/* =============================================
   原子网络加速器 - 主样式文件
   色彩方案: 深色背景 + 橙色主色调
   ============================================= */

/* === CSS 变量 === */
:root {
  --color-bg:        #0d1117;
  --color-bg-card:   #161b22;
  --color-bg-dark:   #090e14;
  --color-primary:   #ff6b2b;
  --color-primary-d: #e55a1a;
  --color-accent:    #00d4ff;
  --color-text:      #c9d1d9;
  --color-text-dim:  #8b949e;
  --color-text-head: #f0f6fc;
  --color-border:    #21262d;
  --color-border-o:  rgba(255,107,43,0.3);
  --font-mono:       'JetBrains Mono', 'Courier New', monospace;
  --font-sans:       'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --radius:          6px;
  --transition:      0.25s ease;
}

/* === Reset === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  line-height: 1.6;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }
button { cursor: pointer; font-family: inherit; border: none; outline: none; }

/* === 工具类 === */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}
.section {
  padding: 100px 0;
}
.section-label {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-accent);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.section-label::before { content: '// '; opacity: 0.6; }
.section-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  color: var(--color-text-head);
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.section-title span { color: var(--color-primary); }
.highlight { color: var(--color-primary); }

/* =============================================
   导航栏
   ============================================= */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  background: rgba(13,17,23,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition);
}
#navbar.scrolled {
  background: rgba(13,17,23,0.97);
}
.nav-inner {
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
}
.nav-logo .logo-icon {
  width: 36px;
  height: 36px;
}
.nav-logo .logo-text {
  display: flex;
  flex-direction: column;
}
.nav-logo .logo-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-text-head);
  line-height: 1.2;
}
.nav-logo .logo-sub {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-primary);
  letter-spacing: 0.15em;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}
.nav-links a {
  font-size: 13px;
  color: var(--color-text-dim);
  transition: color var(--transition);
  font-family: var(--font-mono);
  letter-spacing: 0.05em;
}
.nav-links a:hover { color: var(--color-text-head); }
.nav-links a.faq { color: var(--color-text); }
.btn-nav {
  background: var(--color-primary);
  color: #fff !important;
  padding: 9px 20px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.03em;
  transition: background var(--transition), transform var(--transition);
}
.btn-nav:hover { background: var(--color-primary-d); transform: translateY(-1px); }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  padding: 6px;
}
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all 0.3s;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-mobile {
  display: none;
  position: fixed;
  top: 64px; left: 0; right: 0;
  background: rgba(13,17,23,0.98);
  border-bottom: 1px solid var(--color-border);
  padding: 20px 24px;
  flex-direction: column;
  gap: 16px;
  z-index: 999;
}
.nav-mobile.open { display: flex; }
.nav-mobile a {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-text-dim);
  padding: 8px 0;
  border-bottom: 1px solid var(--color-border);
}
.nav-mobile a:last-child { border: none; }
.nav-mobile .btn-nav-m {
  background: var(--color-primary);
  color: #fff;
  text-align: center;
  padding: 12px;
  border-radius: var(--radius);
  font-weight: 600;
}

/* =============================================
   Hero 区
   ============================================= */
#hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 80px 24px 60px;
  position: relative;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}
/* 原子轨道动画背景 */
.atom-orbit {
  position: absolute;
  right: -5%;
  top: 50%;
  transform: translateY(-50%);
  width: min(70vw, 700px);
  height: min(70vw, 700px);
  opacity: 0.18;
}
.orbit-ring {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 1.5px solid var(--color-primary);
}
.orbit-ring:nth-child(1) { animation: spinA 12s linear infinite; }
.orbit-ring:nth-child(2) { animation: spinB 18s linear infinite; transform: rotate(60deg); }
.orbit-ring:nth-child(3) { animation: spinC 14s linear infinite; transform: rotate(120deg); }
.orbit-dot {
  position: absolute;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
  top: -4px; left: 50%; transform: translateX(-50%);
  box-shadow: 0 0 12px var(--color-accent);
}
.orbit-nucleus {
  position: absolute;
  width: 48px; height: 48px;
  border-radius: 50%;
  background: radial-gradient(circle, #ff8c50 0%, var(--color-primary) 50%, transparent 70%);
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  box-shadow: 0 0 60px rgba(255,107,43,0.5);
}

