/* ==========================================================================
   一分机场 (yfjichang.homes) - 1-Pixel Singularity & Monolith (极简黑白视网膜奇点)
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:ital,wght@0,300;0,400;0,600;1,400&family=Noto+Sans+SC:wght@300;400;500;700;900&display=swap');

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #fafafa;
  --bg-subtle: #f4f4f5;
  --text-main: #09090b;
  --text-muted: #71717a;
  --text-light: #a1a1aa;
  --border-color: #e4e4e7;
  --border-faint: #f4f4f5;
  --accent-black: #000000;
  --accent-gray: #27272a;
  --singularity-dot: #000000;
  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --transition-smooth: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  --shadow-subtle: 0 4px 20px rgba(0, 0, 0, 0.03);
  --shadow-hover: 0 12px 30px rgba(0, 0, 0, 0.08);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  overflow-x: hidden;
  line-height: 1.6;
  min-height: 100vh;
  position: relative;
  background: #ffffff;
}

/* Background Singularity Canvas */
#singularity-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 2;
}

/* Typography & Links */
a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-smooth);
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.3;
  word-break: keep-all;
  overflow-wrap: break-word;
}

.mono-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.mono-tag::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  background-color: var(--accent-black);
  border-radius: 50%;
}

/* Header & Nav */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  transition: var(--transition-smooth);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 72px;
}

.logo-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.03em;
}

.logo-singularity-icon {
  width: 12px;
  height: 12px;
  background: var(--accent-black);
  display: inline-block;
  position: relative;
  box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.08);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
}

.nav-link:hover {
  color: var(--text-main);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  background-color: var(--accent-black);
  color: #ffffff;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: 0px;
  border: 1px solid var(--accent-black);
  cursor: pointer;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-subtle);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.btn-primary:hover {
  background-color: #ffffff;
  color: var(--accent-black);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.12);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  background-color: transparent;
  color: var(--text-main);
  font-size: 0.875rem;
  font-weight: 600;
  border: 1px solid var(--border-color);
  transition: var(--transition-smooth);
  white-space: nowrap;
}

.btn-secondary:hover {
  border-color: var(--accent-black);
  background-color: var(--bg-secondary);
}

/* Split Left-Right Hero Section (左右结构) */
.hero-section {
  min-height: 90vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding-top: 120px;
  padding-bottom: 60px;
  overflow: hidden;
}

.hero-split-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
  width: 100%;
}

.hero-left-col {
  text-align: left;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.hero-left-col .hero-title {
  text-align: left;
  font-size: clamp(2.2rem, 3.8vw, 3.4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-top: 14px;
  margin-bottom: 20px;
  line-height: 1.2;
}

.hero-left-col .hero-subtitle {
  text-align: left;
  font-size: 1.05rem;
  color: var(--text-muted);
  margin-bottom: 28px;
  font-weight: 400;
  line-height: 1.7;
}

.hero-price-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 8px 18px;
  margin-bottom: 28px;
  font-family: var(--font-mono);
  font-size: 0.825rem;
}

.price-highlight {
  color: var(--accent-black);
  font-weight: 700;
  font-size: 1.05rem;
}

.hero-left-col .hero-cta-group {
  display: flex;
  gap: 14px;
  justify-content: flex-start;
  align-items: center;
  flex-wrap: wrap;
}

/* Right Column Visual Card */
.hero-right-col {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-visual-card {
  width: 100%;
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 24px;
  position: relative;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.05);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.origin-dot-wrapper {
  position: relative;
  width: 150px;
  height: 150px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  cursor: pointer;
}

.origin-dot {
  width: 5px;
  height: 5px;
  background-color: var(--accent-black);
  position: relative;
  z-index: 5;
  transition: transform 0.2s cubic-bezier(0.25, 1, 0.5, 1);
}

.origin-ripple-ring {
  position: absolute;
  border: 1px solid rgba(0, 0, 0, 0.15);
  border-radius: 50%;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  animation: ripple-pulse 4s infinite cubic-bezier(0.215, 0.61, 0.355, 1);
  pointer-events: none;
}

.origin-ripple-ring-2 {
  position: absolute;
  border: 1px dashed rgba(0, 0, 0, 0.1);
  border-radius: 50%;
  width: 140%;
  height: 140%;
  top: -20%;
  left: -20%;
  animation: ripple-pulse 4s infinite 2s cubic-bezier(0.215, 0.61, 0.355, 1);
  pointer-events: none;
}

