/* ============================================================
   ShanNan Showcase — Design System
   INFJ 风格：温暖、有深度、不刻板
   ============================================================ */

/* --- CSS Variables --- */
:root {
  --color-primary: #5C4D3C;
  --color-primary-light: #7A6B5A;
  --color-primary-dark: #3E3226;
  --color-accent: #B8845C;
  --color-accent-light: #D4A574;
  --color-highlight: #6B8E6B;
  --color-highlight-light: #8FB88F;

  --color-bg: #FAF8F5;
  --color-bg-alt: #F0EBE5;
  --color-bg-card: #FFFFFF;
  --color-text: #1a1a1a;
  --color-text-secondary: #3a3a3a;
  --color-text-muted: #666666;
  --color-border: #D8D0C8;
  --color-border-light: #E8E0D8;

  --color-paper: #FDFBF7;
  --color-ink: #111111;

  --font-serif: Georgia, 'Noto Serif CJK SC', 'Source Han Serif SC', 'SimSun', serif;
  --font-sans: -apple-system, 'PingFang SC', 'Microsoft YaHei', 'Noto Sans CJK SC', 'Source Han Sans SC', sans-serif;
  --font-mono: 'Courier New', Consolas, monospace;

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);
  --shadow-hover: 0 12px 40px rgba(0,0,0,0.15);

  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  --max-width: 1200px;
  --max-width-reading: 720px;
  --nav-height: 64px;
}

/* --- Reset --- */
*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; font-size:16px; }

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-primary); text-decoration:none; transition:color var(--transition-fast); }
a:hover { color: var(--color-accent); }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-text);
}
h1 { font-size: 2.5rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p { margin-bottom: var(--space-md); color: var(--color-text); }

/* --- Layout --- */
.container { max-width: var(--max-width); margin:0 auto; padding:0 var(--space-xl); }

/* --- Navigation --- */
.nav {
  position:fixed; top:0; left:0; right:0; height:var(--nav-height);
  background: rgba(250,248,245,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: 1000;
}
.nav-inner {
  max-width:var(--max-width); margin:0 auto; padding:0 var(--space-xl);
  height:100%; display:flex; align-items:center; justify-content:space-between;
}
.nav-logo { font-family:var(--font-serif); font-size:1.25rem; font-weight:600; color:var(--color-text); }
.nav-links { display:flex; gap:var(--space-lg); list-style:none; }
.nav-links a {
  font-size:0.9rem; font-weight:500; color:var(--color-text-secondary);
  transition:color var(--transition-fast); position:relative;
}
.nav-links a::after {
  content:''; position:absolute; bottom:-4px; left:0; width:0; height:2px;
  background:var(--color-accent); transition:width var(--transition-base); border-radius:1px;
}
.nav-links a:hover, .nav-links a.active { color:var(--color-text); }
.nav-links a:hover::after, .nav-links a.active::after { width:100%; }

/* --- Cards --- */
.card {
  background:var(--color-bg-card); border-radius:var(--radius-lg);
  border:1px solid var(--color-border-light); padding:var(--space-xl);
  transition:all var(--transition-base);
}
.card:hover { box-shadow:var(--shadow-hover); transform:translateY(-2px); border-color:var(--color-border); }
.card-tag {
  display:inline-block; padding:2px 10px; background:var(--color-bg-alt);
  color:var(--color-text-secondary); border-radius:999px; font-size:0.75rem; font-weight:500;
}

/* --- Buttons --- */
.btn {
  display:inline-flex; align-items:center; gap:var(--space-sm);
  padding:10px 24px; border-radius:var(--radius-md); font-size:0.9rem;
  font-weight:500; font-family:var(--font-sans); cursor:pointer;
  transition:all var(--transition-fast); border:none; outline:none;
}
.btn-primary { background:var(--color-primary); color:#fff; }
.btn-primary:hover { background:var(--color-primary-dark); box-shadow:var(--shadow-md); transform:translateY(-1px); }
.btn-ghost { background:transparent; color:var(--color-text-secondary); border:1px solid var(--color-border); }
.btn-ghost:hover { border-color:var(--color-primary); color:var(--color-primary); }