@keyframes spinA {
  from { transform: rotate(0deg) scaleY(0.35); }
  to   { transform: rotate(360deg) scaleY(0.35); }
}
@keyframes spinB {
  from { transform: rotate(60deg) scaleY(0.35); }
  to   { transform: rotate(420deg) scaleY(0.35); }
}
@keyframes spinC {
  from { transform: rotate(120deg) scaleY(0.35); }
  to   { transform: rotate(480deg) scaleY(0.35); }
}

.hero-inner {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,107,43,0.1);
  border: 1px solid var(--color-border-o);
  border-radius: 20px;
  padding: 5px 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-primary);
  letter-spacing: 0.1em;
  margin-bottom: 24px;
}
.hero-badge .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--color-primary);
  animation: blink 1.5s ease-in-out infinite;
}
@keyframes blink { 0%,100%{opacity:1} 50%{opacity:0.2} }

.hero-title {
  font-size: clamp(3rem, 8vw, 6.5rem);
  font-weight: 900;
  line-height: 0.95;
  letter-spacing: -0.04em;
  color: var(--color-text-head);
  margin-bottom: 16px;
}
.hero-title .line2 {
  color: var(--color-primary);
  display: block;
}
.hero-tagline {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-text-dim);
  letter-spacing: 0.12em;
  margin-bottom: 28px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.hero-tagline span { color: var(--color-text); }
.hero-tagline .sep { opacity: 0.4; }
.hero-desc {
  max-width: 540px;
  font-size: 15px;
  color: var(--color-text);
  line-height: 1.7;
  padding-left: 16px;
  border-left: 3px solid var(--color-primary);
  margin-bottom: 36px;
}
.hero-btns {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 56px;
}
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--color-primary);
  color: #fff;
  padding: 14px 28px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 4px 24px rgba(255,107,43,0.35);
}
.btn-primary:hover {
  background: var(--color-primary-d);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(255,107,43,0.5);
}
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  color: var(--color-text);
  padding: 13px 24px;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  font-size: 14px;
  font-weight: 500;
  transition: border-color var(--transition), color var(--transition), background var(--transition);
}
.btn-secondary:hover {
  border-color: var(--color-text-dim);
  color: var(--color-text-head);
  background: rgba(255,255,255,0.04);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  max-width: 640px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}
.stat-item {
  background: var(--color-bg-card);
  padding: 16px 20px;
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-text-dim);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 6px;
}
.stat-value {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
}

/* =============================================
   核心特性区
   ============================================= */
#features {
  background: var(--color-bg-dark);
}
.features-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: start;
}
.features-left { }
.features-left .section-label { margin-bottom: 12px; }
.features-left p {
  font-size: 15px;
  color: var(--color-text-dim);
  margin-top: 20px;
  max-width: 440px;
  line-height: 1.7;
}

.status-panel {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-top: 32px;
}
.status-panel-head {
  background: rgba(255,255,255,0.03);
  padding: 10px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--color-border);
}
.status-panel-head span {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
}
.status-online {
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 10px;
  color: #3fb950;
  letter-spacing: 0.1em;
}
.status-online::before {
  content: '';
  display: block;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: #3fb950;
  box-shadow: 0 0 6px #3fb950;
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.4} }
.status-panel-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--color-border);
}
.status-item {
  background: var(--color-bg-card);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.status-item .s-label {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-text-dim);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.status-item .s-val {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
}
.status-item .s-val.blue { color: var(--color-accent); }

.feat-list {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-top: 12px;
}
.feat-item {
  background: var(--color-bg-card);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 13px;
  color: var(--color-text);
  transition: background var(--transition);
}
.feat-item:hover { background: rgba(255,255,255,0.03); }
.feat-item .fi-icon {
  font-size: 16px;
  width: 24px;
  text-align: center;
  flex-shrink: 0;
}

.features-right { }
.feat-detail-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-head);
  margin-bottom: 12px;
}
.feat-detail-desc {
  font-size: 14px;
  color: var(--color-text-dim);
  line-height: 1.7;
  margin-bottom: 28px;
}
.feat-cards {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.feat-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 18px 20px;
}
.feat-card-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
}
.feat-card-icon { font-size: 18px; }
.feat-card-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-text-head);
}
.feat-card-desc {
  font-size: 13px;
  color: var(--color-text-dim);
  line-height: 1.6;
  padding-left: 28px;
}

