/* ================================================================
   图禅 (PhotoZen) — Design System & Component Styles
   ================================================================ */

/* ===== 1. Reset & Base ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--teal); text-decoration: none; transition: opacity var(--duration-fast); }
a:hover { opacity: .85; }
img { max-width: 100%; display: block; }

/* ===== 2. Design Tokens ===== */
:root {
  /* Colors */
  --bg:             #0A0A0C;
  --surface-0:      #0F0F12;
  --surface-1:      #1A1A1F;
  --surface-2:      #232329;
  --surface-3:      #2C2C35;
  --text-primary:   #E1E3E0;
  --text-secondary: #A3A3A3;
  --text-muted:     #525252;
  --teal:           #5EEAD4;
  --teal-dim:       #3CBFAD;
  --teal-dark:      #006B5F;
  --teal-glow:      rgba(94, 234, 212, 0.10);
  --green:          #22C55E;
  --red:            #EF4444;
  --amber:          #FBBF24;
  --blue:           #42A5F5;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 40px;
  --space-2xl: 64px;
  --space-3xl: 100px;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --text-xs:  12px;
  --text-sm:  13px;
  --text-base: 14px;
  --text-md:  16px;
  --text-lg:  18px;
  --text-xl:  24px;
  --text-2xl: 28px;
  --text-3xl: 32px;
  --text-4xl: 36px;
  --text-5xl: 56px;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius:    12px;
  --radius-lg: 16px;
  --radius-xl: 20px;

  /* Borders */
  --border-subtle: rgba(255,255,255,0.04);
  --border-light:  rgba(255,255,255,0.05);
  --border-hover:  rgba(94,234,212,0.15);

  /* Layout */
  --max-w: 1100px;
  --nav-height: 60px;

  /* Transitions */
  --ease-out: cubic-bezier(.16,1,.3,1);
  --duration-fast: 0.15s;
  --duration-mid: 0.3s;
  --duration-slow: 0.7s;
}

/* ===== 3. Utility Classes ===== */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 var(--space-lg); }
.section-pad { padding: var(--space-3xl) 0; }
.text-center { text-align: center; }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }

/* ===== 4. Scroll Animations ===== */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity var(--duration-slow) var(--ease-out), transform var(--duration-slow) var(--ease-out);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 5. Navigation ===== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
  background: rgba(10,10,12,.75);
  border-bottom: 1px solid var(--border-subtle);
  transition: background var(--duration-mid);
}
.navbar--scrolled {
  background: rgba(10,10,12,.92);
}
.navbar-inner {
  max-width: var(--max-w); margin: 0 auto; padding: 0 var(--space-lg);
  height: var(--nav-height); display: flex; align-items: center; justify-content: space-between;
}
.nav-brand { display: flex; align-items: center; gap: 10px; }
.nav-brand svg { width: 32px; height: 32px; border-radius: var(--radius-sm); }
.nav-brand span { font-size: var(--text-lg); font-weight: 700; letter-spacing: .5px; color: var(--text-primary); }
.nav-links { display: flex; gap: 32px; list-style: none; }
.nav-links a {
  color: var(--text-secondary); font-size: var(--text-base); font-weight: 500;
  transition: color .2s;
}
.nav-links a:hover { color: var(--text-primary); opacity: 1; }
.nav-cta {
  display: inline-flex; align-items: center; gap: 6px;
  padding: var(--space-sm) 20px; border-radius: 8px; font-size: var(--text-base); font-weight: 600;
  background: var(--teal); color: #003731;
  transition: transform var(--duration-fast), box-shadow var(--duration-fast);
}
.nav-cta svg { width: 16px; height: 16px; }
.nav-cta:hover { transform: translateY(-1px); box-shadow: 0 4px 20px rgba(94,234,212,.25); opacity: 1; }
.nav-mobile-toggle { display: none; background: none; border: none; color: var(--text-primary); cursor: pointer; padding: var(--space-sm); }

/* Mobile nav dropdown (Alpine.js controlled) */
.nav-links--open {
  display: flex !important; flex-direction: column; position: absolute;
  top: var(--nav-height); left: 0; right: 0; background: rgba(10,10,12,.95);
  padding: var(--space-md) var(--space-lg); gap: var(--space-md);
  border-bottom: 1px solid var(--border-light);
  backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
}

