:root {
  --bg-deep: #0d0d1a;
  --bg-section: #111128;
  --bg-card: #1a1a3e;
  --bg-card-alt: #15152e;
  --fg: #e8e6f0;
  --fg-muted: #9997b0;
  --fg-dim: #6b698a;
  --gold: #d4a853;
  --gold-soft: #c9993f;
  --gold-glow: rgba(212, 168, 83, 0.15);
  --accent-border: rgba(212, 168, 83, 0.25);
  --serif: 'Noto Serif SC', 'Songti SC', serif;
  --sans: 'Inter', -apple-system, 'PingFang SC', sans-serif;
  --radius: 12px;
  --max-w: 1080px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg-deep);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

.gold { color: var(--gold); }

.section-label {
  font-family: var(--serif);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  color: var(--gold);
  margin-bottom: 1rem;
  letter-spacing: 0.05em;
}

.section-intro {
  font-size: 1.05rem;
  color: var(--fg-muted);
  margin-bottom: 3rem;
  max-width: 700px;
}

/* =========== LANDING NAV =========== */
.landing-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1rem 0;
  background: rgba(13, 13, 26, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

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

.app-logo {
  text-decoration: none;
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
}

.app-logo-text {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--gold);
}

.app-logo-sub {
  font-family: var(--sans);
  font-size: 0.75rem;
  color: var(--fg-dim);
  font-weight: 400;
}

.landing-nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.landing-nav-link {
  color: var(--fg-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 400;
  transition: color 0.2s;
}

.landing-nav-link:hover {
  color: var(--fg);
}

.landing-nav-cta {
  display: inline-block;
  padding: 0.45rem 1.2rem;
  background: var(--gold);
  color: var(--bg-deep);
  font-weight: 600;
  font-size: 0.85rem;
  border-radius: 6px;
  text-decoration: none;
  transition: background 0.2s;
}

.landing-nav-cta:hover {
  background: var(--gold-soft);
}

/* =========== HERO =========== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  overflow: hidden;
  background: radial-gradient(ellipse at 50% 30%, #1f1f4a 0%, var(--bg-deep) 70%);
}

.hero-bg-pattern {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.node {
  position: absolute;
  border-radius: 50%;
  background: var(--gold);
  opacity: 0.12;
}
.n1 { width: 8px; height: 8px; top: 18%; left: 22%; }
.n2 { width: 12px; height: 12px; top: 30%; right: 25%; }
.n3 { width: 6px; height: 6px; bottom: 35%; left: 15%; }
.n4 { width: 10px; height: 10px; top: 55%; right: 18%; }
.n5 { width: 7px; height: 7px; bottom: 20%; left: 40%; }
.n6 { width: 9px; height: 9px; top: 15%; right: 35%; }

.line {
  position: absolute;
  background: linear-gradient(to right, transparent, var(--gold-soft), transparent);
  opacity: 0.06;
  height: 1px;
}
.l1 { top: 25%; left: 10%; width: 35%; transform: rotate(15deg); }
.l2 { top: 40%; right: 10%; width: 30%; transform: rotate(-10deg); }
.l3 { bottom: 30%; left: 20%; width: 25%; transform: rotate(5deg); }
.l4 { top: 50%; left: 35%; width: 20%; transform: rotate(-20deg); }

.hero-content {
  position: relative;
  z-index: 1;
  padding: 2rem;
  max-width: 800px;
}

.hero-label {
  font-family: var(--serif);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.25em;
  color: var(--fg-muted);
  margin-bottom: 2rem;
}

.hero-title {
  font-family: var(--serif);
  font-size: clamp(3rem, 8vw, 5.5rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 1.5rem;
  letter-spacing: 0.02em;
}

.hero-subtitle {
  font-family: var(--serif);
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  color: var(--fg-muted);
  margin-bottom: 0;
  font-weight: 400;
}

.hero-divider {
  width: 60px;
  height: 2px;
  background: var(--gold);
  margin: 2rem auto;
}

.hero-positioning {
  font-family: var(--serif);
  font-size: 1rem;
  color: var(--fg-dim);
  line-height: 2;
  max-width: 600px;
  margin: 0 auto;
}

.hero-btn-primary {
  display: inline-block;
  padding: 0.85rem 2.5rem;
  background: var(--gold);
  color: var(--bg-deep);
  font-weight: 600;
  border-radius: 8px;
  text-decoration: none;
  font-size: 1rem;
  transition: background 0.2s, transform 0.15s;
}

.hero-btn-primary:hover {
  background: var(--gold-soft);
  transform: translateY(-1px);
}

.hero-btn-secondary {
  display: inline-block;
  padding: 0.85rem 2.5rem;
  background: rgba(255, 255, 255, 0.06);
  color: var(--fg);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  text-decoration: none;
  font-size: 1rem;
  transition: background 0.2s, border-color 0.2s;
}

.hero-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.2);
}

/* =========== IDEALS (愿景/使命/价值观) =========== */
.ideals {
  padding: 6rem 0;
  background: var(--bg-section);
}

.ideals-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.ideal-card {
  text-align: center;
  padding: 3rem 2rem;
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: var(--radius);
  transition: border-color 0.3s;
}

.ideal-card:hover {
  border-color: var(--accent-border);
}

.ideal-icon {
  font-size: 2rem;
  color: var(--gold);
  margin-bottom: 1rem;
}

.ideal-label {
  font-family: var(--serif);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--gold);
  letter-spacing: 0.15em;
  margin-bottom: 1rem;
}

.ideal-text {
  font-family: var(--serif);
  font-size: 1.2rem;
  font-weight: 600;
  line-height: 1.8;
}