/* =============================================
   六大优势
   ============================================= */
#advantages {
  background: var(--color-bg);
}
.adv-intro {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: end;
  margin-bottom: 60px;
}
.adv-desc {
  font-size: 15px;
  color: var(--color-text-dim);
  line-height: 1.7;
  padding-top: 20px;
}
.adv-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}
.adv-card {
  background: var(--color-bg-card);
  padding: 36px 28px;
  transition: background var(--transition);
  position: relative;
}
.adv-card:hover { background: rgba(255,255,255,0.025); }
.adv-num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.adv-icon { font-size: 28px; margin-bottom: 14px; display: block; }
.adv-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-text-head);
  margin-bottom: 10px;
}
.adv-desc-card {
  font-size: 13px;
  color: var(--color-text-dim);
  line-height: 1.65;
}
.adv-watermark {
  position: absolute;
  bottom: 16px; right: 16px;
  font-family: var(--font-mono);
  font-size: 48px;
  font-weight: 900;
  color: rgba(255,255,255,0.025);
  line-height: 1;
  pointer-events: none;
}

/* =============================================
   价格方案
   ============================================= */
#pricing {
  background: var(--color-bg-dark);
}
.pricing-notice {
  background: rgba(255,107,43,0.08);
  border: 1px solid rgba(255,107,43,0.25);
  border-radius: var(--radius);
  padding: 12px 20px;
  margin-bottom: 48px;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 13px;
  color: var(--color-text-dim);
  line-height: 1.6;
}
.pricing-notice .warn-icon { font-size: 16px; flex-shrink: 0; margin-top: 1px; }
.pricing-notice strong {
  font-family: var(--font-mono);
  color: var(--color-primary);
  font-size: 10px;
  letter-spacing: 0.1em;
}
.pricing-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}
.pricing-card {
  background: var(--color-bg-card);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  gap: 0;
}
.pricing-card.featured {
  background: rgba(255,107,43,0.07);
  border: 2px solid var(--color-primary);
  margin: -2px;
  border-radius: var(--radius);
  position: relative;
  z-index: 1;
}
.pricing-badge {
  display: inline-block;
  background: var(--color-primary);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.12em;
  padding: 4px 10px;
  border-radius: 2px;
  margin-bottom: 16px;
  text-transform: uppercase;
}
.pricing-plan-label {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
  margin-bottom: 4px;
}
.pricing-plan-name {
  font-size: 18px;
  font-weight: 800;
  color: var(--color-text-head);
  margin-bottom: 6px;
}
.pricing-sub-label {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
  margin-bottom: 20px;
}
.pricing-price-wrap {
  background: rgba(255,107,43,0.06);
  border: 1px solid rgba(255,107,43,0.2);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}
.pricing-currency {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-primary);
}
.pricing-amount {
  font-family: var(--font-mono);
  font-size: 48px;
  font-weight: 900;
  color: var(--color-primary);
  line-height: 1;
}
.pricing-period {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-text-dim);
  margin-left: 2px;
}
.pricing-features {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 28px;
  flex: 1;
}
.pricing-feat-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 13px;
  color: var(--color-text);
}
.pricing-feat-item .pf-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--color-primary);
  flex-shrink: 0;
  margin-top: 6px;
}
.pricing-feat-item .pf-dot.blue {
  background: var(--color-accent);
}
.btn-pricing {
  width: 100%;
  padding: 13px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.03em;
  transition: all var(--transition);
  font-family: var(--font-sans);
}
.btn-pricing-outline {
  background: transparent;
  color: var(--color-text-dim);
  border: 1px solid var(--color-border);
}
.btn-pricing-outline:hover {
  border-color: var(--color-text-dim);
  color: var(--color-text-head);
  background: rgba(255,255,255,0.04);
}
.btn-pricing-solid {
  background: var(--color-primary);
  color: #fff;
  border: 1px solid var(--color-primary);
  box-shadow: 0 4px 20px rgba(255,107,43,0.3);
}
.btn-pricing-solid:hover {
  background: var(--color-primary-d);
  transform: translateY(-1px);
  box-shadow: 0 8px 28px rgba(255,107,43,0.45);
}

/* =============================================
   用户评价
   ============================================= */
#reviews {
  background: var(--color-bg);
}
.reviews-intro {
  margin-bottom: 48px;
}
.reviews-intro p {
  font-size: 15px;
  color: var(--color-text-dim);
  margin-top: 14px;
}
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 2px;
}
.review-card {
  background: var(--color-bg-card);
  padding: 28px;
  position: relative;
}
.review-meta {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.review-meta .sep { opacity: 0.4; }
.review-stars {
  display: flex;
  gap: 2px;
  margin-bottom: 14px;
}
.review-stars span {
  color: var(--color-primary);
  font-size: 14px;
}
.review-stars span.gray { color: var(--color-border); }
.review-text {
  font-size: 13px;
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: 16px;
}
.review-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.review-user {
  font-size: 12px;
  color: var(--color-text-dim);
}
.review-user span {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--color-text-dim);
  opacity: 0.5;
}
.review-num {
  font-family: var(--font-mono);
  font-size: 36px;
  font-weight: 900;
  color: rgba(255,255,255,0.03);
  position: absolute;
  bottom: 12px; right: 16px;
  line-height: 1;
}

