: 0 1px 3px rgba(2, 10, 20, 0.3);
  --shadow-md: 0 4px 16px rgba(2, 10, 20, 0.35);
  --shadow-lg: 0 12px 40px rgba(2, 10, 20, 0.5);

  /* 动效 */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --trans-fast: 0.2s ease;
  --trans-base: 0.3s ease;
  --trans-slow: 0.6s var(--ease-out);

  /* 布局 */
  --container-width: 75rem;
  --header-top-pad: 0.875rem;
  --header-z: 100;
}

/* ---------- 2. Base ---------- */

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-top-pad) * 2 + 3.75rem);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--fs-sm);
  line-height: 1.6;
  color: var(--color-white);
  background-color: var(--color-dark);
  background-image:
    radial-gradient(ellipse 85% 50% at 75% -5%, rgba(11, 31, 58, 0.9), transparent 65%),
    radial-gradient(ellipse 60% 40% at 15% 15%, rgba(0, 212, 255, 0.06), transparent 60%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
}

main {
  display: block;
}

#main-content {
  outline: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 800;
  line-height: 1.25;
  color: var(--color-white);
  text-wrap: balance;
}

p {
  margin: 0 0 1em;
}

a {
  color: var(--color-cyan);
  text-decoration: none;
  transition: color var(--trans-fast);
}

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

ul, ol {
  list-style-position: inside;
}

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

::selection {
  background: var(--color-accent);
  color: var(--color-white);
}

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

/* ---------- 3. Utilities ---------- */

.container {
  width: 100%;
  max-width: var(--container-width);
  margin-inline: auto;
  padding-inline: 1.25rem;
}

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

.divider {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, transparent, var(--color-silver) 20%, transparent 85%);
  opacity: 0.4;
  margin: var(--space-lg) 0;
}

/* ---------- 4. Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6875rem 1.5rem;
  font-family: var(--font-heading);
  font-size: var(--fs-sm);
  font-weight: 700;
  line-height: 1.4;
  border-radius: var(--radius-full);
  border: 1px solid transparent;
  text-decoration: none;
  cursor: pointer;
  white-space: nowrap;
  transition:
    background-color var(--trans-fast),
    border-color var(--trans-fast),
    box-shadow var(--trans-fast),
    transform var(--trans-fast),
    color var(--trans-fast);
}

.btn--accent {
  background: linear-gradient(135deg, var(--color-accent), #F04E00);
  color: var(--color-white);
  box-shadow: 0 4px 16px rgba(255, 106, 0, 0.35);
}

.btn--accent:hover {
  background: linear-gradient(135deg, #FF7A1F, #FF5F00);
  box-shadow: 0 8px 24px rgba(255, 106, 0, 0.45);
  transform: translateY(-1px);
  color: var(--color-white);
}

.btn--accent:active {
  transform: translateY(0);
  box-shadow: 0 2px 8px rgba(255, 106, 0, 0.3);
}

.btn--outline {
  border-color: var(--border-strong);
  color: var(--color-mist);
  background: transparent;
}

.btn--outline:hover {
  border-color: var(--color-accent);
  color: var(--color-white);
  background: rgba(255, 106, 0, 0.08);
  transform: translateY(-1px);
}

.btn--ghost {
  color: var(--color-mist);
  background: transparent;
}

.btn--ghost:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.06);
}

.btn--sm {
  padding: 0.5rem 1.25rem;
  font-size: var(--fs-sm);
}

.btn--lg {
  padding: 0.875rem 2rem;
  font-size: var(--fs-md);
}

/* ---------- 5. Skip Link ---------- */

.skip-link {
  position: fixed;
  top: -100px;
  left: 1rem;
  z-index: 1000;
  padding: 0.625rem 1.25rem;
  background: var(--color-accent);
  color: var(--color-white);
  font-family: var(--font-heading);
  font-size: var(--fs-sm);
  font-weight: 700;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  transition: top var(--trans-fast);
}

.skip-link:focus {
  top: 1rem;
}

/* ---------- 6. Header ---------- */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--header-z);
  padding: var(--header-top-pad) 1.25rem;
  pointer-events: none;
}

.site-header__bar {
  position: relative;
  max-width: var(--container-width);
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.5rem 0.625rem 0.5rem 1rem;
  background: linear-gradient(180deg, rgba(11, 31, 58, 0.94), rgba(7, 26, 43, 0.9));
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: var(--border-hair);
  border-radius: var(--radius-full);
  box-shadow: 0 8px 32px rgba(2, 10, 20, 0.45);
  pointer-events: auto;
  transition:
    box-shadow var(--trans-base),
    background-color var(--trans-base);
}

