/* ════════════════════════════════════════════
   YAI 全站共用 design system
   ════════════════════════════════════════════ */

/* ── Variables ── */
:root,[data-theme="light"]{
  --bg:#ffffff;--card:#ffffff;--ink:#0f1a2e;--ink2:#3a4a62;--ink3:#8a96a8;
  --accent:#5B4FE8;--border:#e8ebf2;--surface:#f5f6fa;--pill:rgba(255,255,255,.88);
  --nav-bg:rgba(255,255,255,.92);
  --amber:#d97706;--red:#dc2626;
}
[data-theme="dark"]{
  --bg:#161616;--card:#1d1d1d;--ink:#f4f4f5;--ink2:#c8d0dc;--ink3:#8a94a6;
  --accent:#a5b4fc;--border:#2c2c2c;--surface:#222222;--pill:rgba(30,30,30,.88);
  --nav-bg:rgba(22,22,22,.92);
  --amber:#fbbf24;--red:#f87171;
}

/* ── Base ── */
*{box-sizing:border-box;margin:0;padding:0}
body{background:var(--bg);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang HK","PingFang TC","Microsoft JhengHei",sans-serif;line-height:1.7;transition:background .2s,color .2s}
a{text-decoration:none;color:inherit}
img{display:block;max-width:100%}
.wrap{max-width:600px;margin:0 auto;padding:0 18px}

/* ── Topbar ── */
.topbar{display:flex;align-items:center;justify-content:space-between;padding:16px 0 8px}
.topbar-logo{display:block;width:38px;height:38px;border-radius:10px;overflow:hidden}
.topbar-logo img{width:100%;height:100%;object-fit:cover}
.topbar-right{display:flex;align-items:center;gap:8px}
.top-links{display:none;gap:18px;font-size:13.5px;color:var(--ink2);margin-right:8px}
.top-links a:hover{color:var(--accent)}
.icon-btn{background:var(--card);border:1px solid var(--border);border-radius:999px;width:38px;height:38px;display:inline-flex;align-items:center;justify-content:center;cursor:pointer;color:var(--ink2);transition:border-color .15s,color .15s}
.icon-btn:hover{border-color:var(--accent);color:var(--accent)}
.icon-btn svg{width:16px;height:16px;stroke:currentColor;stroke-width:1.8;fill:none;stroke-linecap:round;stroke-linejoin:round}

/* ── Buttons ── */
.btn-ig{display:inline-flex;align-items:center;gap:7px;background:var(--ink);color:var(--bg);font-size:13px;font-weight:500;padding:9px 20px;border-radius:999px;transition:opacity .15s}
.btn-ig:hover{opacity:.85}
.btn-ig svg{width:14px;height:14px;stroke:currentColor;stroke-width:2;fill:none;stroke-linecap:round;stroke-linejoin:round}

/* ── Cover（真圖 / gradient fallback）── */
.cover{position:relative;border-radius:13px;overflow:hidden;aspect-ratio:16/9}
.cover img{width:100%;height:100%;object-fit:cover}
.cover-fallback{width:100%;height:100%;display:flex;align-items:center;justify-content:center;font-size:52px}
.cover-pill{position:absolute;font-size:12px;font-weight:500;padding:5px 12px;border-radius:999px;background:var(--pill);color:var(--ink);backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px)}
.pill-cat{top:10px;left:10px}
.pill-date{top:10px;right:10px;color:var(--ink2)}
.g-tutorial{background:linear-gradient(135deg,#5B4FE8 0%,#8b7ff5 55%,#c7c0fb 100%)}
.g-analysis{background:linear-gradient(135deg,#0d9488 0%,#2dd4bf 60%,#99f6e4 100%)}
.g-security{background:linear-gradient(135deg,#b91c1c 0%,#f87171 60%,#fecaca 100%)}
.g-industry{background:linear-gradient(135deg,#b45309 0%,#f59e0b 60%,#fde68a 100%)}
.g-tech{background:linear-gradient(135deg,#1d4ed8 0%,#60a5fa 60%,#bfdbfe 100%)}
.g-playbook{background:linear-gradient(135deg,#be185d 0%,#ec4899 60%,#fbcfe8 100%)}
.g-default{background:linear-gradient(135deg,#334155 0%,#94a3b8 60%,#e2e8f0 100%)}

/* ── IG CTA 卡 ── */
.cta-card{padding:26px 22px;background:var(--surface);border:1px solid var(--border);border-radius:20px;text-align:center}
.cta-title{font-size:18px;font-weight:700}
.cta-sub{font-size:13.5px;color:var(--ink2);margin:8px 0 16px}

/* ── Footer ── */
.site-footer{border-top:1px solid var(--border);padding:20px 0 calc(86px + env(safe-area-inset-bottom));text-align:center}
.footer-links{display:flex;justify-content:center;flex-wrap:wrap;gap:6px 18px;font-size:12.5px;color:var(--ink3);margin-bottom:10px}
.footer-links a:hover{color:var(--accent)}
.copyright{font-size:11px;color:var(--ink3);letter-spacing:.05em}