/* ===== 6. Hero Section ===== */
.hero {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  position: relative; overflow: hidden; padding: 80px var(--space-lg) 60px;
}
.hero-glow {
  position: absolute; width: 700px; height: 700px; border-radius: 50%;
  background: radial-gradient(circle, rgba(94,234,212,.09), transparent 70%);
  top: 50%; left: 50%; transform: translate(-50%, -50%);
  pointer-events: none;
}
.hero-glow-2 {
  position: absolute; width: 400px; height: 400px; border-radius: 50%;
  background: radial-gradient(circle, rgba(94,234,212,.05), transparent 70%);
  top: 30%; left: 30%; pointer-events: none;
}
.hero-content { position: relative; text-align: center; max-width: 680px; }
.hero-logo { width: 96px; height: 96px; margin: 0 auto 28px; border-radius: var(--radius-xl); box-shadow: 0 8px 40px rgba(94,234,212,.12); }
.hero-title { font-size: var(--text-5xl); font-weight: 800; letter-spacing: 4px; margin-bottom: var(--space-md); }
.hero-tagline {
  font-size: var(--text-xl); font-weight: 500; color: var(--text-secondary);
  margin-bottom: var(--space-sm);
}
.hero-version {
  font-size: var(--text-sm); color: var(--text-muted); margin-bottom: var(--space-md);
}
.hero-sub {
  display: flex; justify-content: center; gap: var(--space-lg); flex-wrap: wrap;
  margin-bottom: var(--space-xl);
}
.hero-sub span {
  font-size: var(--text-base); color: var(--text-muted); letter-spacing: 1px;
}
.hero-sub span::before {
  content: ''; display: inline-block; width: 6px; height: 6px; border-radius: 50%;
  background: var(--teal); margin-right: var(--space-sm); vertical-align: middle; opacity: .6;
}
.hero-cta {
  display: inline-flex; align-items: center; gap: var(--space-sm);
  padding: 14px 36px; border-radius: var(--radius-md); font-size: var(--text-md); font-weight: 700;
  background: var(--teal); color: #003731;
  transition: transform var(--duration-fast), box-shadow .2s;
}
.hero-cta:hover { transform: translateY(-2px); box-shadow: 0 6px 30px rgba(94,234,212,.3); opacity: 1; }
.hero-cta svg { width: 18px; height: 18px; }
.hero-scroll-hint {
  position: absolute; bottom: 32px; left: 50%; transform: translateX(-50%);
  color: var(--text-muted); font-size: var(--text-sm);
  animation: float 2.5s ease-in-out infinite;
}
@keyframes float {
  0%,100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ===== 7. Problems Section ===== */
.problems { background: var(--surface-0); }
.problems-title { font-size: var(--text-2xl); font-weight: 700; margin-bottom: 48px; }
.problems-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-lg); }
.problem-card {
  padding: 32px var(--space-lg); border-radius: var(--radius);
  background: var(--surface-1); border: 1px solid var(--border-subtle);
  transition: border-color var(--duration-mid), transform var(--duration-mid);
}
.problem-card:hover { border-color: var(--border-hover); transform: translateY(-2px); }
.problem-icon {
  width: 48px; height: 48px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: var(--space-md); font-size: 22px;
}
.problem-card h3 { font-size: var(--text-lg); font-weight: 600; margin-bottom: var(--space-sm); }
.problem-card p { font-size: var(--text-base); color: var(--text-secondary); line-height: 1.6; }

/* ===== 8. Feature Sections ===== */
.feature {
  padding: var(--space-3xl) 0;
  border-bottom: 1px solid rgba(255,255,255,.03);
}
.feature:last-child { border-bottom: none; }
.feature-inner {
  max-width: var(--max-w); margin: 0 auto; padding: 0 var(--space-lg);
  display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center;
}
.feature:nth-child(even) .feature-inner { direction: rtl; }
.feature:nth-child(even) .feature-inner > * { direction: ltr; }
.feature-tag {
  display: inline-block; font-size: var(--text-xs); font-weight: 600; letter-spacing: 1.5px;
  text-transform: uppercase; margin-bottom: var(--space-sm); padding: var(--space-xs) var(--space-sm);
  border-radius: 4px; background: rgba(94,234,212,.1); color: var(--teal);
}
.feature-title { font-size: var(--text-3xl); font-weight: 700; margin-bottom: var(--space-md); line-height: 1.3; }
.feature-desc { font-size: var(--text-md); color: var(--text-secondary); line-height: 1.8; margin-bottom: 20px; }
.feature-highlights { list-style: none; display: flex; flex-wrap: wrap; gap: var(--space-md); }
.feature-highlights li {
  font-size: var(--text-sm); padding: 6px 14px; border-radius: var(--radius-sm);
  background: var(--surface-1); color: var(--text-secondary);
  border: 1px solid var(--border-light);
}

