/* 樸素、像技術文件的版面 */
body{
  font-family: -apple-system, "Segoe UI", "PingFang TC", "Microsoft JhengHei", sans-serif;
  color:#222; background:#fff; line-height:1.75;
  max-width:760px; margin:0 auto; padding:40px 20px 80px;
}
h1{font-size:1.7rem;margin:0 0 4px}
.sub{color:#555;margin:0 0 8px}
h2{font-size:1.2rem;margin:36px 0 8px;padding-bottom:4px;border-bottom:1px solid #ddd}
h3{font-size:1.02rem;margin:22px 0 6px;color:#333}
p{margin:10px 0}
ul,ol{margin:10px 0;padding-left:22px}
li{margin:4px 0}
code{background:#f2f2f2;padding:1px 5px;border-radius:3px;font-size:.9em}
a{color:#1a5db5}
hr{border:none;border-top:1px solid #ddd;margin:36px 0 16px}
.foot{color:#777;font-size:.9rem}
.live{margin:8px 0 0}
.live a{display:inline-block;background:#333;color:#fff;text-decoration:none;padding:9px 18px;border-radius:6px;font-size:.95rem;font-weight:600}
.live a:hover{background:#000}

figure{margin:14px 0}
figure img{width:100%;height:auto;border:1px solid #ddd;border-radius:4px}

/* 聊天 */
.chat-fab{
  position:fixed;right:20px;bottom:20px;
  background:#333;color:#fff;border:none;border-radius:6px;
  padding:10px 16px;font-size:.9rem;cursor:pointer;
}
.chat-fab:hover{background:#000}
.chat-panel{
  position:fixed;right:20px;bottom:64px;width:340px;max-width:calc(100vw - 32px);
  height:460px;max-height:calc(100vh - 110px);
  background:#fff;border:1px solid #ccc;border-radius:6px;
  display:none;flex-direction:column;overflow:hidden;
  box-shadow:0 4px 16px rgba(0,0,0,.15);
}
.chat-panel.open{display:flex}

/* 思考中跳動圓點 */
.typing-dots{display:inline-flex;gap:5px;align-items:center;padding:2px 0}
.typing-dots span{width:7px;height:7px;border-radius:50%;background:#999;animation:typingBlink 1.2s infinite both}
.typing-dots span:nth-child(2){animation-delay:.2s}
.typing-dots span:nth-child(3){animation-delay:.4s}
@keyframes typingBlink{0%,80%,100%{opacity:.25;transform:translateY(0)}40%{opacity:1;transform:translateY(-4px)}}
.chat-head{display:flex;justify-content:space-between;align-items:center;
  padding:10px 12px;background:#f5f5f5;border-bottom:1px solid #ddd;font-size:.95rem;font-weight:600}
.chat-head button{background:none;border:none;font-size:1.2rem;cursor:pointer;color:#666;line-height:1}
.chat-body{flex:1;overflow-y:auto;padding:12px;display:flex;flex-direction:column;gap:8px}
.msg{max-width:88%;padding:8px 11px;border-radius:6px;font-size:.9rem;white-space:pre-wrap;word-break:break-word}
.msg.bot{background:#f2f2f2;align-self:flex-start}
.msg.user{background:#1a5db5;color:#fff;align-self:flex-end}
.msg.typing{color:#999}
.chat-input{display:flex;gap:6px;padding:10px;border-top:1px solid #ddd}
.chat-input input{flex:1;border:1px solid #ccc;border-radius:4px;padding:8px;font-size:.9rem;outline:none}
.chat-input input:focus{border-color:#1a5db5}
.chat-input button{border:none;background:#333;color:#fff;border-radius:4px;padding:0 14px;cursor:pointer;font-size:.9rem}
.chat-input button:disabled{opacity:.5;cursor:default}