/* =========================================================
   刘星辰 · Portfolio — 共享样式表
   包含：CSS 变量、重置、导航、按钮、页脚、主题切换、
   滚动条、回到顶部、显示动画、响应式断点
   适用于：index.html / works.html / about.html / contact.html /
           work-detail.html / 404.html
   ========================================================= */

/* ── CSS Reset ── */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

/* ── CSS 变量 (暗色主题为默认) ── */
:root{
  color-scheme:dark light;
  --bg-deep:#0d0b09;--bg-base:#141210;--bg-surface:#1b1815;--bg-elevated:#221f1b;
  --ink:#f2efe8;--ink-soft:#d4cfc7;--muted:#a39e97;--muted-2:#6b6760;
  --line:rgba(242,239,232,0.07);--line-strong:rgba(242,239,232,0.14);
  --accent:#c9a96e;--accent-dim:rgba(201,169,110,0.13);--accent-glow:rgba(201,169,110,0.3);
  --accent-rose:rgba(196,160,160,0.12);
  --r-xl:20px;--r-lg:14px;--r-md:10px;--r-sm:6px;
  --max:1120px;--pad-x:24px;
  --sp-2xs:4px;--sp-xs:8px;--sp-sm:12px;--sp-md:16px;--sp-lg:24px;--sp-xl:32px;
  --sp-2xl:40px;--sp-3xl:48px;--sp-4xl:64px;--sp-5xl:80px;--sp-6xl:96px;--sp-7xl:120px;
  --font-display:"Cormorant Garamond","Georgia","Times New Roman","STSong","SimSun",serif;
  --font-body:"DM Sans","PingFang SC","Microsoft YaHei","Helvetica Neue","Arial",sans-serif;
  --font-mono:"JetBrains Mono","SF Mono","Menlo","Consolas",monospace;
  --font-zh:"Noto Serif SC","STSong","SimSun","Georgia",serif;
  --ease-out:cubic-bezier(0.22,0.61,0.36,1);
  --ease-spring:cubic-bezier(0.34,1.56,0.64,1);
}

/* ── 亮色主题 — 系统偏好 ── */
@media(prefers-color-scheme:light){
  :root{
    --bg-deep:#faf8f4;--bg-base:#f5f2ec;--bg-surface:#ede8e0;--bg-elevated:#e3ddd4;
    --ink:#1a1612;--ink-soft:#3d3831;--muted:#6b6560;--muted-2:#8f8983;
    --line:rgba(26,22,18,0.06);--line-strong:rgba(26,22,18,0.1);
    --accent:#a87d3a;--accent-dim:rgba(168,125,58,0.1);--accent-glow:rgba(168,125,58,0.2);
    --accent-rose:rgba(160,120,120,0.08);
  }
  body{background:linear-gradient(180deg,#faf8f4 0%,#f5f2ec 40%,#faf8f4 100%)}
  .site-header.is-scrolled{background:rgba(250,248,244,.82)}
  .brand-mark{background:linear-gradient(135deg,#e8e2d8,#d5cec2);border-color:rgba(168,125,58,0.28)}
  .nav-links a.is-active{background:rgba(26,22,18,0.04)}
  .nav-cta{border-color:rgba(168,125,58,0.28);background:rgba(168,125,58,0.06)}
  .nav-cta:hover{background:rgba(168,125,58,0.12);border-color:rgba(168,125,58,0.4)}
  .button-primary{color:#faf8f4;background:linear-gradient(135deg,#1a1612,#3d3831);border-color:rgba(168,125,58,0.35);box-shadow:0 8px 28px rgba(168,125,58,0.08)}
  .button-primary:hover{background:linear-gradient(135deg,#2a2520,#4d4840);box-shadow:0 14px 36px rgba(168,125,58,0.18)}
  .button-ghost{color:var(--ink-soft);background:rgba(26,22,18,0.02);border-color:var(--line-strong)}
  .button-ghost:hover{color:var(--ink);background:rgba(26,22,18,0.05);border-color:rgba(168,125,58,0.25)}
  .btt-btn{background:rgba(245,242,236,.85);border-color:rgba(168,125,58,0.35)}
  .btt-btn:hover{background:rgba(235,230,222,.92);border-color:rgba(168,125,58,0.55)}
  .footer-social a{border-color:rgba(26,22,18,0.12)}
  .footer-social a:hover{border-color:rgba(168,125,58,0.3)}
  .scroll-bar span{box-shadow:0 0 8px rgba(168,125,58,0.3)}
  .section-divider{background:linear-gradient(90deg,transparent,rgba(26,22,18,0.06) 20%,rgba(26,22,18,0.06) 80%,transparent);opacity:.8}
}