/* =============================================
   FAQ
   ============================================= */
#faq {
  background: var(--color-bg-dark);
}
.faq-grid {
  display: grid;
  grid-template-columns: 1fr 1.6fr;
  gap: 80px;
  align-items: start;
}
.faq-left { position: sticky; top: 80px; }
.faq-left p {
  font-size: 14px;
  color: var(--color-text-dim);
  line-height: 1.7;
  margin-top: 16px;
  margin-bottom: 28px;
}
.btn-faq {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--color-primary);
  color: #fff;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 700;
  transition: background var(--transition), transform var(--transition);
}
.btn-faq:hover { background: var(--color-primary-d); transform: translateY(-1px); }

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}
.faq-item {
  border-bottom: 1px solid var(--color-border);
}
.faq-item:last-child { border-bottom: none; }
.faq-q {
  width: 100%;
  background: var(--color-bg-card);
  padding: 18px 22px;
  text-align: left;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  transition: background var(--transition), color var(--transition);
  font-family: var(--font-sans);
}
.faq-q:hover { background: rgba(255,255,255,0.03); color: var(--color-text-head); }
.faq-q.open { color: var(--color-text-head); background: rgba(255,107,43,0.04); }
.faq-q .faq-icon {
  font-size: 18px;
  color: var(--color-primary);
  flex-shrink: 0;
  font-style: normal;
  line-height: 1;
  transition: transform var(--transition);
}
.faq-q.open .faq-icon { transform: rotate(45deg); }
.faq-a {
  display: none;
  background: rgba(255,107,43,0.025);
  padding: 0 22px 18px;
  font-size: 13px;
  color: var(--color-text-dim);
  line-height: 1.75;
  border-top: 1px solid var(--color-border-o);
}
.faq-a.open { display: block; }

/* =============================================
   页脚
   ============================================= */
#footer {
  background: var(--color-bg-dark);
  border-top: 1px solid var(--color-border);
  padding: 60px 24px 0;
}
.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}
.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--color-border);
}
.footer-brand .logo-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}
.footer-brand .brand-domain {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--color-primary);
  letter-spacing: 0.12em;
  margin-bottom: 16px;
}
.footer-brand p {
  font-size: 13px;
  color: var(--color-text-dim);
  line-height: 1.7;
  max-width: 280px;
}
.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--color-text-dim);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.footer-col h4::before { content: '//'; opacity: 0.4; }
.footer-col ul li {
  margin-bottom: 10px;
}
.footer-col ul li a {
  font-size: 13px;
  color: var(--color-text-dim);
  transition: color var(--transition);
}
.footer-col ul li a:hover { color: var(--color-text-head); }
.footer-bottom {
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-copy {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-text-dim);
  letter-spacing: 0.05em;
}
.footer-tags {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--color-text-dim);
  letter-spacing: 0.1em;
}
.footer-tags .tag-sep { opacity: 0.3; }
.footer-tags .tag-green { color: #3fb950; }

/* =============================================
   滚动动画
   ============================================= */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: none;
}

/* =============================================
   响应式
   ============================================= */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: 1fr; gap: 40px; }
  .adv-intro { grid-template-columns: 1fr; gap: 16px; }
  .faq-grid { grid-template-columns: 1fr; gap: 40px; }
  .faq-left { position: static; }
  .footer-top { grid-template-columns: 1fr 1fr; gap: 32px; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .section { padding: 72px 0; }
  .hero-title { font-size: clamp(2.5rem, 12vw, 4rem); }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .adv-grid { grid-template-columns: 1fr 1fr; }
  .pricing-cards { grid-template-columns: 1fr; }
  .pricing-card.featured { margin: 0; }
  .reviews-grid { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .atom-orbit { opacity: 0.08; width: 100vw; right: -20%; }
}

@media (max-width: 480px) {
  .adv-grid { grid-template-columns: 1fr; }
  .hero-btns { flex-direction: column; align-items: flex-start; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
}