/* ==========================================
   黑料视界 — 共享样式 Site Kit
   ========================================== */

/* ---------- 变量 ---------- */
:root {
  --hc-bg: #0a0a0f;
  --hc-bg-deep: #07070c;
  --hc-bg-surface: #131320;
  --hc-bg-raised: #1f1f3d;
  --hc-accent: #b967ff;
  --hc-accent-blue: #00d4ff;
  --hc-warning: #ff6b35;
  --hc-success: #00ff9f;
  --hc-text: #e8e8f0;
  --hc-muted: #8b8ba7;
  --hc-border: rgba(185, 103, 255, 0.22);
  --hc-border-blue: rgba(0, 212, 255, 0.3);
  --hc-font-head: 'Rajdhani', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --hc-font-body: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --hc-font-mono: 'JetBrains Mono', 'SF Mono', 'Cascadia Mono', 'Consolas', monospace;
  --hc-container-w: 1400px;
  --hc-container-pad: clamp(16px, 4vw, 40px);
  --hc-radius: 18px;
  --hc-radius-sm: 10px;
  --hc-shadow: 0 20px 60px rgba(0, 0, 0, 0.55);
  --hc-glow-purple: 0 0 24px rgba(185, 103, 255, 0.28);
  --hc-glow-blue: 0 0 20px rgba(0, 212, 255, 0.28);
  --hc-transition: 0.22s ease;
}

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

html {
  -webkit-text-size-adjust: 100%;
  line-height: 1.15;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  width: 100%;
  overflow-x: hidden;
  background:
    radial-gradient(ellipse 70% 40% at 85% -5%, rgba(185, 103, 255, 0.08), transparent),
    radial-gradient(ellipse 50% 35% at 5% 15%, rgba(0, 212, 255, 0.05), transparent),
    var(--hc-bg);
  color: var(--hc-text);
  font-family: var(--hc-font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(185, 103, 255, 0.033) 1px, transparent 1px),
    linear-gradient(90deg, rgba(185, 103, 255, 0.033) 1px, transparent 1px);
  background-size: 48px 48px;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--hc-font-head);
  line-height: 1.25;
  color: var(--hc-text);
  margin: 0 0 0.5em;
}

p {
  margin: 0 0 1em;
}

a {
  color: var(--hc-accent-blue);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

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

address {
  font-style: normal;
}

::selection {
  background: rgba(185, 103, 255, 0.3);
  color: #fff;
}

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

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
::-webkit-scrollbar-track {
  background: var(--hc-bg-deep);
}
::-webkit-scrollbar-thumb {
  background: #2a2a45;
  border-radius: 6px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(185, 103, 255, 0.6);
}

/* ---------- 主内容 ---------- */
main#main-content {
  position: relative;
  z-index: 1;
  flex: 1;
  width: 100%;
  outline: none;
}

/* ---------- 容器 ---------- */
.hc-container {
  width: min(var(--hc-container-w), calc(100% - var(--hc-container-pad) * 2));
  margin-inline: auto;
}

/* ---------- 排版工具 ---------- */
.hc-mono {
  font-family: var(--hc-font-mono);
  font-size: 0.9em;
}

.hc-text-accent {
  color: var(--hc-accent);
}

.hc-text-blue {
  color: var(--hc-accent-blue);
}

.hc-text-success {
  color: var(--hc-success);
}

.hc-overline {
  display: inline-block;
  padding: 5px 14px;
  border: 1px solid rgba(185, 103, 255, 0.28);
  border-radius: 999px;
  font-family: var(--hc-font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--hc-accent);
  background: rgba(185, 103, 255, 0.06);
}

.hc-visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  border: 0;
  white-space: nowrap;
  clip-path: inset(50%);
  overflow: hidden;
}

/* ---------- 区块头 ---------- */
.hc-section {
  position: relative;
  padding: clamp(44px, 7vw, 84px) 0;
}

.hc-section-head {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: clamp(28px, 5vw, 48px);
}

.hc-kicker {
  margin: 0;
  font-family: var(--hc-font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--hc-accent);
}

.hc-title {
  margin: 0;
  font-family: var(--hc-font-head);
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: 0.02em;
  color: var(--hc-text);
}

.hc-subtitle {
  margin: 0;
  max-width: 680px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--hc-muted);
}

/* ---------- 编号章节 ---------- */
.hc-chapter {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: 24px;
  padding: 30px 0;
  border-top: 1px solid rgba(185, 103, 255, 0.12);
}

.hc-chapter:last-of-type {
  border-bottom: 1px solid rgba(185, 103, 255, 0.12);
}