/* ── 亮色主题 — 手动切换 data-theme="light" ── */
html[data-theme="light"]{
  --bg-deep:#faf8f4;--bg-base:#f5f2ec;--bg-surface:#ede8e0;--bg-elevated:#e3ddd4;
  --ink:#1a1612;--ink-soft:#3d3831;--muted:#6b6560;--muted-2:#8f8983;
  --line:rgba(26,22,18,0.06);--line-strong:rgba(26,22,18,0.1);
  --accent:#a87d3a;--accent-dim:rgba(168,125,58,0.1);--accent-glow:rgba(168,125,58,0.2);
  --accent-rose:rgba(160,120,120,0.08);
}
html[data-theme="light"] body{background:linear-gradient(180deg,#faf8f4 0%,#f5f2ec 40%,#faf8f4 100%)}
html[data-theme="light"] .site-header.is-scrolled{background:rgba(250,248,244,.82)}
html[data-theme="light"] .brand-mark{background:linear-gradient(135deg,#e8e2d8,#d5cec2);border-color:rgba(168,125,58,0.28)}
html[data-theme="light"] .nav-links a.is-active{background:rgba(26,22,18,0.04)}
html[data-theme="light"] .nav-cta{border-color:rgba(168,125,58,0.28);background:rgba(168,125,58,0.06)}
html[data-theme="light"] .nav-cta:hover{background:rgba(168,125,58,0.12);border-color:rgba(168,125,58,0.4)}
html[data-theme="light"] .button-primary{color:#faf8f4;background:linear-gradient(135deg,#1a1612,#3d3831);border-color:rgba(168,125,58,0.35);box-shadow:0 8px 28px rgba(168,125,58,0.08)}
html[data-theme="light"] .button-primary:hover{background:linear-gradient(135deg,#2a2520,#4d4840);box-shadow:0 14px 36px rgba(168,125,58,0.18)}
html[data-theme="light"] .button-ghost{color:var(--ink-soft);background:rgba(26,22,18,0.02);border-color:var(--line-strong)}
html[data-theme="light"] .button-ghost:hover{color:var(--ink);background:rgba(26,22,18,0.05);border-color:rgba(168,125,58,0.25)}
html[data-theme="light"] .btt-btn{background:rgba(245,242,236,.85);border-color:rgba(168,125,58,0.35)}
html[data-theme="light"] .btt-btn:hover{background:rgba(235,230,222,.92);border-color:rgba(168,125,58,0.55)}
html[data-theme="light"] .footer-social a{border-color:rgba(26,22,18,0.12)}
html[data-theme="light"] .footer-social a:hover{border-color:rgba(168,125,58,0.3)}
html[data-theme="light"] .scroll-bar span{box-shadow:0 0 8px rgba(168,125,58,0.3)}
html[data-theme="light"] .section-divider{background:linear-gradient(90deg,transparent,rgba(26,22,18,0.06) 20%,rgba(26,22,18,0.06) 80%,transparent);opacity:.8}

/* ── 暗色主题 — 手动切换 data-theme="dark" ── */
html[data-theme="dark"]{
  --bg-deep:#0d0b09;--bg-base:#12100e;--bg-surface:#1a1816;--bg-elevated:#22201d;
  --ink:#f2efe8;--ink-soft:#c8c4bc;--muted:#8f8983;--muted-2:#5e5a55;
  --line:rgba(242,239,232,0.06);--line-strong:rgba(242,239,232,0.1);
  --accent:#c9a96e;--accent-dim:rgba(201,169,110,0.1);--accent-glow:rgba(201,169,110,0.2);
  --accent-rose:rgba(196,160,160,0.08);
}
html[data-theme="dark"] body{background:linear-gradient(180deg,#0d0b09 0%,#12100e 40%,#0d0b09 100%)}

