/* ============================================
   米兰视讯 Site Shared Stylesheet
   /assets/site.css
   ============================================ */

/* ---------- 01 Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.75;
  background: #ffffff;
  color: #1e1e1e;
  overflow-x: hidden;
}

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

ul,
ol {
  list-style: none;
}

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

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

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
  font-weight: 700;
  line-height: 1.3;
}

::selection {
  background: #c8102e;
  color: #ffffff;
}

:focus-visible {
  outline: 3px solid #c9a063;
  outline-offset: 3px;
}

/* ---------- 02 Variables ---------- */
:root {
  --color-primary: #c8102e;
  --color-primary-dark: #9b0d24;
  --color-black: #0d0d0d;
  --color-charcoal: #1e1e1e;
  --color-gray: #6b6b6b;
  --color-gray-dark: #4a4a4a;
  --color-light: #f5f5f5;
  --color-white: #ffffff;
  --color-gold: #c9a063;
  --color-red-light: #f2d4d4;

  --font-serif: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-data: "Roboto Mono", "SFMono-Regular", Consolas, monospace;

  --container: 1200px;
  --container-pad: 24px;

  --duration: 0.3s;
  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);

  --shadow: 0 8px 30px rgba(13, 13, 13, 0.18);
  --shadow-sm: 0 2px 8px rgba(13, 13, 13, 0.16);
}

@media (max-width: 640px) {
  :root {
    --container-pad: 16px;
  }
}

/* ---------- 03 Layout ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

.section {
  padding-block: 56px;
}

.section--dark {
  background: var(--color-black);
  color: var(--color-white);
}

.section-heading {
  font-family: var(--font-serif);
  font-size: 28px;
  line-height: 1.3;
  color: var(--color-black);
}

.section--dark .section-heading,
.section-heading--light {
  color: var(--color-white);
}

#main-content {
  display: block;
  min-height: 40vh;
}

#main-content:focus {
  outline: none;
}

/* ---------- 04 Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  border: 1px solid transparent;
  border-radius: 2px;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.08em;
  line-height: 1.5;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

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

.btn--primary:hover {
  background: var(--color-primary-dark);
  box-shadow: 0 4px 16px rgba(200, 16, 46, 0.35);
}

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

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

.btn--ghost-light {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.6);
  color: var(--color-white);
}

.btn--ghost-light:hover {
  background: var(--color-white);
  color: var(--color-black);
  border-color: var(--color-white);
}

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

.btn--gold:hover {
  background: #b38748;
}

/* ---------- 05 Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 28px;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--color-gray);
}

.breadcrumb a {
  color: var(--color-gray-dark);
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb__sep {
  color: var(--color-primary);
  font-family: var(--font-data);
  font-size: 12px;
}

.breadcrumb__current {
  color: var(--color-black);
  font-weight: 500;
}

/* ---------- 06 Prose ---------- */
.prose {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.85;
  color: var(--color-gray-dark);
}

.prose h1,
.prose h2,
.prose h3,
.prose h4 {
  font-family: var(--font-serif);
  color: var(--color-black);
  margin-top: 1.6em;
  margin-bottom: 0.6em;
}

.prose h1 {
  font-size: 32px;
}

.prose h2 {
  font-size: 24px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-light);
}

.prose h3 {
  font-size: 19px;
}

.prose p {
  margin-bottom: 1em;
}

.prose a {
  color: var(--color-primary);
  border-bottom: 1px solid rgba(200, 16, 46, 0.35);
}

.prose a:hover {
  border-bottom-color: var(--color-primary);
}

.prose ul {
  margin: 1em 0;
  padding-left: 20px;
  list-style: disc;
}

.prose ol {
  margin: 1em 0;
  padding-left: 20px;
  list-style: decimal;
}

.prose li {
  margin-bottom: 6px;
}

.prose blockquote {
  margin: 1.5em 0;
  padding: 12px 20px;
  border-left: 4px solid var(--color-primary);
  background: var(--color-light);
  color: var(--color-black);
  font-family: var(--font-serif);
  font-size: 16px;
}

.prose code {
  font-family: var(--font-data);
  font-size: 0.85em;
  background: var(--color-light);
  color: var(--color-primary);
  padding: 2px 6px;
  border-radius: 2px;
}

/* ---------- 07 Grid ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
}

.grid__span-3 {
  grid-column: span 3;
}

.grid__span-4 {
  grid-column: span 4;
}

.grid__span-6 {
  grid-column: span 6;
}

.grid__span-8 {
  grid-column: span 8;
}

.grid__span-12 {
  grid-column: span 12;
}

@media (max-width: 900px) {
  .grid__span-3,
  .grid__span-4 {
    grid-column: span 6;
  }

