:root{--text:#0f172a;--muted:#64748b;--subtle:#94a3b8;--line:#94a3b83d;--blue:#2563eb;--indigo:#6366f1;--violet:#8b5cf6;--ease:cubic-bezier(.2, .8, .2, 1)}*{box-sizing:border-box}html{min-height:100%;overflow-x:hidden}body{min-height:100%;color:var(--text);background:radial-gradient(circle at 50% 0,#6366f11f,#0000 36%),radial-gradient(circle at 84% 18%,#a855f714,#0000 28%),linear-gradient(#f8fafc 0%,#eef2f7 100%);margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;overflow-x:hidden}body:before{z-index:-1;pointer-events:none;content:"";background:linear-gradient(#ffffff80,#fff0),radial-gradient(circle at 50% 8%,#2563eb12,#0000 24%);position:fixed;inset:0}button,input{font:inherit}.chat-shell{width:min(980px,100% - 32px);min-height:100vh;animation:pageIn .22s var(--ease) both;flex-direction:column;margin:0 auto;display:flex}.hero{text-align:center;padding:clamp(38px,7vh,72px) 16px 22px}.hero h1{letter-spacing:-.04em;justify-content:center;align-items:flex-start;margin:0;font-size:clamp(44px,7vw,64px);font-weight:900;line-height:.95;display:inline-flex}.hero h1 span{color:var(--text)}.hero h1 strong{color:#0000;-webkit-text-fill-color:transparent;background:linear-gradient(90deg,#2563eb 0%,#6366f1 45%,#a855f7 100%);-webkit-background-clip:text;background-clip:text}.hero h1 small{color:#6366f1bf;letter-spacing:0;margin:0 0 0 8px;font-family:Caveat,Pacifico,Dancing Script,cursive;font-size:clamp(18px,2vw,22px);font-weight:700;transform:translateY(4px)rotate(-6deg)}.hero p{color:var(--muted);letter-spacing:.02em;margin:14px 0 0;font-size:15.5px;font-weight:400}.messages{flex:1;width:min(900px,100%);margin:0 auto;padding:24px 0 132px}.examples{-webkit-backdrop-filter:blur(18px);background:#ffffffb8;border:1px solid #94a3b838;border-radius:28px;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;width:min(900px,100%);margin:0 auto;padding:clamp(26px,4vw,36px);display:grid;position:relative;overflow:hidden;box-shadow:0 24px 80px #0f172a14,inset 0 1px #fffc}.examples:before{color:var(--muted);content:"可咨询沥青试验标准、材料性能、文献知识与工程应用问题";text-align:center;grid-column:1/-1;margin-bottom:6px;font-size:14px;line-height:1.6;display:block}.examples:after{pointer-events:none;content:"";background:radial-gradient(circle,#6366f11f,#0000 70%);border-radius:999px;width:360px;height:180px;position:absolute;inset:-80px auto auto 50%;transform:translate(-50%)}.examples button{z-index:1;color:#1e293b;cursor:pointer;min-height:50px;transition:transform .18s var(--ease), border-color .18s var(--ease), box-shadow .18s var(--ease), background .18s var(--ease);background:linear-gradient(#ffffffeb,#f8fafcdb);border:1px solid #94a3b847;border-radius:16px;padding:0 18px;font-size:14px;font-weight:500;position:relative;box-shadow:0 6px 20px #0f172a0a}.examples button:hover{background:linear-gradient(#fff,#f5f7ff);border-color:#6366f18c;transform:translateY(-2px);box-shadow:0 12px 30px #6366f11f}.examples button:active{transform:translateY(0);box-shadow:0 5px 16px #0f172a0f}.bubble{max-width:78%;color:var(--text);-webkit-backdrop-filter:blur(14px);animation:messageIn .18s var(--ease) both;background:#ffffffd6;border:1px solid #94a3b838;border-radius:18px;margin:18px 0;padding:16px 18px;line-height:1.75;box-shadow:0 10px 32px #0f172a0b}.bubble.user{background:linear-gradient(135deg,#2563eb1a,#8b5cf61f);border-color:#6366f138;margin-left:auto}.bubble.assistant{margin-right:auto}.bubble p,.bubble h3{margin:0 0 10px}.bubble h3{color:var(--text);font-size:16px;font-weight:800}.bubble p:last-child,.bubble h3:last-child{margin-bottom:0}.followups{border-top:1px solid #94a3b82e;flex-wrap:wrap;gap:8px;margin-top:14px;padding-top:12px;display:flex}.followups button{color:#334155;cursor:pointer;min-height:34px;transition:transform .18s var(--ease), border-color .18s var(--ease), box-shadow .18s var(--ease), color .18s var(--ease);background:linear-gradient(#ffffffeb,#f8fafccc);border:1px solid #6366f138;border-radius:999px;padding:0 12px;font-size:13px;font-weight:600}.followups button:hover:not(:disabled){color:#3730a3;border-color:#6366f180;transform:translateY(-1px);box-shadow:0 8px 22px #6366f11f}.followups button:disabled{cursor:not-allowed;opacity:.5}.composer{width:min(900px,100% - 32px);margin-bottom:max(18px, env(safe-area-inset-bottom));-webkit-backdrop-filter:blur(18px);background:#ffffffdb;border:1px solid #94a3b840;border-radius:22px;gap:10px;padding:8px;display:flex;position:fixed;bottom:0;left:50%;transform:translate(-50%);box-shadow:0 20px 60px #0f172a14}.composer:before{z-index:-1;pointer-events:none;content:"";background:linear-gradient(#eef2f700,#eef2f7f5 62%);width:100%;min-width:min(900px,100vw - 32px);height:150px;position:fixed;bottom:-28px;left:50%;transform:translate(-50%)}.composer input{min-width:0;height:54px;color:var(--text);transition:background .18s var(--ease), box-shadow .18s var(--ease);background:#ffffff8c;border:0;border-radius:16px;flex:1;padding:0 18px;font-size:15px}.composer input::placeholder{color:var(--subtle)}.composer input:focus{background:#fff;outline:0;box-shadow:0 0 0 1px #6366f138,0 0 0 5px #6366f117}.composer button{color:#fff;cursor:pointer;min-width:82px;height:54px;transition:transform .18s var(--ease), box-shadow .18s var(--ease), opacity .18s var(--ease);background:linear-gradient(135deg,#2563eb 0%,#6366f1 48%,#8b5cf6 100%);border:0;border-radius:16px;font-weight:700;box-shadow:0 12px 28px #6366f147}.composer button:hover:not(:disabled){transform:translateY(-1px);box-shadow:0 16px 34px #6366f15c}.composer button:active:not(:disabled){transform:translateY(0);box-shadow:0 8px 20px #6366f138}.composer button:disabled{cursor:not-allowed;box-shadow:none;opacity:.55;background:linear-gradient(135deg,#94a3b8,#cbd5e1)}@keyframes pageIn{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}@keyframes messageIn{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}@media (max-width:720px){.chat-shell{width:min(100% - 24px,980px)}.hero{padding-top:34px}.hero h1{font-size:clamp(40px,13vw,46px)}.hero h1 small{font-size:18px}.hero p{font-size:14px}.messages{padding-top:18px;padding-bottom:124px}.examples{border-radius:22px;grid-template-columns:1fr;gap:12px;padding:22px}.bubble{border-radius:16px;max-width:92%}.composer{border-radius:18px;gap:8px;width:calc(100% - 24px)}.composer input,.composer button{border-radius:14px;height:50px}.composer button{min-width:72px}}