/* ── 基础样式 ── */
html{scroll-behavior:smooth;scrollbar-width:thin;scrollbar-color:rgba(242,239,232,0.1) transparent;background:var(--bg-deep)}
html,body{min-height:100vh;overflow-x:hidden}
body{
  font-family:var(--font-body);font-weight:400;color:var(--ink-soft);line-height:1.75;font-size:16px;
  letter-spacing:0.01em;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;
  background:radial-gradient(900px 400px at 80% -10%,rgba(201,169,110,0.05),transparent 60%),
             radial-gradient(700px 350px at -5% 25%,rgba(196,160,160,0.04),transparent 65%),
             radial-gradient(800px 500px at 50% 80%,rgba(201,169,110,0.03),transparent 60%),
             linear-gradient(180deg,#0d0b09 0%,#141210 40%,#0d0b09 100%);
}
a{color:inherit;text-decoration:none}
::selection{background:var(--accent-dim);color:var(--ink)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:3px}

/* ── 通用布局 ── */
.section-shell{width:min(calc(100% - var(--pad-x)*2),var(--max));margin:0 auto}
.section-divider{width:100%;max-width:var(--max);margin:0 auto;height:1px;background:linear-gradient(90deg,transparent,var(--line-strong) 20%,var(--line-strong) 80%,transparent);opacity:.6}

/* ── Header ── */
.site-header{position:fixed;top:0;left:0;right:0;z-index:40;padding:18px 0;transition:padding .4s var(--ease-out),background .4s var(--ease-out)}
.site-header.is-scrolled{padding:10px 0;background:rgba(13,11,9,.82);backdrop-filter:blur(20px) saturate(120%);-webkit-backdrop-filter:blur(20px) saturate(120%);border-bottom:1px solid var(--line)}
.header-inner{width:min(calc(100% - var(--pad-x)*2),var(--max));margin:0 auto;display:flex;align-items:center;justify-content:space-between;gap:20px;min-height:44px}

/* ── Brand ── */
.brand{display:flex;align-items:center;gap:12px;font-family:var(--font-display);font-weight:600;font-size:17px;letter-spacing:-0.01em;color:var(--ink)}
.brand-mark{display:grid;place-items:center;width:34px;height:34px;border-radius:9px;flex-shrink:0;background:linear-gradient(135deg,#2a2520,#1c1814);border:1px solid rgba(201,169,110,0.22);font-family:var(--font-mono);font-size:11px;color:var(--accent);font-weight:500}
.brand-sub{font-size:11px;color:var(--muted);font-family:var(--font-mono);letter-spacing:0.06em;font-weight:400}

/* ── 桌面导航 ── */
.nav-links{display:flex;align-items:center;gap:2px;position:relative}
.nav-links a{position:relative;padding:8px 15px;border-radius:7px;font-size:13px;font-weight:500;color:var(--muted);transition:color .28s var(--ease-out),background .28s var(--ease-out);min-height:36px;display:flex;align-items:center}
.nav-links a:hover,.nav-links a.is-active{color:var(--ink)}
.nav-links a.is-active{background:rgba(242,239,232,0.05)}
.nav-links a .nav-num{font-family:var(--font-mono);font-size:10px;color:var(--accent);margin-right:6px;letter-spacing:0.06em;opacity:.7}

/* ── 导航指示器 ── */
.nav-indicator{position:absolute;bottom:-1px;left:0;height:2px;background:linear-gradient(90deg,transparent,var(--accent),transparent);border-radius:1px;pointer-events:none;transition:left .4s var(--ease-out),width .4s var(--ease-out),opacity .3s var(--ease-out);opacity:0}