.hc-chapter-num {
  font-family: var(--hc-font-head);
  font-size: clamp(40px, 5vw, 66px);
  font-weight: 700;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--hc-accent);
  opacity: 0.9;
}

@media (max-width: 640px) {
  .hc-chapter {
    grid-template-columns: 52px 1fr;
    gap: 14px;
  }
  .hc-chapter-num {
    font-size: 34px;
  }
}

/* ---------- 网格 ---------- */
.hc-grid {
  display: grid;
  gap: 24px;
}

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

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

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

@media (max-width: 1023.98px) {
  .hc-grid-3,
  .hc-grid-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 599.98px) {
  .hc-grid-2,
  .hc-grid-3,
  .hc-grid-4 {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* ---------- 按钮 ---------- */
.hc-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: var(--hc-font-head);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-decoration: none;
  line-height: 1.2;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.hc-btn-primary {
  background: var(--hc-accent);
  color: #0a0a0f;
}

.hc-btn-primary:hover {
  background: #c891ff;
  box-shadow: var(--hc-glow-purple);
  transform: translateY(-1px);
}

.hc-btn-outline {
  background: transparent;
  border-color: rgba(185, 103, 255, 0.45);
  color: var(--hc-text);
}

.hc-btn-outline:hover {
  border-color: var(--hc-accent);
  background: rgba(185, 103, 255, 0.1);
  box-shadow: var(--hc-glow-purple);
}

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

/* ---------- 卡片 ---------- */
.hc-card {
  position: relative;
  background: var(--hc-bg-surface);
  border: 1px solid rgba(185, 103, 255, 0.16);
  border-radius: var(--hc-radius);
  padding: clamp(22px, 3vw, 30px);
  overflow: hidden;
  transition: border-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
}

.hc-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--hc-accent), transparent 60%);
  opacity: 0.4;
  transition: opacity 0.25s ease;
}

.hc-card:hover,
.hc-card:focus-within {
  border-color: rgba(185, 103, 255, 0.45);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.35), 0 0 24px rgba(185, 103, 255, 0.08);
  transform: translateY(-3px);
}

.hc-card:hover::before,
.hc-card:focus-within::before {
  opacity: 1;
}

.hc-more-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--hc-font-head);
  font-size: 14px;
  font-weight: 700;
  color: var(--hc-accent-blue);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 212, 255, 0.3);
  transition: gap 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.hc-more-link:hover {
  gap: 10px;
  color: var(--hc-accent);
  border-color: var(--hc-accent);
}

/* ---------- 标签 ---------- */
.hc-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border: 1px solid rgba(0, 212, 255, 0.4);
  border-radius: 999px;
  font-family: var(--hc-font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--hc-accent-blue);
  background: rgba(0, 212, 255, 0.06);
  white-space: nowrap;
}

.hc-tag--success {
  border-color: rgba(0, 255, 159, 0.4);
  color: var(--hc-success);
  background: rgba(0, 255, 159, 0.06);
}

.hc-tag--warn {
  border-color: rgba(255, 107, 53, 0.45);
  color: var(--hc-warning);
  background: rgba(255, 107, 53, 0.07);
}

/* ---------- 数据行 ---------- */
.hc-datum {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: 11px 0;
  border-bottom: 1px dashed rgba(139, 139, 167, 0.18);
}

.hc-datum-label {
  font-family: var(--hc-font-mono);
  font-size: 13px;
  color: var(--hc-muted);
}

.hc-datum-value {
  font-family: var(--hc-font-mono);
  font-size: 14px;
  color: var(--hc-text);
  text-align: right;
}

.hc-datum-value.is-live {
  color: var(--hc-success);
}

.hc-datum-value.is-warn {
  color: var(--hc-warning);
}

/* ---------- 面包屑 ---------- */
.hc-breadcrumb {
  padding: 20px 0 40px;
  font-family: var(--hc-font-mono);
  font-size: 13px;
  color: var(--hc-muted);
}

.hc-breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.hc-breadcrumb-link {
  color: var(--hc-muted);
  text-decoration: none;
  transition: color 0.2s ease;
}

.hc-breadcrumb-link:hover,
.hc-breadcrumb-link:focus-visible {
  color: var(--hc-accent);
}

.hc-breadcrumb-current {
  color: var(--hc-text);
}

.hc-breadcrumb-sep {
  color: rgba(139, 139, 167, 0.5);
}

/* ---------- 媒体容器 ---------- */
.hc-media {
  position: relative;
  border-radius: var(--hc-radius);
  background: #101018;
  border: 1px solid rgba(255, 255, 255, 0.06);
  overflow: hidden;
  aspect-ratio: 16 / 9;
}