/* =========== FEATURES (核心功能) =========== */
.features {
  padding: 7rem 0;
  background: var(--bg-deep);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  transition: border-color 0.3s, transform 0.2s;
}

.feature-card:hover {
  border-color: var(--accent-border);
  transform: translateY(-2px);
}

.feature-icon {
  font-size: 2.5rem;
  color: var(--gold);
  margin-bottom: 1.25rem;
}

.feature-card h3 {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.feature-card p {
  font-size: 0.95rem;
  color: var(--fg-muted);
  line-height: 1.8;
  margin-bottom: 1.5rem;
}

.feature-link {
  font-size: 0.9rem;
  color: var(--gold);
  text-decoration: none;
  font-weight: 500;
  transition: opacity 0.2s;
}

.feature-link:hover {
  opacity: 0.8;
}

/* =========== PILLARS (五大支柱) =========== */
.pillars-section {
  padding: 7rem 0;
  background: var(--bg-section);
}

.pillars-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.pillar-card {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: var(--radius);
  padding: 2rem 1.5rem;
  transition: border-color 0.3s;
}

.pillar-card:hover {
  border-color: var(--accent-border);
}

.pillar-number {
  font-family: var(--sans);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--gold);
  margin-bottom: 1rem;
  letter-spacing: 0.1em;
}

.pillar-card h3 {
  font-family: var(--serif);
  font-size: 1.3rem;
  margin-bottom: 0.75rem;
  font-weight: 700;
}

.pillar-card p {
  font-size: 0.9rem;
  color: var(--fg-muted);
  line-height: 1.7;
}

/* =========== PHILOSOPHY DEEP (理念解读 手风琴) =========== */
.philosophy-deep {
  padding: 7rem 0;
  background: var(--bg-deep);
}

.accordion {
  max-width: 800px;
}

.accordion-item {
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius);
  margin-bottom: 1rem;
  overflow: hidden;
  transition: border-color 0.3s;
}

.accordion-item:hover {
  border-color: rgba(255, 255, 255, 0.12);
}

.accordion-header {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 1.5rem;
  background: var(--bg-card);
  border: none;
  color: var(--fg);
  cursor: pointer;
  font-size: 1.05rem;
  text-align: left;
  transition: background 0.2s;
}

.accordion-header:hover {
  background: var(--bg-card-alt);
}

.accordion-title {
  font-family: var(--serif);
  font-weight: 600;
  letter-spacing: 0.03em;
}

.accordion-icon {
  font-size: 1.3rem;
  color: var(--gold);
  flex-shrink: 0;
  margin-left: 1rem;
  font-weight: 300;
}

.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 1.5rem;
  background: rgba(255, 255, 255, 0.02);
}

.accordion-item.open .accordion-body {
  max-height: 600px;
  padding: 1.5rem;
}

.accordion-body p {
  font-size: 0.95rem;
  color: var(--fg-muted);
  line-height: 1.9;
  margin-bottom: 1rem;
}

.accordion-body p:last-child {
  margin-bottom: 0;
}

/* Diff compare inside accordion */
.diff-compare {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.diff-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.diff-them,
.diff-us {
  padding: 1rem 1.25rem;
  border-radius: 8px;
  font-size: 0.95rem;
  line-height: 1.6;
}

.diff-them {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--fg-muted);
}

.diff-us {
  background: var(--gold-glow);
  border: 1px solid var(--accent-border);
  color: var(--fg);
}

.diff-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  margin-right: 0.5rem;
  background: rgba(255, 255, 255, 0.06);
  color: var(--fg-dim);
  vertical-align: middle;
}

.diff-tag.gold {
  background: rgba(212, 168, 83, 0.2);
  color: var(--gold);
}

/* =========== CTA SECTION =========== */
.cta-section {
  padding: 8rem 0;
  background: linear-gradient(180deg, var(--bg-section) 0%, var(--bg-deep) 100%);
  text-align: center;
}

.cta-content {
  max-width: 600px;
  margin: 0 auto;
}

.cta-title {
  font-family: var(--serif);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 900;
  margin-bottom: 1rem;
  color: var(--gold);
}

.cta-subtitle {
  font-family: var(--serif);
  font-size: 1.1rem;
  color: var(--fg-muted);
  line-height: 1.8;
  margin-bottom: 2.5rem;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.cta-note {
  font-size: 0.85rem;
  color: var(--fg-dim);
}

/* =========== FOOTER =========== */
.site-footer {
  padding: 3rem 0;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  background: var(--bg-deep);
}

.footer-content {
  text-align: center;
}

.footer-brand {
  font-family: var(--serif);
  font-size: 1rem;
  font-weight: 600;
  color: var(--fg-muted);
  margin-bottom: 0.25rem;
}

.footer-tagline {
  font-size: 0.85rem;
  color: var(--fg-dim);
}

/* =========== RESPONSIVE =========== */
@media (max-width: 768px) {
  .landing-nav-links {
    gap: 0.75rem;
  }

  .landing-nav-link {
    font-size: 0.8rem;
  }

  .ideals-grid {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

  .ideal-card {
    padding: 2rem 1.5rem;
  }

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

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

  .diff-row {
    grid-template-columns: 1fr;
  }

  .hero-title {
    font-size: clamp(2.5rem, 10vw, 4rem);
  }

  .ideals,
  .features,
  .pillars-section,
  .philosophy-deep {
    padding: 4rem 0;
  }

  .cta-section {
    padding: 5rem 0;
  }
}

@media (max-width: 480px) {
  .landing-nav-links {
    gap: 0.5rem;
  }

  .landing-nav-link {
    display: none;
  }

  .landing-nav-link:last-of-type {
    display: inline;
  }

  .landing-nav-cta {
    display: inline-block;
  }
}