/* ============================================================
   9博主站 Site Kit / assets/site.css
   设计关键词：精密索引台、编辑部双层导航、刻度与细框、深海蓝与香槟金
   ============================================================ */

/* ---------- 1. Design tokens ---------- */
:root {
  --color-navy: #0A2540;
  --color-royal: #0D3B66;
  --color-gold: #D4AF37;
  --color-orange: #FF7A00;
  --color-fog: #F7F9FC;
  --color-cloud: #E5E9F0;
  --color-carbon: #1A1A2E;
  --color-cyan: #00B5D8;
  --color-violet: #7B61FF;
  --color-white: #FFFFFF;

  --font-headline: 'Source Han Sans HW', 'Noto Sans CJK SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Source Han Serif SC', 'Noto Serif CJK SC', 'Songti SC', serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --container-max: 1240px;
  --radius-sm: 3px;
  --radius-md: 6px;
  --shadow-card: 0 1px 3px rgba(10, 37, 64, 0.06);
  --shadow-lift: 0 10px 28px rgba(10, 37, 64, 0.12);
  --transition-fast: 200ms ease;
  --transition-slow: 320ms ease;
}

/* ---------- 2. Reset / base ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  -webkit-tap-highlight-color: rgba(212, 175, 55, 0.2);
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  background: var(--color-fog);
  color: var(--color-carbon);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: rgba(212, 175, 55, 0.3);
  color: var(--color-navy);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-headline);
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-navy);
}

a {
  color: var(--color-royal);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color var(--transition-fast);
}

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

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

ul,
ol {
  list-style: none;
}

button {
  font: inherit;
  color: inherit;
  background: transparent;
  border: 0;
  cursor: pointer;
}

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

#main-content {
  display: block;
  min-height: 70vh;
  scroll-margin-top: 24px;
  outline: none;
}

/* ---------- 3. Container ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: 24px;
}

@media (max-width: 640px) {
  .container {
    padding-inline: 16px;
  }
}

/* ---------- 4. Skip link ---------- */
.skip-link {
  position: fixed;
  top: -80px;
  left: 16px;
  z-index: 1200;
  display: inline-flex;
  align-items: center;
  background: var(--color-gold);
  color: var(--color-navy);
  font-family: var(--font-headline);
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  padding: 12px 20px;
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: top var(--transition-fast);
}

.skip-link:hover {
  color: var(--color-navy);
  background: #e0c04b;
}

.skip-link:focus {
  top: 16px;
}

/* ---------- 5. Header ---------- */
.site-header {
  position: relative;
  z-index: 200;
  background: var(--color-navy);
  color: var(--color-white);
  border-bottom: 1px solid rgba(212, 175, 55, 0.35);
  box-shadow: 0 4px 20px rgba(10, 37, 64, 0.1);
}

.site-header__top {
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.site-header__top-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 58px;
  padding-block: 10px;
}

.site-header__identity {
  display: flex;
  align-items: baseline;
  gap: 16px;
  min-width: 0;
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--color-white);
  font-family: var(--font-headline);
  font-size: 24px;
  font-weight: 800;
  letter-spacing: 0.08em;
  line-height: 1.2;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

.site-header__brand::before {
  content: "";
  flex: none;
  width: 10px;
  height: 10px;
  background: var(--color-gold);
  box-shadow: 0 0 0 3px rgba(212, 175, 55, 0.18);
  transition: box-shadow var(--transition-fast);
}

.site-header__brand:hover {
  color: var(--color-gold);
}

.site-header__brand:hover::before {
  box-shadow: 0 0 12px rgba(212, 175, 55, 0.6);
}

.site-header__desc {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(255, 255, 255, 0.66);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 14px;
  flex: none;
}

.site-header__cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 9px 24px;
  background: var(--color-orange);
  color: var(--color-white);
  font-family: var(--font-headline);
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  border-radius: var(--radius-sm);
  box-shadow: 0 2px 0 rgba(0, 0, 0, 0.15);
  transition: background var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
}

.site-header__cta:hover {
  background: #ff8f2e;
  color: var(--color-white);
  box-shadow: 0 6px 16px rgba(255, 122, 0, 0.35);
  transform: translateY(-1px);
}

.site-nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 11px 10px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: var(--radius-sm);
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.site-nav-toggle:hover {
  border-color: var(--color-gold);
  background: rgba(255, 255, 255, 0.04);
}

.site-nav-toggle__bar {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--color-white);
  transition: transform 280ms ease, opacity 200ms ease;
}

.site-nav-toggle[aria-expanded="true"] .site-nav-toggle__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

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

.site-nav-toggle[aria-expanded="true"] .site-nav-toggle__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.site-header__nav-bar {
  background: rgba(0, 0, 0, 0.16);
}