@keyframes ripple-pulse {
  0% {
    transform: scale(0.2);
    opacity: 0.8;
  }
  100% {
    transform: scale(1.4);
    opacity: 0;
  }
}

.gravity-line-tag {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-light);
  white-space: nowrap;
  letter-spacing: 0.1em;
}

.gravity-line-tag.top { top: -16px; }
.gravity-line-tag.bottom { bottom: -16px; }

.hero-card-img-wrap {
  width: 100%;
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.hero-card-img-wrap img {
  width: 100%;
  height: auto;
  display: block;
  filter: grayscale(100%);
  transition: var(--transition-smooth);
}

.hero-visual-card:hover .hero-card-img-wrap img {
  filter: grayscale(0%);
}

/* Metric Ticker Grid */
.metric-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1px;
  background-color: var(--border-color);
  border: 1px solid var(--border-color);
  margin-top: 48px;
  width: 100%;
}

.metric-card {
  background-color: #ffffff;
  padding: 22px;
  text-align: left;
}

.metric-val {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-main);
}

.metric-lbl {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Section Header */
.section-padding {
  padding: 80px 0;
}

.section-header {
  margin-bottom: 48px;
}

.section-title {
  font-size: clamp(1.8rem, 3.2vw, 2.4rem);
  font-weight: 800;
  margin-top: 10px;
  line-height: 1.25;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.025rem;
  margin-top: 10px;
  max-width: 680px;
  line-height: 1.6;
}

/* Advantages Grid */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.adv-card {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  padding: 32px 26px;
  transition: var(--transition-smooth);
  position: relative;
}

.adv-card:hover {
  border-color: var(--accent-black);
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

.adv-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-light);
  margin-bottom: 16px;
  display: block;
}

.adv-title {
  font-size: 1.2rem;
  margin-bottom: 12px;
}

.adv-desc {
  color: var(--text-muted);
  font-size: 0.925rem;
  line-height: 1.65;
}

/* Pricing Section */
.pricing-section {
  background-color: #fafafa;
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition-smooth);
  position: relative;
}

.pricing-card.featured {
  border: 2px solid var(--accent-black);
  box-shadow: 0 16px 40px rgba(0,0,0,0.06);
}

.pricing-card.featured::before {
  content: '热门推荐 / 最佳性价比';
  position: absolute;
  top: -14px;
  left: 28px;
  background: var(--accent-black);
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 2px 12px;
  letter-spacing: 0.1em;
}

.plan-target {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.plan-name {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.03em;
  line-height: 1;
}

.plan-price-wrap {
  margin: 20px 0 14px 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.plan-price-num {
  font-size: 3rem;
  font-weight: 900;
  font-family: var(--font-sans);
  color: var(--text-main);
  letter-spacing: -0.04em;
  line-height: 1;
}

.plan-price-unit {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.plan-discount-info {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  padding-bottom: 20px;
  border-bottom: 1px solid #f4f4f5;
  margin-bottom: 20px;
}

.plan-features {
  list-style: none;
  margin-bottom: 28px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.plan-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-main);
}

.plan-feature-item::before {
  content: '✓';
  color: var(--accent-black);
  font-weight: bold;
}

.plan-btn {
  width: 100%;
  text-align: center;
  padding: 12px;
  font-weight: 700;
}

/* Tutorial & Guide Section */
.tutorial-tab-nav {
  display: flex;
  gap: 12px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 12px;
  overflow-x: auto;
}

.tab-btn {
  background: none;
  border: none;
  padding: 8px 16px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition-smooth);
  position: relative;
  white-space: nowrap;
}

.tab-btn.active {
  color: var(--accent-black);
}

.tab-btn.active::after {
  content: '';
  position: absolute;
  bottom: -13px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--accent-black);
}

.tutorial-content-panel {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  padding: 32px;
}

.step-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.step-item {
  display: flex;
  gap: 16px;
}

.step-num {
  width: 34px;
  height: 34px;
  background-color: var(--bg-subtle);
  color: var(--text-main);
  font-family: var(--font-mono);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.step-body h4 {
  font-size: 1.05rem;
  margin-bottom: 4px;
}

.step-body p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.code-box {
  background-color: #09090b;
  color: #a1a1aa;
  font-family: var(--font-mono);
  font-size: 0.825rem;
  padding: 12px 16px;
  margin-top: 10px;
  border-radius: 2px;
  overflow-x: auto;
}

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

.review-card {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-quote {
  font-size: 0.925rem;
  color: var(--text-main);
  line-height: 1.65;
  margin-bottom: 16px;
}

