/* ==========================================================================
   快雷GO (KuaiLei GO) - 官方落地页与全站样式表
   Design System: Neo-Brutalist Minimalism / Swiss Grid
   Domain: kuailei.cfd
   ========================================================================== */

:root {
  --bg-main: #f4f1ea;
  --bg-card: #ffffff;
  --text-dark: #111111;
  --text-muted: #555555;
  --text-light: #777777;
  --brand-red: #e63946;
  --brand-yellow: #ffde00;
  --brand-yellow-light: #fff8c4;
  --border-dark: #111111;
  --border-width: 2px;
  --shadow-main: 4px 4px 0px #111111;
  --shadow-hover: 6px 6px 0px #111111;
  --shadow-small: 2px 2px 0px #111111;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
}

/* Base Resets & Dot Matrix Background */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background-color: var(--bg-main);
  background-image: radial-gradient(#d3cdc0 1px, transparent 1px);
  background-size: 20px 20px;
  color: var(--text-dark);
  font-family: var(--font-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section {
  padding: 80px 0;
  border-bottom: 2px solid var(--border-dark);
}

/* Typography & Accent Highlights */
h1, h2, h3, h4, h5 {
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.highlight-yellow {
  background-color: var(--brand-yellow);
  padding: 0 6px;
  display: inline-block;
  box-shadow: 2px 2px 0 var(--border-dark);
}

.text-red {
  color: var(--brand-red);
}

.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--brand-red);
  margin-bottom: 12px;
  position: relative;
  padding-left: 20px;
}

.section-tag::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 3px;
  background-color: var(--brand-red);
}

.section-title {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 680px;
  margin-bottom: 40px;
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-main);
  border-bottom: 2px solid var(--border-dark);
  padding: 16px 0;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--text-dark);
}

.brand-logo img {
  height: 36px;
  width: auto;
  border-radius: 4px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}

.nav-links a {
  font-weight: 700;
  font-size: 0.95rem;
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: var(--brand-red);
}

.btn-nav-recommend {
  background-color: var(--brand-yellow);
  color: var(--text-dark);
  padding: 8px 16px;
  border: 2px solid var(--border-dark);
  border-radius: var(--radius-sm);
  box-shadow: 2px 2px 0 var(--border-dark);
  font-weight: 800 !important;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn-nav-recommend:hover {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 var(--border-dark);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background-color: var(--text-dark);
  color: #ffffff;
  padding: 14px 28px;
  font-size: 1.05rem;
  font-weight: 800;
  border: 2px solid var(--border-dark);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-main);
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-primary:hover {
  background-color: var(--brand-red);
  color: #ffffff;
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-hover);
}

/* Hero Section */
.hero-section {
  padding: 80px 0 60px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 40px;
  align-items: center;
}

.hero-content {
  max-width: 650px;
}

.hero-title {
  font-size: 4.5rem;
  font-weight: 900;
  margin: 10px 0 20px;
  letter-spacing: -0.04em;
  display: flex;
  align-items: baseline;
}

.hero-desc {
  font-size: 1.15rem;
  color: #333333;
  margin-bottom: 32px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 16px;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

/* Metric Cards Grid (Matching reference screenshot) */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 30px;
}

.metric-card {
  background-color: var(--bg-card);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 16px 12px;
  text-align: center;
  transition: transform 0.15s ease;
}

.metric-card:hover {
  transform: translateY(-3px);
}

.metric-value {
  font-size: 1.8rem;
  font-weight: 900;
  color: var(--border-dark);
  line-height: 1.1;
}

.metric-value span {
  color: var(--brand-red);
}

.metric-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
  margin-top: 6px;
}

/* Feature Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.feature-card {
  background-color: var(--bg-card);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 32px 24px;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
}

.feature-card:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

.feature-icon {
  width: 48px;
  height: 48px;
  background-color: var(--brand-yellow);
  border: 2px solid var(--border-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
  box-shadow: 2px 2px 0 var(--border-dark);
}

.feature-card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Pricing Section */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background-color: var(--bg-card);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 0.2s ease;
}

.pricing-card.featured {
  background-color: #ffffff;
  border: 3px solid var(--border-dark);
  box-shadow: 6px 6px 0 var(--border-dark);
  transform: translateY(-8px);
}

.pricing-card:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

.pricing-badge {
  position: absolute;
  top: -14px;
  right: 20px;
  background-color: var(--brand-red);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 12px;
  border: 2px solid var(--border-dark);
  box-shadow: 2px 2px 0 var(--border-dark);
}

.pricing-header h3 {
  font-size: 1.4rem;
  margin-bottom: 8px;
}

.pricing-price {
  font-size: 2.5rem;
  font-weight: 900;
  margin: 16px 0;
  display: flex;
  align-items: baseline;
}

.pricing-price span {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-left: 4px;
}

.pricing-features {
  list-style: none;
  margin: 24px 0 32px;
  flex-grow: 1;
}

.pricing-features li {
  font-size: 0.95rem;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
  color: #333333;
}

.pricing-features li::before {
  content: "✓";
  font-weight: 900;
  color: var(--brand-red);
  background-color: var(--brand-yellow-light);
  border: 1px solid var(--border-dark);
  width: 20px;
  height: 20px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
}

.btn-pricing {
  width: 100%;
  text-align: center;
}

/* Articles Section */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.article-card {
  background-color: var(--bg-card);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 24px;
  display: flex;
  flex-direction: column;
  transition: all 0.2s ease;
}