.site-header[data-scrolled] .site-header__bar {
  background: linear-gradient(180deg, rgba(5, 18, 32, 0.96), rgba(7, 26, 43, 0.93));
  box-shadow: 0 12px 40px rgba(2, 10, 20, 0.55);
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--color-accent), var(--color-cyan));
  border-radius: 0 3px 3px 0;
  z-index: 999;
  pointer-events: none;
  transition: width 0.1s linear;
}

/* ---------- 7. Brand ---------- */

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  flex-shrink: 0;
  text-decoration: none;
}

.brand-mark {
  position: relative;
  display: inline-block;
  width: 2.5rem;
  height: 2.5rem;
  flex-shrink: 0;
}

.brand-mark__ring {
  position: absolute;
  inset: 0;
  border: 2px solid rgba(192, 200, 208, 0.35);
  border-top-color: var(--color-cyan);
  border-radius: 50%;
  transform: rotate(35deg);
}

.brand-mark__core {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0.5rem;
  height: 0.5rem;
  background: var(--color-accent);
  border-radius: 0.125rem;
  transform: translate(-50%, -50%) rotate(45deg);
  box-shadow: 0 0 12px rgba(255, 106, 0, 0.7);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  gap: 0.125rem;
}

.brand__text strong {
  font-family: var(--font-heading);
  font-size: var(--fs-md);
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--color-white);
}

.brand__text small {
  font-family: var(--font-body);
  font-size: var(--fs-xs);
  font-weight: 400;
  color: var(--color-mist);
  letter-spacing: 0.14em;
}

/* ---------- 8. Navigation ---------- */

.site-nav {
  flex: 1;
  display: flex;
  justify-content: center;
  min-width: 0;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 0.125rem;
  list-style: none;
}

.site-nav__link {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 0.875rem;
  border-radius: var(--radius-full);
  color: var(--color-mist);
  font-family: var(--font-heading);
  font-size: var(--fs-sm);
  font-weight: 600;
  line-height: 1.5;
  text-decoration: none;
  white-space: nowrap;
  transition:
    color var(--trans-fast),
    background-color var(--trans-fast);
}

.site-nav__link:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.06);
}

.site-nav__link[aria-current="page"] {
  color: var(--color-accent);
  background: rgba(255, 106, 0, 0.1);
}

.site-header__right {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

/* --- Mobile Nav Toggle --- */

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 0.3125rem;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0.625rem;
  border: var(--border-strong);
  border-radius: 0.875rem;
  background: transparent;
  cursor: pointer;
  transition:
    background-color var(--trans-fast),
    border-color var(--trans-fast);
}

.nav-toggle:hover {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 106, 0, 0.4);
}

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-silver);
  border-radius: var(--radius-full);
  transition:
    transform var(--trans-base),
    opacity var(--trans-fast),
    background-color var(--trans-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(0.35rem) rotate(45deg);
  background: var(--color-accent);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-0.35rem) rotate(-45deg);
  background: var(--color-accent);
}

/* ---------- 9. Footer ---------- */

.site-footer {
  position: relative;
  margin-top: var(--space-2xl);
  background: linear-gradient(180deg, var(--color-dark) 0%, #050D18 100%);
  border-top: var(--border-hair);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--color-accent) 20%, var(--color-cyan) 50%, transparent 80%);
  z-index: 1;
}

.site-footer::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 28rem;
  height: 100%;
  pointer-events: none;
  background: repeating-linear-gradient(
    -45deg,
    transparent,
    transparent 14px,
    rgba(0, 212, 255, 0.03) 14px,
    rgba(0, 212, 255, 0.03) 15px
  );
}

.site-footer__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.5fr;
  gap: 2.5rem;
  padding: var(--space-xl) 0 var(--space-xl);
}

.site-footer__brand .brand {
  margin-bottom: 1rem;
}

.site-footer__slogan {
  font-family: var(--font-heading);
  font-size: var(--fs-md);
  font-weight: 700;
  color: var(--color-white);
  margin: 0.5rem 0 0.75rem;
}

.site-footer__trust {
  font-size: var(--fs-xs);
  line-height: 1.7;
  color: var(--color-mist);
  max-width: 24rem;
}

.site-footer__col {
  min-width: 0;
}

.site-footer__title {
  font-family: var(--font-heading);
  font-size: var(--fs-sm);
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--color-white);
  margin-bottom: 1rem;
  padding-bottom: 0.375rem;
  border-bottom: 1px solid rgba(192, 200, 208, 0.18);
}

.site-footer__list {
  list-style: none;
  display: grid;
  gap: 0.625rem;
}

.site-footer__list a {
  color: var(--color-mist);
  font-size: var(--fs-sm);
  text-decoration: none;
  transition:
    color var(--trans-fast),
    padding-left var(--trans-fast);
}