/* Feature Visual Cards */
.feature-visual {
  display: flex; align-items: center; justify-content: center;
  aspect-ratio: 4/3; border-radius: var(--radius-lg);
  background: var(--surface-1); border: 1px solid var(--border-light);
  position: relative; overflow: hidden;
}
.feature-visual::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(ellipse at center, var(--teal-glow), transparent 70%);
  opacity: .5;
}
.feature-visual svg { position: relative; z-index: 1; }

/* FlowSorter visual */
.vis-flow svg { width: 65%; }
/* Analysis visual */
.vis-analysis svg { width: 55%; }
.vis-analysis::before { background: radial-gradient(ellipse at center, rgba(94,234,212,.08), transparent 70%); }
/* LightTable visual */
.vis-lighttable svg { width: 70%; }
/* Achievement visual */
.vis-achievement svg { width: 50%; }
.vis-achievement::before { background: radial-gradient(ellipse at center, rgba(251,191,36,.06), transparent 70%); }
/* Widget visual */
.vis-widget svg { width: 45%; }

/* ===== 9. Principles Section ===== */
.principles { background: var(--surface-0); }
.principles-title { font-size: var(--text-2xl); font-weight: 700; margin-bottom: 48px; }
.principles-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-lg); }
.principle-item { text-align: center; padding: 28px var(--space-md); }
.principle-icon {
  width: 52px; height: 52px; border-radius: var(--radius); margin: 0 auto var(--space-md);
  display: flex; align-items: center; justify-content: center;
  background: var(--surface-2); border: 1px solid var(--border-light);
}
.principle-icon svg { width: 24px; height: 24px; }
.principle-item h3 { font-size: var(--text-md); font-weight: 600; margin-bottom: var(--space-sm); }
.principle-item p { font-size: var(--text-sm); color: var(--text-secondary); line-height: 1.6; }

/* ===== 10. Download Section ===== */
.download { position: relative; overflow: hidden; }
.download-glow {
  position: absolute; width: 600px; height: 600px; border-radius: 50%;
  background: radial-gradient(circle, rgba(94,234,212,.07), transparent 70%);
  top: 50%; left: 50%; transform: translate(-50%, -50%); pointer-events: none;
}
.download-content { position: relative; }
.download-title { font-size: var(--text-4xl); font-weight: 800; margin-bottom: var(--space-md); }
.download-sub { font-size: var(--text-md); color: var(--text-secondary); margin-bottom: var(--space-xl); }
.download-cta {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 16px 44px; border-radius: var(--radius); font-size: var(--text-lg); font-weight: 700;
  background: var(--teal); color: #003731;
  transition: transform var(--duration-fast), box-shadow .2s;
}
.download-cta:hover { transform: translateY(-2px); box-shadow: 0 8px 40px rgba(94,234,212,.3); opacity: 1; }
.download-cta svg { width: 20px; height: 20px; }
.download-note {
  margin-top: 20px; font-size: var(--text-sm); color: var(--text-muted);
}
.download-badges {
  margin-top: 32px; display: flex; justify-content: center; gap: 28px; flex-wrap: wrap;
}
.download-badge {
  font-size: var(--text-base); color: var(--text-secondary);
  display: flex; align-items: center; gap: var(--space-sm);
}
.download-badge svg { width: 18px; height: 18px; color: var(--teal); }