  .grid__span-8 {
    grid-column: span 12;
  }
}

@media (max-width: 640px) {
  .grid {
    gap: 16px;
  }

  .grid__span-3,
  .grid__span-4,
  .grid__span-6,
  .grid__span-8 {
    grid-column: span 12;
  }
}

.page-grid {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 48px;
}

@media (max-width: 920px) {
  .page-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

/* ---------- 08 Tags & Chips ---------- */
.section-tag {
  display: inline-block;
  margin-bottom: 12px;
  padding: 4px 12px 4px 10px;
  background: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-data);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  line-height: 1.5;
  clip-path: polygon(0 0, 100% 0, calc(100% - 8px) 100%, 0 100%);
}

.section-tag--gold {
  background: var(--color-gold);
  color: var(--color-black);
}

.data-chip {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 4px 12px;
  background: var(--color-charcoal);
  color: var(--color-white);
  border-left: 3px solid var(--color-primary);
  font-family: var(--font-data);
  font-size: 13px;
  line-height: 1.6;
}

.data-chip__num {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-primary);
}

.data-chip--light {
  background: var(--color-light);
  color: var(--color-black);
}

.callout {
  padding: 16px 20px;
  background: var(--color-red-light);
  border-left: 3px solid var(--color-primary);
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-primary-dark);
}

/* ---------- 09 Image Frame ---------- */
.img-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--color-light);
  aspect-ratio: 16 / 9;
}

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

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

.img-frame__placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-black) 0%, var(--color-charcoal) 100%);
  color: var(--color-gray);
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.14em;
}

.img-frame__placeholder::before {
  content: "●";
  color: var(--color-primary);
  margin-right: 8px;
  font-size: 10px;
}

.img-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s var(--ease);
}

.img-frame:hover img {
  transform: scale(1.04);
}

.img-frame::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-gold));
  opacity: 0;
  transition: opacity 0.3s ease;
}

.img-frame:hover::after {
  opacity: 1;
}

/* ---------- 10 Scroll Progress ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: rgba(13, 13, 13, 0.35);
  z-index: 1000;
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--color-gold) 0%, var(--color-primary) 100%);
  transition: width 0.1s linear;
  will-change: width;
}

/* ---------- 11 Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  background: var(--color-black);
  color: var(--color-white);
  z-index: 200;
  box-shadow: 0 2px 16px rgba(13, 13, 13, 0.25);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 8px;
  z-index: 300;
  display: inline-block;
  background: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  padding: 10px 18px;
  border-radius: 2px;
  box-shadow: var(--shadow-sm);
}

.skip-link:focus {
  left: 8px;
}

.site-header__topbar {
  background: var(--color-primary);
  padding: 6px var(--container-pad);
}

.site-header__ticker {
  max-width: var(--container);
  margin-inline: auto;
  font-family: var(--font-data);
  font-size: 12px;
  line-height: 1.6;
  color: var(--color-white);
  letter-spacing: 0.03em;
  text-align: center;
}

.site-header__live {
  display: inline-block;
  margin-right: 10px;
  padding: 1px 6px;
  background: var(--color-black);
  color: var(--color-gold);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  vertical-align: 2px;
}

.site-header__masthead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-top: 18px;
  padding-bottom: 18px;
}

.site-brand {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  line-height: 1;
}

.site-brand__zh {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--color-white);
  line-height: 1.2;
}

.site-brand__zh::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 18px;
  margin-right: 10px;
  background: var(--color-primary);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 20% 100%);
  vertical-align: -2px;
}

.site-brand__accent {
  color: var(--color-primary);
  font-style: normal;
}

.site-brand__en {
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: 0.28em;
  color: var(--color-gold);
  text-transform: uppercase;
  padding-left: 18px;
}

.site-header__tagline {
  margin-left: auto;
  margin-right: 8px;
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--color-gray);
  border-left: 2px solid var(--color-primary);
  padding: 2px 0 2px 12px;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 2px;
  padding: 8px 14px;
  color: var(--color-white);
}

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav-toggle__bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-white);
  transition: transform var(--duration) var(--ease), opacity var(--duration);
}

.nav-toggle__text {
  font-size: 13px;
  letter-spacing: 0.1em;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.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(-6px) rotate(-45deg);
}

.site-nav {
  background: var(--color-charcoal);
}

.site-nav__list {
  display: flex;
  justify-content: center;
  align-items: stretch;
  flex-wrap: wrap;
}

.site-nav__item {
  position: relative;
}

.site-nav__link {
  position: relative;
  display: block;
  padding: 12px 24px;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: rgba(255, 255, 255, 0.85);
  transition: color 0.25s ease, background-color 0.25s ease;
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width 0.25s ease, left 0.25s ease;
}