.site-footer__list a:hover {
  color: var(--color-accent);
  padding-left: 0.25rem;
}

.site-footer__contact {
  list-style: none;
  display: grid;
  gap: 0.75rem;
}

.site-footer__contact li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0 0.75rem;
  align-items: baseline;
}

.site-footer__contact-label {
  font-size: var(--fs-xs);
  color: var(--color-silver);
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.site-footer__contact li span:last-child {
  color: var(--color-white);
  font-size: var(--fs-sm);
  word-break: break-all;
}

.site-footer__hours {
  margin-top: 0.875rem;
  font-size: var(--fs-xs);
  color: var(--color-mist);
  line-height: 1.5;
}

.site-footer__bottom {
  position: relative;
  z-index: 1;
  border-top: var(--border-hair);
  padding: 1.25rem 0;
}

.site-footer__bottom-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 1.5rem;
}

.site-footer__copyright {
  font-size: var(--fs-xs);
  color: var(--color-mist);
}

.site-footer__icp {
  font-size: var(--fs-xs);
  color: var(--color-mist);
}

/* ---------- 10. Back to Top ---------- */

.back-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 90;
  width: 3rem;
  height: 3rem;
  border-radius: 50%;
  border: var(--border-strong);
  background: rgba(7, 26, 43, 0.9);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  color: var(--color-mist);
  font-size: 1.125rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(0.5rem);
  transition:
    opacity var(--trans-base),
    transform var(--trans-base),
    visibility var(--trans-base),
    background-color var(--trans-fast),
    border-color var(--trans-fast);
}

.back-top:hover {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-white);
}

.back-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-top__icon {
  display: inline-block;
  line-height: 1;
}

/* ---------- 11. Breadcrumb ---------- */

.breadcrumb {
  padding: 1.25rem 0;
  font-size: var(--fs-xs);
  color: var(--color-mist);
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.375rem;
  list-style: none;
}

.breadcrumb__link {
  color: var(--color-mist);
  text-decoration: none;
  transition: color var(--trans-fast);
}

.breadcrumb__link:hover {
  color: var(--color-accent);
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "⁄";
  margin-right: 0.375rem;
  color: var(--color-silver);
  opacity: 0.6;
}

.breadcrumb__item [aria-current="page"] {
  color: var(--color-white);
  font-weight: 500;
}

/* ---------- 12. Section & Heading ---------- */

.section {
  padding-top: var(--space-xl);
}

.section--tight {
  padding-top: var(--space-lg);
}

.section-heading {
  max-width: 48rem;
  margin-bottom: var(--space-lg);
}

.section-heading__title {
  font-size: var(--fs-2xl);
  line-height: 1.2;
}

.section-heading__desc {
  margin-top: 0.75rem;
  font-size: var(--fs-md);
  color: var(--color-mist);
  max-width: 42rem;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  font-family: var(--font-heading);
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-cyan);
}

.eyebrow::before {
  content: "";
  display: inline-block;
  width: 1.5rem;
  height: 2px;
  background: var(--color-accent);
  transform: skewX(-30deg);
  border-radius: 1px;
}

/* ---------- 13. Cards & Grid ---------- */

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
  gap: 1.25rem;
}

.card {
  position: relative;
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  border: var(--border-hair);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  overflow: hidden;
  transition:
    transform var(--trans-base),
    border-color var(--trans-base),
    box-shadow var(--trans-base);
}

.card:hover {
  transform: translateY(-3px);
  border-color: rgba(255, 106, 0, 0.4);
  box-shadow: var(--shadow-lg);
}

.card--paper {
  background: var(--color-light);
  color: var(--color-dark);
  box-shadow: var(--shadow-sm);
  border-color: transparent;
}

.card--paper:hover {
  border-color: var(--color-accent);
}

.card__title {
  font-size: var(--fs-lg);
  line-height: 1.3;
  margin-bottom: 0.5rem;
}

.card--paper .card__title {
  color: var(--color-dark);
}

.card__desc {
  font-size: var(--fs-sm);
  color: var(--color-mist);
  line-height: 1.6;
}

.card--paper .card__desc {
  color: rgba(7, 26, 43, 0.7);
}

.card__meta {
  margin-top: 0.875rem;
  font-size: var(--fs-xs);
  color: var(--color-silver);
  letter-spacing: 0.04em;
}

/* ---------- 14. Stats & Data Viz ---------- */

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 13rem), 1fr));
  gap: 1rem;
}

.stat-card {
  position: relative;
  background: linear-gradient(135deg, rgba(11, 31, 58, 0.85), rgba(7, 26, 43, 0.92));
  border: var(--border-hair);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem 1.5rem;
  overflow: hidden;
}