/* ── CTA 按钮 ── */
.nav-cta{display:inline-flex;align-items:center;gap:8px;padding:9px 16px 9px 14px;border-radius:9px;min-height:40px;border:1px solid rgba(201,169,110,0.28);background:rgba(201,169,110,0.07);color:var(--ink);font-size:13px;font-weight:500;transition:background .3s var(--ease-out),border-color .3s var(--ease-out),transform .3s var(--ease-out)}
.nav-cta:hover{background:rgba(201,169,110,0.14);border-color:rgba(201,169,110,0.45);transform:translateY(-1px)}
.nav-cta .dot{width:6px;height:6px;border-radius:50%;background:#8aff9c;box-shadow:0 0 10px rgba(138,255,156,0.55);animation:pulse 2.4s ease-in-out infinite}
@keyframes pulse{50%{transform:scale(1.5);opacity:.5}}

/* ── 主题切换 ── */
.theme-toggle{width:38px;height:38px;border-radius:50%;border:1px solid var(--line-strong);background:transparent;color:var(--muted);cursor:pointer;display:flex;align-items:center;justify-content:center;transition:color .3s var(--ease-out),border-color .3s var(--ease-out),transform .3s var(--ease-spring);flex-shrink:0}
.theme-toggle:hover{color:var(--accent);border-color:rgba(201,169,110,0.35);transform:rotate(30deg)}
.theme-toggle svg{width:16px;height:16px}
.theme-toggle .icon-sun{display:none}
html[data-theme="light"] .theme-toggle .icon-sun{display:block}
html[data-theme="light"] .theme-toggle .icon-moon{display:none}

/* ── 汉堡菜单 ── */
.hamburger{display:none;position:relative;z-index:50;width:44px;height:44px;border:0;background:transparent;cursor:pointer;flex-shrink:0;align-items:center;justify-content:center}
.hamburger span{display:block;width:22px;height:1.5px;background:var(--ink);border-radius:1px;transition:transform .35s var(--ease-out),opacity .35s var(--ease-out);position:relative}
.hamburger span::before,.hamburger span::after{content:"";position:absolute;left:0;width:100%;height:1.5px;background:var(--ink);border-radius:1px;transition:transform .35s var(--ease-out),top .35s var(--ease-out)}
.hamburger span::before{top:-7px}
.hamburger span::after{top:7px}
.hamburger.is-open span{background:transparent}
.hamburger.is-open span::before{top:0;transform:rotate(45deg)}
.hamburger.is-open span::after{top:0;transform:rotate(-45deg)}

/* ── 移动端导航 ── */
.mobile-nav{position:fixed;inset:0;z-index:45;background:rgba(13,11,9,.96);backdrop-filter:blur(24px);-webkit-backdrop-filter:blur(24px);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;opacity:0;pointer-events:none;transition:opacity .4s var(--ease-out)}
.mobile-nav.is-open{opacity:1;pointer-events:auto}
.mobile-nav a{font-family:var(--font-display);font-size:clamp(28px,5vw,42px);font-style:italic;color:var(--ink);padding:12px 24px;transition:color .3s var(--ease-out),transform .3s var(--ease-out)}
.mobile-nav a:hover{color:var(--accent);transform:translateX(6px)}
.mobile-nav .mn-num{font-family:var(--font-mono);font-size:11px;color:var(--accent);margin-right:10px;font-style:normal;letter-spacing:0.12em}

/* ── 滚动进度条 ── */
.scroll-bar{position:fixed;top:0;left:0;right:0;height:1px;z-index:50;background:transparent}
.scroll-bar span{display:block;height:100%;width:0;background:linear-gradient(90deg,transparent,var(--accent) 60%,var(--accent-rose));box-shadow:0 0 8px rgba(201,169,110,0.5);transition:width 120ms linear}

/* ── 显示动画 ── */
[data-reveal]{opacity:0;transform:translateY(22px);transition:opacity .9s var(--ease-out),transform .9s var(--ease-out)}
[data-reveal].is-visible{opacity:1;transform:none}