.site-nav__link:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.03);
}

.site-nav__link:hover::after {
  left: 0;
  width: 100%;
}

.site-nav__link[aria-current="page"] {
  color: var(--color-white);
  background: var(--color-primary);
  background-image: linear-gradient(110deg, rgba(0, 0, 0, 0.18), transparent 40%);
  clip-path: polygon(8px 0, 100% 0, calc(100% - 8px) 100%, 0 100%);
}

/* ---------- 12 Footer ---------- */
.site-footer {
  position: relative;
  background: var(--color-black);
  color: var(--color-white);
}

.site-footer::before {
  content: "";
  display: block;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-primary) 70%, var(--color-gold) 100%);
}

.site-footer__main {
  display: grid;
  grid-template-columns: 1.5fr 1fr 0.8fr 1.3fr;
  gap: 48px;
  padding-block: 56px 44px;
}

.site-footer__brand {
  display: flex;
  flex-direction: column;
}

.site-footer__logo {
  font-family: var(--font-serif);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--color-white);
  line-height: 1.3;
}

.site-footer__tagline {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.24em;
  color: var(--color-gold);
  text-transform: uppercase;
  margin-top: 4px;
}

.site-footer__trust {
  margin-top: 16px;
  padding: 12px 16px;
  background: var(--color-charcoal);
  border-left: 3px solid var(--color-primary);
  font-size: 13px;
  line-height: 1.75;
  color: var(--color-gray);
}

.site-footer__heading {
  font-family: var(--font-serif);
  font-size: 15px;
  letter-spacing: 0.14em;
  color: var(--color-white);
  margin-bottom: 16px;
  padding-left: 12px;
  border-left: 3px solid var(--color-primary);
  line-height: 1.4;
}

.site-footer__links li + li {
  margin-top: 8px;
}

.site-footer__links a {
  font-size: 14px;
  color: var(--color-gray);
  line-height: 1.4;
  transition: color 0.25s ease;
}

.site-footer__links a:hover {
  color: var(--color-white);
}

.site-footer__links a::before {
  content: "›";
  color: var(--color-primary);
  margin-right: 6px;
  font-family: var(--font-data);
  display: inline-block;
  transition: transform 0.25s ease;
}

.site-footer__links a:hover::before {
  transform: translateX(3px);
}

.site-footer__contact li {
  display: flex;
  gap: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-gray);
  padding: 4px 0;
}

.site-footer__label {
  flex-shrink: 0;
  display: inline-block;
  min-width: 32px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--color-gold);
}

.site-footer__bottom {
  background: var(--color-charcoal);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 14px 0;
}

.site-footer__bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 16px;
}

.site-footer__copyright,
.site-footer__icp {
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--color-gray);
}

/* ---------- 13 Back to Top ---------- */
.back-to-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 500;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  background: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.06em;
  line-height: 1;
  border-radius: 2px;
  box-shadow: var(--shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
}

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

.back-to-top:hover {
  background: var(--color-primary-dark);
}

.back-to-top__icon {
  font-family: var(--font-data);
  font-size: 16px;
  line-height: 1;
}

/* ---------- 14 Responsive ---------- */
@media (max-width: 900px) {
  .site-footer__main {
    grid-template-columns: 1fr 1fr;
    gap: 32px 24px;
    padding-block: 40px 32px;
  }
}

@media (max-width: 820px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-header__tagline {
    display: none;
  }

  .site-header__masthead {
    padding-top: 12px;
    padding-bottom: 12px;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    border-bottom: 2px solid var(--color-primary);
    box-shadow: var(--shadow);
    max-height: calc(100dvh - 90px);
    overflow-y: auto;
  }

  .site-nav[data-open] {
    display: block;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    padding: 6px 0;
  }

  .site-nav__item + .site-nav__item {
    border-top: 1px solid rgba(255, 255, 255, 0.07);
  }

  .site-nav__link {
    padding: 14px 24px;
    text-align: left;
  }

  .site-nav__link[aria-current="page"] {
    background: transparent;
    color: var(--color-primary);
    clip-path: none;
  }

  .site-nav__link[aria-current="page"]::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: var(--color-primary);
  }
}

@media (max-width: 640px) {
  .section {
    padding-block: 40px;
  }

  .site-header__ticker {
    font-size: 11px;
  }

  .site-brand__zh {
    font-size: 22px;
  }
}

@media (max-width: 560px) {
  .site-footer__main {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .site-footer__bottom-inner {
    flex-direction: column;
    text-align: center;
  }
}

/* ---------- 15 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;
  }

  .scroll-progress__bar {
    transition: none;
  }
}