.hc-media::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 0;
  background-image:
    linear-gradient(rgba(185, 103, 255, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(185, 103, 255, 0.07) 1px, transparent 1px);
  background-size: 24px 24px;
  pointer-events: none;
}

.hc-media::after {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 0;
  background: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(185, 103, 255, 0.12), transparent);
  pointer-events: none;
}

.hc-media img {
  position: absolute;
  inset: 0;
  z-index: 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hc-media--wide {
  aspect-ratio: 21 / 9;
}

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

.hc-media--square {
  aspect-ratio: 1 / 1;
}

/* ---------- Header ---------- */
.hc-skip {
  position: fixed;
  top: -64px;
  left: 16px;
  z-index: 1100;
  display: inline-flex;
  align-items: center;
  padding: 12px 22px;
  background: var(--hc-accent);
  color: #0a0a0f;
  font-family: var(--hc-font-head);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  border-radius: 0 0 14px 14px;
  box-shadow: 0 8px 24px rgba(185, 103, 255, 0.3);
  transition: top 0.2s ease;
}

.hc-skip:focus {
  top: 0;
}

.hc-header {
  position: sticky;
  top: 0;
  z-index: 200;
  width: 100%;
  padding-top: clamp(12px, 2vw, 20px);
  pointer-events: none;
}

.hc-header .hc-container {
  pointer-events: auto;
}

.hc-header-capsule {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(10px, 2vw, 28px);
  padding: 8px 8px 8px 20px;
  background: rgba(10, 10, 15, 0.82);
  -webkit-backdrop-filter: blur(20px);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(185, 103, 255, 0.28);
  border-radius: 999px;
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.45), 0 0 40px rgba(185, 103, 255, 0.06);
}

.hc-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--hc-text);
  flex-shrink: 0;
}

.hc-brand-icon {
  position: relative;
  display: inline-block;
  width: 34px;
  height: 34px;
  background: linear-gradient(135deg, var(--hc-accent) 0%, var(--hc-accent-blue) 100%);
  border-radius: 9px;
  box-shadow: 0 0 18px rgba(185, 103, 255, 0.35);
  flex-shrink: 0;
}

.hc-brand-icon::before {
  content: '';
  position: absolute;
  inset: 7px;
  border: 2px solid #0a0a0f;
  border-radius: 4px;
}

.hc-brand-icon::after {
  content: '';
  position: absolute;
  width: 4px;
  height: 4px;
  background: #0a0a0f;
  border-radius: 50%;
  top: calc(50% - 2px);
  left: calc(50% - 2px);
}

.hc-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.hc-brand-name {
  font-family: var(--hc-font-head);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--hc-text);
}

.hc-brand-tag {
  font-family: var(--hc-font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hc-accent-blue);
}

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

.hc-nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.hc-nav-link {
  position: relative;
  display: inline-block;
  padding: 9px 16px;
  font-family: var(--hc-font-head);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--hc-muted);
  text-decoration: none;
  border-radius: 999px;
  transition: color 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
}

.hc-nav-link:hover,
.hc-nav-link:focus-visible {
  color: var(--hc-text);
  background: rgba(185, 103, 255, 0.1);
}

.hc-nav-link[aria-current="page"] {
  color: var(--hc-text);
  background: rgba(185, 103, 255, 0.14);
  box-shadow: inset 0 0 0 1px rgba(185, 103, 255, 0.35);
}

.hc-btn-cta {
  background: linear-gradient(135deg, var(--hc-accent) 0%, var(--hc-accent-blue) 100%);
  color: #0a0a0f;
  padding: 10px 18px;
  flex-shrink: 0;
}

.hc-btn-cta:hover {
  box-shadow: var(--hc-glow-blue);
  transform: translateY(-1px);
}

.hc-nav-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 0;
  background: transparent;
  border: 1px solid rgba(185, 103, 255, 0.35);
  border-radius: 12px;
  cursor: pointer;
  flex-shrink: 0;
}

.hc-nav-toggle-line {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: var(--hc-text);
  transition: transform 0.25s ease, opacity 0.2s ease, background 0.25s ease;
}

.hc-nav-toggle.is-active .hc-nav-toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
  background: var(--hc-accent);
}

.hc-nav-toggle.is-active .hc-nav-toggle-line:nth-child(2) {
  opacity: 0;
}

.hc-nav-toggle.is-active .hc-nav-toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
  background: var(--hc-accent);
}

.hc-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 300;
  background: rgba(139, 139, 167, 0.12);
  pointer-events: none;
}

.hc-progress-fill {
  display: block;
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--hc-accent), var(--hc-accent-blue));
  box-shadow: 0 0 10px rgba(185, 103, 255, 0.6);
}