/* --- Tags --- */
.tag {
  display:inline-flex; align-items:center; gap:4px;
  padding:4px 12px; border-radius:999px; font-size:0.75rem;
  font-weight:500; background:var(--color-bg-alt); color:var(--color-text-secondary);
  transition:all var(--transition-fast);
}
.tag:hover { background:var(--color-border); }

/* --- Hero --- */
.hero { min-height:70vh; display:flex; align-items:center; padding-top:var(--nav-height); }
.hero-content { max-width:640px; }
.hero-greeting { font-size:0.95rem; color:var(--color-accent); font-weight:500; margin-bottom:var(--space-md); letter-spacing:0.05em; }
.hero h1 { font-size:3.2rem; line-height:1.15; margin-bottom:var(--space-lg); letter-spacing:-0.03em; }
.hero h1 .accent { color:var(--color-accent); position:relative; }
.hero h1 .accent::after {
  content:''; position:absolute; bottom:4px; left:0; width:100%; height:8px;
  background:var(--color-accent); opacity:0.15; border-radius:4px; z-index:-1;
}
.hero-desc { font-size:1.1rem; color:var(--color-text-secondary); line-height:1.8; margin-bottom:var(--space-2xl); }
.hero-actions { display:flex; gap:var(--space-md); flex-wrap:wrap; }

/* --- Sections --- */
.section { padding:var(--space-4xl) 0; }
.section-header { margin-bottom:var(--space-3xl); }
.section-header h2 { margin-bottom:var(--space-sm); }
.section-header p { font-size:1rem; color:var(--color-text-secondary); }

/* --- Grid --- */
.grid-2 { display:grid; grid-template-columns:repeat(2,1fr); gap:var(--space-xl); }
.grid-3 { display:grid; grid-template-columns:repeat(3,1fr); gap:var(--space-xl); }

/* --- Divider --- */
.divider { width:40px; height:3px; background:var(--color-accent); border-radius:2px; margin:var(--space-lg) 0; }

/* --- Footer --- */
.footer { padding:var(--space-2xl) 0; border-top:1px solid var(--color-border-light); text-align:center; }
.footer p { font-size:0.85rem; color:var(--color-text-secondary); }

/* --- Scroll Animations --- */
.fade-in { opacity:0; transform:translateY(20px); transition:opacity 0.6s ease, transform 0.6s ease; }
.fade-in.visible { opacity:1; transform:translateY(0); }

/* --- Back to Top --- */
.back-to-top {
  position:fixed; bottom:2rem; right:2rem;
  width:44px; height:44px; border-radius:50%;
  background:var(--color-primary); color:#fff;
  border:none; cursor:pointer; z-index:999;
  display:flex; align-items:center; justify-content:center;
  opacity:0; transform:translateY(20px);
  transition:all var(--transition-base);
  box-shadow:var(--shadow-md);
}
.back-to-top.visible { opacity:1; transform:translateY(0); }
.back-to-top:hover { background:var(--color-accent); box-shadow:var(--shadow-lg); transform:translateY(-2px); }

/* --- Page Transition --- */
.page-loading { position:fixed; top:0; left:0; width:100%; height:100%; background:var(--color-bg); z-index:9999; display:flex; align-items:center; justify-content:center; transition:opacity 0.4s ease; }
.page-loading.fade-out { opacity:0; pointer-events:none; }
.page-loading-spinner {
  width:36px; height:36px; border:3px solid var(--color-border-light);
  border-top-color:var(--color-accent); border-radius:50%;
  animation:spin 0.8s linear infinite;
}
@keyframes spin { to { transform:rotate(360deg); } }

/* --- Responsive --- */
@media (max-width:1024px) { .grid-3 { grid-template-columns:repeat(2,1fr); } }
@media (max-width:768px) {
  :root { --space-xl:1.25rem; --space-2xl:2rem; --space-3xl:2.5rem; --space-4xl:3.5rem; }
  h1 { font-size:2rem; }
  .hero h1 { font-size:2.2rem; }
  .grid-2, .grid-3 { grid-template-columns:1fr; }
  .nav-links { display:none; }
}

@media (prefers-reduced-motion:reduce) {
  * { animation-duration:0.01ms !important; transition-duration:0.01ms !important; }
  .fade-in { opacity:1; transform:none; }
}