.stat-card::after {
  content: "";
  position: absolute;
  right: -1.75rem;
  bottom: -1.75rem;
  width: 4.5rem;
  height: 4.5rem;
  border: 1px solid rgba(0, 212, 255, 0.25);
  border-radius: 50%;
  pointer-events: none;
}

.stat-card__number {
  font-family: var(--font-heading);
  font-size: var(--fs-2xl);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--color-accent);
}

.stat-card__number small {
  font-size: 0.55em;
  font-weight: 600;
  color: var(--color-mist);
  margin-left: 0.25em;
}

.stat-card__label {
  margin-top: 0.375rem;
  font-size: var(--fs-xs);
  letter-spacing: 0.04em;
  color: var(--color-mist);
}

.stat-card__trend {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  margin-top: 0.625rem;
  font-size: var(--fs-xs);
  font-weight: 600;
  color: var(--color-cyan);
}

.data-bar {
  height: 0.5rem;
  border-radius: var(--radius-full);
  background: rgba(192, 200, 208, 0.15);
  overflow: hidden;
}

.data-bar__fill {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--color-accent), var(--color-cyan));
  transition: width 0.6s var(--ease-out);
}

/* ---------- 15. Chips / Filter ---------- */

.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.5rem 1.125rem;
  font-family: var(--font-body);
  font-size: var(--fs-sm);
  font-weight: 500;
  line-height: 1.4;
  border-radius: var(--radius-full);
  border: var(--border-strong);
  background: transparent;
  color: var(--color-mist);
  cursor: pointer;
  transition:
    background-color var(--trans-fast),
    color var(--trans-fast),
    border-color var(--trans-fast),
    transform var(--trans-fast);
}

.chip:hover {
  border-color: var(--color-accent);
  color: var(--color-white);
}

.chip.is-active,
.chip[aria-pressed="true"] {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-white);
  font-weight: 600;
  transform: translateY(-1px);
}

[data-filter-target][data-hidden] {
  display: none;
}

/* ---------- 16. Image Frames ---------- */

.img-frame {
  position: relative;
  display: block;
  overflow: hidden;
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(192, 200, 208, 0.12), rgba(192, 200, 208, 0.02));
  border: var(--border-hair);
}

.img-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-frame--16-9 {
  aspect-ratio: 16 / 9;
}

.img-frame--4-3 {
  aspect-ratio: 4 / 3;
}

.img-frame--1-1 {
  aspect-ratio: 1 / 1;
}

.img-frame--tall {
  aspect-ratio: 3 / 4;
}

/* ---------- 17. Hero (Base) ---------- */

.hero {
  position: relative;
  padding: calc(var(--header-top-pad) * 2 + 4.5rem) 0 var(--space-xl);
}

.hero__title {
  font-size: var(--fs-display);
  line-height: 1.08;
  max-width: 14em;
  letter-spacing: -0.01em;
}

.hero__desc {
  font-size: var(--fs-md);
  color: var(--color-mist);
  max-width: 36rem;
  margin-top: 1rem;
}

/* ---------- 18. Reveal Animation ---------- */

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity 0.6s var(--ease-out),
    transform 0.6s var(--ease-out);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 19. Responsive ---------- */

@media (max-width: 62rem) {
  .site-header {
    padding: 0.75rem 1rem;
  }

  .site-header__bar {
    border-radius: var(--radius-full);
  }

  .site-nav {
    position: absolute;
    top: calc(100% + 0.75rem);
    left: 0;
    right: 0;
    flex: none;
    justify-content: normal;
    background: rgba(5, 18, 32, 0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: var(--border-hair);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 0.625rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-0.5rem);
    transition:
      opacity var(--trans-base),
      transform var(--trans-base),
      visibility var(--trans-base);
  }

  .site-nav[data-open] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .site-nav__list {
    flex-direction: column;
    gap: 0.25rem;
  }

  .site-nav__link {
    display: block;
    padding: 0.75rem 1rem;
    border-radius: 0.75rem;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .site-footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

  .site-footer__brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 36rem) {
  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .site-footer__brand {
    grid-column: auto;
  }

  .site-header__cta {
    font-size: 0;
    gap: 0;
    width: 2.75rem;
    padding-inline: 0;
  }

  .site-header__cta::after {
    content: "↓";
    font-size: 1.125rem;
    line-height: 1;
  }

  .back-top {
    right: 1rem;
    bottom: 1rem;
    width: 2.75rem;
    height: 2.75rem;
  }

  .hero {
    padding-top: calc(var(--header-top-pad) * 2 + 4rem);
  }

  .hero__title {
    font-size: var(--fs-3xl);
  }
}

/* ---------- 20. Focus & Reduced Motion ---------- */

@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;
    scroll-behavior: auto !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }

  .back-top {
    transition: none;
  }
}