@media (max-width: 1023.98px) {
  .hc-header-capsule {
    border-radius: 18px;
    padding-left: 16px;
  }

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

  .hc-btn-cta {
    display: none;
  }

  .hc-nav {
    position: absolute;
    top: calc(100% + 12px);
    left: 0;
    right: 0;
    padding: 8px;
    max-height: calc(100vh - 120px);
    overflow-y: auto;
    background: rgba(10, 10, 15, 0.96);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(185, 103, 255, 0.3);
    border-radius: 18px;
    box-shadow: 0 24px 60px rgba(0, 0, 0, 0.6);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s;
    pointer-events: none;
  }

  .hc-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    pointer-events: auto;
  }

  .hc-nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .hc-nav-link {
    display: block;
    padding: 12px 16px;
    font-size: 16px;
    border-radius: 12px;
  }
}

@media (max-width: 480px) {
  .hc-header-capsule {
    padding-left: 12px;
  }

  .hc-brand-tag {
    display: none;
  }
}

/* ---------- Footer ---------- */
.hc-footer {
  position: relative;
  z-index: 1;
  width: 100%;
  margin-top: 80px;
  background:
    radial-gradient(ellipse 80% 60% at 50% 120%, rgba(185, 103, 255, 0.1), transparent),
    linear-gradient(180deg, #0a0a0f 0%, #0d0d16 100%);
  border-top: 1px solid rgba(185, 103, 255, 0.18);
}

.hc-footer-inner {
  padding: 64px 0 28px;
}

.hc-footer-main {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: 40px;
  padding-bottom: 48px;
  border-bottom: 1px dashed rgba(139, 139, 167, 0.18);
}

.hc-footer-brand {
  min-width: 0;
  padding-right: 16px;
}

.hc-footer-logo {
  margin: 0 0 8px;
  font-family: var(--hc-font-head);
  font-size: 26px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--hc-text);
}

.hc-footer-domain {
  margin: 0 0 16px;
  font-family: var(--hc-font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--hc-muted);
  opacity: 0.7;
}

.hc-footer-desc {
  max-width: 340px;
  margin: 0;
  font-family: var(--hc-font-mono);
  font-size: 13px;
  line-height: 1.8;
  color: var(--hc-muted);
  border-left: 2px solid var(--hc-accent);
  padding-left: 12px;
}

.hc-footer-col h3 {
  margin: 0 0 16px;
  font-family: var(--hc-font-head);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--hc-accent);
}

.hc-footer-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.hc-footer-list a {
  color: var(--hc-muted);
  font-size: 14px;
  text-decoration: none;
  transition: color 0.2s ease, padding-left 0.2s ease, text-shadow 0.2s ease;
}

.hc-footer-list a:hover,
.hc-footer-list a:focus-visible {
  color: var(--hc-text);
  padding-left: 4px;
  text-shadow: 0 0 12px rgba(185, 103, 255, 0.4);
}

.hc-footer-address {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--hc-muted);
}

.hc-footer-address .hc-mono {
  color: var(--hc-success);
}

.hc-footer-address .hc-footer-mail {
  font-family: var(--hc-font-mono);
  font-size: 13px;
  color: var(--hc-accent-blue);
}

.hc-footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-top: 24px;
  font-family: var(--hc-font-mono);
  font-size: 12px;
  color: var(--hc-muted);
}

.hc-footer-legal p {
  margin: 0;
}

@media (max-width: 1024px) {
  .hc-footer-main {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 40px;
  }

  .hc-footer-brand {
    grid-column: 1 / -1;
    padding-right: 0;
  }
}

@media (max-width: 600px) {
  .hc-footer-main {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .hc-footer-brand {
    grid-column: auto;
  }

  .hc-footer-legal {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ---------- 返回顶部 ---------- */
.hc-back-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 400;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  padding: 0;
  background: rgba(31, 31, 61, 0.92);
  border: 1px solid rgba(185, 103, 255, 0.4);
  border-radius: 50%;
  color: var(--hc-accent);
  font-size: 18px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s, border-color 0.25s ease, box-shadow 0.25s ease, color 0.25s ease;
}

.hc-back-top:hover,
.hc-back-top:focus-visible {
  border-color: var(--hc-accent-blue);
  color: var(--hc-accent-blue);
  box-shadow: 0 0 18px rgba(0, 212, 255, 0.35);
}

.hc-back-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ---------- 无障碍与 reduced-motion ---------- */
@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;
  }

  .hc-nav {
    transition: none !important;
  }

  .hc-back-top {
    transition: none !important;
  }
}