.site-nav {
  position: static;
  max-height: none;
  visibility: visible;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav__item {
  flex: none;
}

.site-nav__link {
  position: relative;
  display: block;
  padding: 13px 18px;
  color: rgba(255, 255, 255, 0.82);
  font-family: var(--font-headline);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.4;
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.site-nav__link:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.05);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 18px;
  right: 18px;
  bottom: -2px;
  height: 2px;
  background: var(--color-gold);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 260ms ease;
}

.site-nav__link:hover::after,
.site-nav__link:focus-visible::after {
  transform: scaleX(1);
}

.site-nav__link[aria-current="page"] {
  color: var(--color-gold);
  border-bottom-color: var(--color-gold);
}

.site-nav__link[aria-current="page"]::after {
  display: none;
}

.site-header__progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 1200;
  background: linear-gradient(90deg, var(--color-cyan) 0%, var(--color-gold) 60%, var(--color-orange) 100%);
  box-shadow: 0 0 8px rgba(0, 181, 216, 0.4);
  transform: scaleX(0);
  transform-origin: left center;
  pointer-events: none;
}

/* ---------- 6. Header responsive ---------- */
@media (max-width: 768px) {
  .site-header__top-inner {
    min-height: 54px;
    gap: 12px;
  }

  .site-header__desc {
    display: none;
  }

  .site-header__cta {
    min-height: 36px;
    padding: 8px 16px;
    font-size: 13px;
  }

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

  .site-header__nav-bar {
    background: transparent;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 100;
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    background: var(--color-navy);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    transition: max-height var(--transition-slow), visibility 0s linear var(--transition-slow);
  }

  .site-nav[data-open] {
    max-height: min(420px, 70vh);
    overflow-y: auto;
    visibility: visible;
    transition: max-height var(--transition-slow);
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0 16px;
  }

  .site-nav__item {
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  }

  .site-nav__item:last-child {
    border-bottom: 0;
  }

  .site-nav__link {
    padding: 14px 20px;
    border-left: 3px solid transparent;
    border-bottom: 0;
    white-space: normal;
  }

  .site-nav__link::after {
    display: none;
  }

  .site-nav__link[aria-current="page"] {
    border-left-color: var(--color-gold);
    background: rgba(212, 175, 55, 0.08);
  }
}

/* ---------- 7. Footer ---------- */
.site-footer {
  margin-top: 72px;
  background-color: var(--color-navy);
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.022) 1px, transparent 1px);
  background-size: 48px 48px;
  color: rgba(255, 255, 255, 0.75);
}

.site-footer::before {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--color-gold) 0%, rgba(212, 175, 55, 0.45) 30%, rgba(212, 175, 55, 0) 65%);
}

.site-footer a {
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-footer a:hover {
  color: var(--color-gold);
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.6fr;
  gap: 48px;
  padding-block: 52px 44px;
}

.site-footer__brand,
.site-footer__col,
.site-footer__contact {
  min-width: 0;
}

.site-footer__logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-headline);
  font-size: 26px;
  font-weight: 800;
  letter-spacing: 0.08em;
  color: var(--color-white);
  text-decoration: none;
}

.site-footer__logo::before {
  content: "";
  width: 10px;
  height: 10px;
  background: var(--color-gold);
  box-shadow: 0 0 0 3px rgba(212, 175, 55, 0.2);
}

.site-footer__logo:hover {
  color: var(--color-gold);
}

.site-footer__logo:hover::before {
  box-shadow: 0 0 12px rgba(212, 175, 55, 0.5);
}

.site-footer__statement {
  max-width: 320px;
  margin-top: 16px;
  font-size: 14px;
  line-height: 1.9;
  color: rgba(255, 255, 255, 0.62);
}

.site-footer__badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.site-footer__badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--color-gold);
  border: 1px solid rgba(212, 175, 55, 0.35);
  border-radius: 2px;
}

.site-footer__heading {
  font-family: var(--font-headline);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--color-gold);
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.site-footer__list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  font-size: 14px;
}

.site-footer__list a {
  display: inline-block;
  padding-block: 2px;
}

.site-footer__contact .site-footer__list {
  gap: 16px;
}

.site-footer__list--contact li {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 10px;
  align-items: start;
}

.site-footer__label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.45);
}

.site-footer__text {
  font-size: 14px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.88);
  overflow-wrap: break-word;
}

.site-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 24px;
  padding-block: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-family: var(--font-mono);
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
}