/* ── Bottom nav ── */
.bottom-nav{position:fixed;left:0;right:0;bottom:0;background:var(--nav-bg);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-top:1px solid var(--border);z-index:50}
.bn-inner{max-width:600px;margin:0 auto;display:flex}
.bn-item{flex:1;display:flex;flex-direction:column;align-items:center;gap:3px;padding:10px 4px calc(10px + env(safe-area-inset-bottom));color:var(--ink3);font-size:10px;font-weight:500;letter-spacing:.04em;transition:color .15s}
.bn-item svg{width:21px;height:21px;stroke:currentColor;stroke-width:1.8;fill:none;stroke-linecap:round;stroke-linejoin:round}
.bn-item.active,.bn-item:hover{color:var(--accent)}

/* ════════════════════════════════════════════
   首頁 feed
   ════════════════════════════════════════════ */
.page-title{padding:18px 0 6px}
.page-title h1{font-size:30px;font-weight:900;line-height:1.3}
.page-title p{font-size:14px;color:var(--ink3);margin-top:6px}
.feed{padding:16px 0 28px;display:flex;flex-direction:column;gap:18px}
.card{display:block;background:var(--card);border:1px solid var(--border);border-radius:20px;padding:12px 12px 18px;transition:border-color .15s,transform .15s}
.card:hover{border-color:var(--accent)}
.card:active{transform:scale(.985)}
.card-body{padding:14px 8px 0}
.card-title{font-size:20px;font-weight:700;line-height:1.45}
.card:hover .card-title{color:var(--accent)}
.card-dek{font-size:14px;color:var(--ink2);margin-top:7px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.card-meta{display:flex;align-items:center;justify-content:space-between;margin-top:12px;font-size:12.5px;color:var(--ink3)}
.card-meta .read-link{color:var(--accent);font-weight:500}
.feed-loading{padding:48px 0;text-align:center;color:var(--ink3);font-size:14px}

/* ════════════════════════════════════════════
   文章頁
   ════════════════════════════════════════════ */
.art-hero{margin-top:10px}
.art-headline{font-size:28px;font-weight:900;line-height:1.4;margin-top:20px}
.art-deck{font-size:15.5px;color:var(--ink2);margin-top:12px;line-height:1.75}
.art-author{display:flex;align-items:center;gap:11px;margin-top:18px}
.art-author-avatar{width:42px;height:42px;border-radius:50%;overflow:hidden;flex-shrink:0}
.art-author-avatar img{width:100%;height:100%;object-fit:cover}
.art-author-name{font-size:14px;font-weight:500}
.art-author-meta{font-size:12.5px;color:var(--ink3)}
.art-actions{display:flex;align-items:center;gap:10px;margin:18px 0 6px;padding-bottom:22px;border-bottom:1px solid var(--border)}
.art-actions .btn-ig{flex:1;justify-content:center}

/* keypoints */
.keybox{margin:24px 0 6px;padding:18px 20px;background:var(--surface);border:1px solid var(--border);border-radius:16px}
.keybox-title{font-size:12px;font-weight:700;letter-spacing:.12em;color:var(--accent);text-transform:uppercase;margin-bottom:8px}
.keybox ul{list-style:none}
.keybox li{font-size:13.5px;color:var(--ink2);padding:4px 0 4px 20px;position:relative}
.keybox li::before{content:'→';position:absolute;left:0;color:var(--accent)}

/* 內文 */
.art-body{padding:10px 0 8px;font-size:16.5px;line-height:1.95;color:var(--ink)}
.art-body p{margin:18px 0}
.art-body a{color:var(--accent);text-decoration:underline;text-underline-offset:3px}
.art-body strong{font-weight:700}
.art-body h2{font-size:22px;font-weight:700;line-height:1.5;margin:38px 0 6px}
.art-body h3{font-size:18px;font-weight:700;margin:30px 0 4px}
.art-body ul,.art-body ol{margin:18px 0;padding-left:24px}
.art-body li{margin:7px 0}
.pullquote{margin:26px 0;padding:18px 22px;border-left:3px solid var(--accent);background:var(--surface);border-radius:0 14px 14px 0;font-size:17px;font-weight:600;line-height:1.8;color:var(--ink2)}
.pro-tip{margin:24px 0;padding:16px 20px;background:var(--surface);border:1px solid var(--border);border-left:3px solid var(--amber);border-radius:0 14px 14px 0;font-size:14.5px;line-height:1.8;color:var(--ink2)}
.pro-tip-label{font-size:12px;font-weight:700;letter-spacing:.08em;color:var(--amber);margin-bottom:6px}
.warn-box{margin:24px 0;padding:16px 20px;background:var(--surface);border:1px solid var(--border);border-left:3px solid var(--red);border-radius:0 14px 14px 0;font-size:14.5px;line-height:1.8;color:var(--ink2)}
.warn-label{font-size:12px;font-weight:700;letter-spacing:.08em;color:var(--red);margin-bottom:6px}
.art-figure{margin:26px 0;border:1px solid var(--border);border-radius:16px;overflow:hidden;background:var(--card)}
.art-figure img{width:100%}
.art-figure--svg{padding:14px}
.art-figure--svg svg{width:100%;height:auto}
.art-figure figcaption{padding:12px 16px;font-size:12.5px;color:var(--ink3);line-height:1.7;border-top:1px solid var(--border)}
.code-block{position:relative;margin:24px 0;background:var(--surface);border:1px solid var(--border);border-radius:16px}
.code-block pre{padding:18px 20px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:13px;line-height:1.8;color:var(--ink2);white-space:pre-wrap;word-break:break-word;max-height:340px;overflow-y:auto}
.code-copy{position:absolute;top:10px;right:10px;background:var(--card);border:1px solid var(--border);border-radius:999px;padding:5px 14px;font-family:-apple-system,BlinkMacSystemFont,"PingFang HK","PingFang TC","Microsoft JhengHei",sans-serif;font-size:12px;font-weight:500;color:var(--ink2);cursor:pointer;transition:border-color .15s,color .15s}
.code-copy:hover{border-color:var(--accent);color:var(--accent)}
.quiz-card{margin:26px 0;padding:24px 22px;background:var(--surface);border:1px solid var(--border);border-radius:16px;text-align:center}
.quiz-card-title{font-size:17px;font-weight:700}
.quiz-card a{display:inline-block;margin-top:12px;font-size:13.5px;font-weight:500;color:var(--accent)}