/* ── 回到顶部按钮 ── */
.btt-btn{position:fixed;right:24px;bottom:80px;z-index:45;width:44px;height:44px;border-radius:50%;border:1px solid rgba(201,169,110,0.35);background:rgba(20,18,16,.85);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);color:var(--accent);display:flex;align-items:center;justify-content:center;cursor:pointer;opacity:0;transform:translateY(12px);pointer-events:none;transition:opacity .35s var(--ease-out),transform .35s var(--ease-out),background .3s var(--ease-out),border-color .3s var(--ease-out),box-shadow .35s var(--ease-out)}
.btt-btn.is-visible{opacity:1;transform:translateY(0);pointer-events:auto}
.btt-btn:hover{background:rgba(30,28,24,.92);border-color:rgba(201,169,110,0.55);transform:translateY(-3px);box-shadow:0 0 24px rgba(201,169,110,0.15)}
.btt-btn svg{width:18px;height:18px}

/* ── 按钮 ── */
.button{position:relative;display:inline-flex;align-items:center;gap:10px;height:46px;padding:0 20px;border-radius:11px;font-size:14px;font-weight:500;letter-spacing:0.01em;transition:transform .3s var(--ease-spring),background .3s var(--ease-out),color .3s var(--ease-out),border-color .3s var(--ease-out),box-shadow .3s var(--ease-out);cursor:pointer;min-width:44px;overflow:hidden;isolation:isolate}
.button svg{width:16px;height:16px;transition:transform .3s var(--ease-out);flex-shrink:0;position:relative;z-index:1}
.button:hover svg{transform:translateX(4px)}
.button span{position:relative;z-index:1}
.button-primary{color:#141210;background:linear-gradient(135deg,#f2efe8,#d6ccb5);border:1px solid rgba(201,169,110,0.35);box-shadow:0 8px 28px rgba(201,169,110,0.12)}
.button-primary:hover{transform:translateY(-2px);background:linear-gradient(135deg,#f7f5f0,#e2d9c5);box-shadow:0 14px 36px rgba(201,169,110,0.24)}
.button-ghost{color:var(--ink-soft);background:rgba(242,239,232,0.03);border:1px solid var(--line-strong)}
.button-ghost:hover{color:var(--ink);background:rgba(242,239,232,0.07);border-color:rgba(201,169,110,0.25);transform:translateY(-2px)}
.button::before{content:"";position:absolute;inset:0;border-radius:inherit;background:linear-gradient(105deg,transparent 40%,rgba(255,255,255,0.06) 45%,rgba(255,255,255,0.1) 50%,rgba(255,255,255,0.06) 55%,transparent 60%);transform:translateX(-100%);transition:transform .6s var(--ease-out);pointer-events:none;z-index:0}
.button:hover::before{transform:translateX(100%)}

/* ── 页脚 ── */
.footer{padding:56px 0 36px;border-top:1px solid var(--line);margin-top:var(--sp-5xl)}
.footer-inner{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px}
.footer-brand{display:flex;align-items:center;gap:12px}
.footer-brand strong{display:block;font-family:var(--font-display);font-weight:500;letter-spacing:-0.01em;color:var(--ink);font-style:italic}
.footer-brand span{font-size:12px;color:var(--muted)}
.footer-meta{display:flex;gap:20px;font-family:var(--font-mono);font-size:10.5px;letter-spacing:0.06em;color:var(--muted)}
.footer-social{display:flex;flex-direction:row;gap:4px;list-style:none;padding:0;margin:0}
.footer-social a{display:flex;align-items:center;justify-content:center;width:38px;height:38px;border-radius:50%;border:1px solid var(--line-strong);color:var(--muted);transition:color .3s var(--ease-out),border-color .3s var(--ease-out),transform .3s var(--ease-spring)}
.footer-social a:hover{color:var(--accent);border-color:rgba(201,169,110,0.35);transform:translateY(-2px)}
.footer-social a svg{width:16px;height:16px;display:block}
.footer-quote{text-align:center;font-style:italic;font-size:12px;color:var(--muted);padding:14px 0 0;margin:0;transition:opacity .5s var(--ease-out);opacity:1;font-family:var(--font-display)}

/* ── 响应式 — 880px ── */
@media(max-width:880px){
  .nav-links,.nav-cta,.theme-toggle{display:none}
  .hamburger{display:flex}
  .site-header{padding:10px 0}
  .footer-inner{flex-direction:column;align-items:flex-start}
  .footer-social{flex-wrap:wrap}
}