.site-footer__copyright,
.site-footer__icp {
  margin: 0;
}

/* ---------- 8. Back to top ---------- */
.back-top {
  position: fixed;
  right: 24px;
  bottom: 28px;
  z-index: 900;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 16px;
  background: var(--color-navy);
  color: var(--color-gold);
  font-family: var(--font-headline);
  font-size: 13px;
  font-weight: 600;
  line-height: 1;
  border: 1px solid rgba(212, 175, 55, 0.45);
  border-radius: var(--radius-sm);
  box-shadow: 0 6px 20px rgba(10, 37, 64, 0.3);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 260ms ease, transform 260ms ease, visibility 0s linear 260ms, background var(--transition-fast);
}

.back-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  transition: opacity 260ms ease, transform 260ms ease, visibility 0s;
}

.back-top:hover {
  background: var(--color-royal);
}

.back-top__arrow {
  font-size: 16px;
  line-height: 1;
}

.back-top__label {
  line-height: 1;
}

/* ---------- 9. Footer responsive ---------- */
@media (max-width: 992px) {
  .site-footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 640px) {
  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-block: 40px 32px;
  }

  .site-footer__bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .back-top {
    right: 16px;
    bottom: 20px;
  }
}

/* ---------- 10. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 30px;
  font-family: var(--font-headline);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
}

.btn--primary {
  background: var(--color-orange);
  color: var(--color-white);
}

.btn--primary:hover {
  background: #ff8f2e;
  color: var(--color-white);
  box-shadow: 0 8px 18px rgba(255, 122, 0, 0.3);
  transform: translateY(-1px);
}

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

.btn--ghost:hover {
  background: var(--color-navy);
  color: var(--color-white);
}

.btn--gold {
  background: var(--color-gold);
  color: var(--color-navy);
}

.btn--gold:hover {
  background: #e0c04b;
  color: var(--color-navy);
  box-shadow: 0 8px 18px rgba(212, 175, 55, 0.3);
  transform: translateY(-1px);
}

.btn--small {
  padding: 8px 18px;
  font-size: 13px;
}

/* ---------- 11. Breadcrumb ---------- */
.breadcrumb {
  margin-block: 20px 30px;
  font-size: 13px;
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "／";
  font-family: var(--font-mono);
  color: var(--color-gold);
}

.breadcrumb__link {
  color: rgba(10, 37, 64, 0.7);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.breadcrumb__item--current {
  color: var(--color-royal);
  font-weight: 600;
}

/* ---------- 12. Section helpers ---------- */
.section {
  margin-block: 52px;
}

.section-heading {
  font-size: 30px;
  line-height: 1.35;
  margin-bottom: 14px;
  letter-spacing: 0.01em;
}

.section-subheading {
  max-width: 660px;
  margin-bottom: 30px;
  font-size: 16px;
  line-height: 1.8;
  color: rgba(26, 26, 46, 0.75);
}

.index-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--color-gold);
}

.index-label::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--color-gold);
}

.tick-rule {
  display: block;
  height: 6px;
  border-bottom: 1px solid rgba(212, 175, 55, 0.3);
  background: repeating-linear-gradient(
    90deg,
    var(--color-gold) 0,
    var(--color-gold) 1px,
    transparent 1px,
    transparent 8px
  );
  opacity: 0.4;
}

.tick-rule--cyan {
  background-image: repeating-linear-gradient(
    90deg,
    var(--color-cyan) 0,
    var(--color-cyan) 1px,
    transparent 1px,
    transparent 8px
  );
}

/* ---------- 13. Grid ---------- */
.grid {
  display: grid;
  gap: 24px;
}

.grid--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid--4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.grid--12 {
  grid-template-columns: repeat(12, minmax(0, 1fr));
}

@media (max-width: 992px) {
  .grid--3,
  .grid--4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* ---------- 14. Cards ---------- */
.card {
  background: var(--color-white);
  border: 1px solid var(--color-cloud);
  border-radius: 4px;
  box-shadow: var(--shadow-card);
  padding: 28px;
  transition: border-color 260ms ease, box-shadow 260ms ease, transform 260ms ease;
}

.card:hover {
  border-color: rgba(212, 175, 55, 0.45);
  box-shadow: var(--shadow-lift);
  transform: translateY(-3px);
}

.card__title {
  font-family: var(--font-headline);
  font-size: 18px;
  margin-bottom: 10px;
}

.card__text {
  font-size: 14px;
  line-height: 1.8;
  color: rgba(26, 26, 46, 0.82);
}

/* ---------- 15. Media frame ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-cloud) 0%, var(--color-fog) 100%);
  border: 1px solid var(--color-royal);
  border-radius: 4px;
  aspect-ratio: 16 / 9;
}

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

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

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

.media-frame--empty::before {
  content: "MEDIA / 图片占位";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--color-royal);
  opacity: 0.55;
}

.media-frame--empty::after {
  content: "";
  position: absolute;
  inset: 10px;
  border: 1px dashed rgba(13, 59, 102, 0.28);
  pointer-events: none;
}

/* ---------- 16. Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto !important;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
  }
}