/* 文末 */
.art-tags{display:flex;flex-wrap:wrap;gap:8px;padding:24px 0 6px;border-top:1px solid var(--border)}
.art-tag{font-size:12px;color:var(--ink2);background:var(--surface);border:1px solid var(--border);padding:5px 14px;border-radius:999px}
.art-sources{font-size:12px;color:var(--ink3);padding:10px 0 24px}
.more-section{padding:30px 0 28px}
.more-title{font-size:22px;font-weight:700;margin-bottom:6px}
.more-item{display:flex;gap:14px;padding:18px 0;border-bottom:1px solid var(--border)}
.more-thumb{width:104px;height:74px;border-radius:12px;overflow:hidden;flex-shrink:0;position:relative}
.more-thumb img{width:100%;height:100%;object-fit:cover}
.more-thumb .cover-fallback{font-size:30px}
.more-info{flex:1;min-width:0}
.more-meta{font-size:11.5px;color:var(--ink3);display:flex;gap:8px;align-items:center}
.more-meta .cat{color:var(--accent);font-weight:500}
.more-headline{font-size:16px;font-weight:700;line-height:1.5;margin-top:3px}
.more-item:hover .more-headline{color:var(--accent)}
.more-dek{font-size:12.5px;color:var(--ink3);margin-top:3px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.more-home{display:block;text-align:right;padding:16px 0;font-size:13.5px;font-weight:500;color:var(--accent)}
.art-loading{padding:64px 0;text-align:center;color:var(--ink3);font-size:14px}
.art-loading a{color:var(--accent)}

/* ════════════════════════════════════════════
   關於頁（profile）
   ════════════════════════════════════════════ */
.profile-banner{position:relative;height:150px;border-radius:20px;background:var(--surface);overflow:hidden;margin-top:8px}
.profile-banner-pattern{position:absolute;inset:0;background-image:url('yai_logo.png');background-size:56px;background-repeat:space;opacity:.07}
.profile-head{text-align:center;margin-top:-44px;position:relative}
.profile-avatar{width:88px;height:88px;border-radius:50%;border:4px solid var(--bg);overflow:hidden;margin:0 auto;background:var(--bg)}
.profile-avatar img{width:100%;height:100%;object-fit:cover}
.profile-name{font-size:25px;font-weight:900;margin-top:12px}
.profile-handle{font-size:13px;color:var(--ink3);margin-top:4px}
.profile-bio{font-size:14.5px;color:var(--ink2);margin:16px auto 0;max-width:480px;text-align:center;line-height:1.85}
.profile-socials{display:flex;justify-content:center;gap:10px;margin-top:18px;padding-bottom:26px;border-bottom:1px solid var(--border)}

/* ════════════════════════════════════════════
   工具頁
   ════════════════════════════════════════════ */
.soon-badge{display:inline-block;font-size:11.5px;font-weight:500;color:var(--accent);background:var(--surface);border:1px solid var(--border);padding:4px 14px;border-radius:999px;margin-top:10px}
.tool-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:20px 0 26px}
.tool-card{background:var(--card);border:1px solid var(--border);border-radius:20px;padding:22px 16px;text-align:center}
.tool-emoji{font-size:30px;line-height:1}
.tool-name{font-size:15.5px;font-weight:700;margin-top:10px}
.tool-desc{font-size:12.5px;color:var(--ink3);margin-top:4px;line-height:1.7}

/* ── Desktop ── */
@media (min-width:768px){
  .bottom-nav{display:none}
  .top-links{display:flex}
  .site-footer{padding-bottom:28px}
  .page-title h1{font-size:34px}
  .art-headline{font-size:34px}
}