/* ── 响应式 — 640px ── */
@media(max-width:640px){
  .brand-sub{display:none}
  .btt-btn{right:16px;bottom:80px}
  .footer-inner{flex-direction:column;align-items:flex-start}
  .footer-quote{font-size:10.5px;padding:10px 0 0}
  .button{width:100%;justify-content:center;height:48px}
}

/* ── 响应式 — 560px ── */
@media(max-width:560px){
  .brand-sub{display:none}
  .btt-btn{right:16px;bottom:80px}
}

/* ── 高对比度偏好 ── */
@media(prefers-contrast:high){
  :root{
    --line:rgba(242,239,232,0.18);--line-strong:rgba(242,239,232,0.28);
    --muted:#b8b2a8;--muted-2:#8a847c;
  }
  [data-theme="light"]{--line:rgba(26,22,18,0.14);--line-strong:rgba(26,22,18,0.22);--muted:#4a4440;--muted-2:#6b6560}
  a{text-decoration:underline;text-underline-offset:3px}
  .button{border-width:2px}
  :focus-visible{outline-width:3px}
}

/* ── 减少透明度偏好 ── */
@media(prefers-reduced-transparency:reduce){
  .site-header.is-scrolled{backdrop-filter:none;-webkit-backdrop-filter:none}
  .site-header.is-scrolled{background:var(--bg-deep)}
  .btt-btn{backdrop-filter:none;-webkit-backdrop-filter:none}
  .bg-glow,.glow-top,.glow-bot{opacity:.08!important}
}

/* ── 减少动画偏好 ── */
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:0.01ms!important;animation-iteration-count:1!important;transition-duration:0.01ms!important;scroll-behavior:auto!important}
  [data-reveal]{opacity:1;transform:none;transition:none}
  .marquee{animation:none!important}
  .nav-indicator{transition:none!important}
}

/* ── 打印样式 ── */
@media print{
  html,body{background:#fff!important;color:#000!important;font-size:11pt}
  .site-header,.scroll-bar,.btt-btn,.mobile-nav,.hamburger,.theme-toggle,
  .bg-grain,.bg-dots,.bg-glow,.glow-top,.glow-bot,.nav-cta,.nav-indicator,
  .mobile-bottom-nav,.chapter-dots,.marquee,.footer-social,
  #heroParticles,#backToTop{display:none!important}
  .section-shell{max-width:100%;width:100%}
  .footer{border-top:1px solid #ccc}
  .footer-inner{flex-direction:row}
  a{color:#000;text-decoration:underline}
  .button,.button-primary,.button-ghost{background:#fff!important;color:#000!important;border:1px solid #000!important;box-shadow:none!important}
  .work-card,.principle-card,.strength-card,.contact-card,.cta-panel{box-shadow:none!important;border:1px solid #ccc!important;break-inside:avoid}
  .work-thumb{height:120px}
  .work-grid{grid-template-columns:repeat(2,1fr)}
  .page-hero,.page-title-section{padding:20px 0}
  .page-title,.page-hero-title{font-size:28pt!important}
  @page{margin:1.5cm}
}

/* ── 移动端触屏优化 ── */
@media(hover:none) and (pointer:coarse){
  .work-card:hover,.principle-card:hover,.strength-card:hover,.contact-card:hover{transform:none;box-shadow:none}
  .work-card:active,.principle-card:active,.strength-card:active,.contact-card:active{transform:scale(0.98);transition:transform .15s var(--ease-out)}
  .btt-btn{right:12px;bottom:70px}
  input,textarea,select,button{font-size:16px}
}

/* ── GPU 加速与性能 ── */
@media(prefers-reduced-motion:no-preference){
  .site-header{will-change:transform}
  .scroll-bar span{will-change:width}
  .work-card{will-change:transform,opacity}
  [data-reveal]{will-change:transform,opacity;content-visibility:auto;contain-intrinsic-size:auto 200px}
  [data-reveal].is-visible{content-visibility:visible;contain-intrinsic-size:none}
}