/* ===== 11. Feedback Section ===== */
.feedback { background: var(--surface-0); }
.feedback-title { font-size: var(--text-2xl); font-weight: 700; margin-bottom: var(--space-sm); }
.feedback-sub { font-size: var(--text-md); color: var(--text-secondary); margin-bottom: var(--space-xl); }
.feedback-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-lg); max-width: 680px; margin: 0 auto; }
.feedback-card {
  padding: 28px var(--space-lg); border-radius: var(--radius);
  background: var(--surface-1); border: 1px solid var(--border-subtle);
  text-align: center;
}
.feedback-card-icon {
  width: 44px; height: 44px; border-radius: var(--radius-md); margin: 0 auto 14px;
  display: flex; align-items: center; justify-content: center;
  background: var(--surface-2);
}
.feedback-card-icon svg { width: 22px; height: 22px; color: var(--teal); }
.feedback-card h3 { font-size: var(--text-md); font-weight: 600; margin-bottom: 6px; }
.feedback-card p { font-size: var(--text-base); color: var(--text-secondary); line-height: 1.6; }

/* ===== 12. Footer ===== */
.footer {
  padding: 32px var(--space-lg); text-align: center;
  border-top: 1px solid var(--border-subtle);
  font-size: var(--text-sm); color: var(--text-muted);
}
.footer a { color: var(--text-muted); }
.footer a:hover { color: var(--text-secondary); }

/* ===== 13. Prose Pages (Privacy / Changelog) ===== */
.prose-page { padding-top: calc(var(--nav-height) + 40px); padding-bottom: var(--space-3xl); }
.prose { max-width: 720px; margin: 0 auto; padding: 0 var(--space-lg); }
.prose h1 { font-size: var(--text-3xl); margin-bottom: var(--space-lg); }
.prose h2 { font-size: var(--text-xl); margin-top: var(--space-2xl); margin-bottom: var(--space-md); color: var(--teal); }
.prose h3 { font-size: var(--text-lg); margin-top: var(--space-xl); margin-bottom: var(--space-sm); }
.prose p  { margin-bottom: var(--space-md); color: var(--text-secondary); line-height: 1.8; }
.prose ul, .prose ol { padding-left: var(--space-lg); margin-bottom: var(--space-md); color: var(--text-secondary); }
.prose li { line-height: 1.8; margin-bottom: var(--space-xs); }
.prose a  { color: var(--teal); text-decoration: underline; text-underline-offset: 3px; }
.prose strong { color: var(--text-primary); }
.prose .meta { font-size: var(--text-sm); color: var(--text-muted); margin-bottom: var(--space-xl); }
.prose .version-badge {
  display: inline-block; padding: var(--space-xs) var(--space-md);
  background: var(--teal-glow); color: var(--teal); border-radius: var(--radius-sm);
  font-size: var(--text-sm); font-weight: 600; margin-bottom: var(--space-lg);
}
.prose pre {
  background: var(--surface-1); border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm); padding: var(--space-md);
  overflow-x: auto; margin-bottom: var(--space-md);
  font-size: var(--text-sm); color: var(--text-secondary); white-space: pre-wrap;
}

/* ===== 14. Responsive — Tablet (max-width: 900px) ===== */
@media (max-width: 900px) {
  .problems-grid { grid-template-columns: 1fr; gap: var(--space-md); }
  .feature-inner { grid-template-columns: 1fr !important; gap: 32px; }
  .feature:nth-child(even) .feature-inner { direction: ltr; }
  .feature-visual { aspect-ratio: 16/10; }
  .principles-grid { grid-template-columns: repeat(2, 1fr); gap: var(--space-md); }
  .feedback-grid { grid-template-columns: 1fr; }
}

/* ===== 15. Responsive — Mobile (max-width: 640px) ===== */
@media (max-width: 640px) {
  .hero-title { font-size: var(--text-4xl); letter-spacing: 2px; }
  .hero-tagline { font-size: var(--text-lg); }
  .hero-logo { width: 72px; height: 72px; border-radius: var(--radius-lg); }
  .hero-sub { gap: var(--space-md); }
  .feature { padding: var(--space-2xl) 0; }
  .feature-title { font-size: var(--text-xl); }
  .section-pad { padding: var(--space-2xl) 0; }
  .problems-title, .principles-title, .feedback-title { font-size: 22px; }
  .download-title { font-size: var(--text-2xl); }
  .nav-links { display: none; }
  .nav-mobile-toggle { display: block; }
  .principles-grid { grid-template-columns: 1fr 1fr; }
  .prose h1 { font-size: var(--text-xl); }
  .prose h2 { font-size: var(--text-lg); }
}

/* ===== 16. Responsive — Large Screen (min-width: 1440px) ===== */
@media (min-width: 1440px) {
  :root { --max-w: 1200px; }
  .hero-title { font-size: 64px; }
}