.article-card:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

.article-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--text-light);
  margin-bottom: 12px;
}

.article-tag {
  background-color: var(--brand-yellow-light);
  color: var(--text-dark);
  font-weight: 700;
  padding: 2px 8px;
  border: 1px solid var(--border-dark);
}

.article-card h3 {
  font-size: 1.15rem;
  margin-bottom: 12px;
  line-height: 1.4;
}

.article-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-link {
  font-weight: 800;
  font-size: 0.9rem;
  color: var(--brand-red);
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Reviews Section */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.review-card {
  background-color: var(--bg-card);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 24px;
}

.review-stars {
  color: #f39c12;
  margin-bottom: 12px;
  font-size: 1.1rem;
}

.review-text {
  font-size: 0.95rem;
  color: #333333;
  margin-bottom: 20px;
  font-style: italic;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 12px;
}

.avatar-badge {
  width: 40px;
  height: 40px;
  background-color: var(--brand-yellow);
  border: 2px solid var(--border-dark);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
}

.user-info h4 {
  font-size: 0.95rem;
}

.user-info span {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* FAQ Accordion Section */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background-color: var(--bg-card);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  overflow: hidden;
}

.faq-question {
  padding: 20px 24px;
  font-size: 1.1rem;
  font-weight: 800;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
  background-color: #ffffff;
  transition: background-color 0.2s ease;
}

.faq-question:hover {
  background-color: #fcfbfa;
}

.faq-toggle {
  width: 24px;
  height: 24px;
  background-color: var(--brand-yellow);
  border: 2px solid var(--border-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  font-size: 1.1rem;
  transition: transform 0.3s ease;
}

.faq-item.active .faq-toggle {
  transform: rotate(45deg);
  background-color: var(--brand-red);
  color: #ffffff;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 24px;
  font-size: 0.95rem;
  color: var(--text-muted);
  background-color: #faf8f5;
  border-top: 0px solid var(--border-dark);
}

.faq-item.active .faq-answer {
  max-height: 400px;
  padding: 20px 24px;
  border-top: 2px solid var(--border-dark);
}

/* Single Article Template Specific Styles */
.article-header {
  padding: 60px 0 40px;
  background-color: #ffffff;
  border-bottom: 2px solid var(--border-dark);
}

.article-title {
  font-size: 2.5rem;
  margin: 16px 0;
  line-height: 1.25;
}

.article-body {
  background-color: #ffffff;
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 40px;
  margin: 40px 0;
  font-size: 1.05rem;
  line-height: 1.8;
}

.article-body h2 {
  font-size: 1.6rem;
  margin: 32px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--brand-yellow);
}

.article-body h3 {
  font-size: 1.3rem;
  margin: 24px 0 12px;
}

.article-body p {
  margin-bottom: 18px;
  color: #222222;
}

.article-body ul, .article-body ol {
  margin: 0 0 20px 24px;
}

.article-body li {
  margin-bottom: 8px;
}

.article-body blockquote {
  background-color: var(--brand-yellow-light);
  border-left: 4px solid var(--brand-red);
  padding: 16px 20px;
  margin: 24px 0;
  font-style: italic;
  font-weight: 500;
}

.article-body code {
  background-color: #eee;
  padding: 2px 6px;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.article-body pre {
  background-color: #111111;
  color: #00ff66;
  padding: 20px;
  border: 2px solid var(--border-dark);
  box-shadow: 4px 4px 0 var(--border-dark);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9em;
  margin: 24px 0;
}

.cta-box {
  background-color: var(--brand-yellow-light);
  border: 2px solid var(--border-dark);
  box-shadow: var(--shadow-main);
  padding: 32px;
  text-align: center;
  margin: 40px 0;
}

.cta-box h3 {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.cta-box p {
  margin-bottom: 24px;
}

/* Footer & PBN Links Section */
footer {
  background-color: #111111;
  color: #eeeeee;
  padding: 60px 0 30px;
  border-top: 2px solid var(--border-dark);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand h3 {
  font-size: 1.6rem;
  color: #ffffff;
  margin-bottom: 12px;
}

.footer-brand p {
  color: #aaaaaa;
  font-size: 0.9rem;
  max-width: 340px;
}

.footer-col h4 {
  font-size: 1rem;
  color: var(--brand-yellow);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 10px;
}

.footer-col a {
  color: #cccc00;
  color: #cccccc;
  font-size: 0.88rem;
  transition: color 0.2s ease;
}

.footer-col a:hover {
  color: #ffffff;
  text-decoration: underline;
}

/* Friend Links PBN Section */
.footer-links-pbn {
  border-top: 1px solid #333333;
  padding-top: 24px;
  margin-top: 30px;
  text-align: center;
  font-size: 0.82rem;
  color: #888888;
}

.footer-links-pbn .friend-links {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
  margin-top: 8px;
  flex-wrap: wrap;
}

.footer-links-pbn a {
  color: #aaaaaa;
  text-decoration: none;
  transition: color 0.2s ease;
}

.footer-links-pbn a:hover {
  color: var(--brand-yellow);
}

.footer-bottom {
  border-top: 1px solid #222222;
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: #666666;
}

/* Responsive Rules */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .hero-title {
    font-size: 3.5rem;
  }
  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
  }
  .hero-title {
    font-size: 2.8rem;
  }
  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .article-body {
    padding: 20px;
  }
}