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

.avatar-initial {
  width: 34px;
  height: 34px;
  background-color: var(--accent-black);
  color: #ffffff;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
}

.author-info h5 {
  font-size: 0.875rem;
  font-weight: 700;
}

.author-info span {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* FAQ Accordion */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  border: 1px solid var(--border-color);
  background-color: #ffffff;
  transition: var(--transition-smooth);
}

.faq-question {
  padding: 18px 24px;
  font-size: 1rem;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
}

.faq-icon {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 24px;
  color: var(--text-muted);
  font-size: 0.925rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 24px 18px 24px;
  border-top: 1px dashed var(--border-color);
}

/* Articles Directory Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.article-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition-smooth);
}

.article-card:hover {
  border-color: var(--accent-black);
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.article-category {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 10px;
}

.article-title {
  font-size: 1.1rem;
  margin-bottom: 10px;
  line-height: 1.4;
}

.article-snippet {
  color: var(--text-muted);
  font-size: 0.875rem;
  line-height: 1.6;
  margin-bottom: 16px;
}

.article-meta-link {
  font-weight: 700;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--accent-black);
}

/* Article Page Specific Styling */
.article-container {
  max-width: 860px;
  margin: 110px auto 80px auto;
  padding: 0 24px;
}

.breadcrumb-nav {
  display: flex;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.breadcrumb-nav a:hover {
  color: var(--text-main);
}

.article-header {
  margin-bottom: 36px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 28px;
}

.article-header-h1 {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 800;
  margin-bottom: 16px;
  line-height: 1.25;
}

.article-meta-bar {
  display: flex;
  gap: 20px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.article-body-content {
  font-size: 1.025rem;
  line-height: 1.85;
  color: #27272a;
}

.article-body-content h2 {
  font-size: 1.6rem;
  margin: 40px 0 18px 0;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.article-body-content h3 {
  font-size: 1.25rem;
  margin: 28px 0 14px 0;
}

.article-body-content p {
  margin-bottom: 18px;
}

.article-body-content ul, .article-body-content ol {
  margin-bottom: 20px;
  padding-left: 20px;
}

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

.article-body-content blockquote {
  border-left: 3px solid var(--accent-black);
  padding: 16px 20px;
  background-color: var(--bg-secondary);
  margin: 24px 0;
  font-style: normal;
  color: var(--text-main);
}

.article-img-block {
  margin: 28px 0;
  border: 1px solid var(--border-color);
  background-color: #fafafa;
  padding: 10px;
}

.article-img-block img {
  width: 100%;
  height: auto;
  display: block;
  filter: grayscale(100%);
  transition: var(--transition-smooth);
}

.article-img-block:hover img {
  filter: grayscale(0%);
}

.article-img-caption {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  text-align: center;
  margin-top: 8px;
}

.inline-link {
  color: var(--accent-black);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.article-cta-box {
  background: var(--accent-black);
  color: #ffffff;
  padding: 36px;
  margin: 40px 0;
  text-align: center;
}

.article-cta-box h3 {
  color: #ffffff;
  font-size: 1.5rem;
  margin-bottom: 10px;
}

.article-cta-box p {
  color: #a1a1aa;
  margin-bottom: 20px;
}

.article-cta-box .btn-primary {
  background: #ffffff;
  color: #000000;
  border-color: #ffffff;
}

.article-cta-box .btn-primary:hover {
  background: #000000;
  color: #ffffff;
}

/* Related Articles Block */
.related-articles-section {
  margin-top: 56px;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

/* Clean, Spacious Monochrome Footer */
.footer {
  background-color: #000000;
  color: #a1a1aa;
  padding: 70px 0 36px 0;
  border-top: 1px solid #27272a;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-col h4 {
  color: #ffffff;
  font-size: 0.85rem;
  font-family: var(--font-mono);
  margin-bottom: 18px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: #a1a1aa;
  font-size: 0.875rem;
  transition: var(--transition-smooth);
}

.footer-links a:hover {
  color: #ffffff;
}

.footer-bottom {
  border-top: 1px solid #27272a;
  padding-top: 28px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: #71717a;
}

.footer-bottom a {
  color: #ffffff;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-bottom a:hover {
  color: #e4e4e7;
}

/* Mobile Responsive Adjustments */
@media (max-width: 960px) {
  .hero-split-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  
  .hero-section {
    padding-top: 100px;
    padding-bottom: 50px;
  }

  .origin-dot-wrapper {
    width: 130px;
    height: 130px;
  }

  .section-padding {
    padding: 50px 0;
  }

  .pricing-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}