:root{--red:#c71935;--red-light:#fff2f3;--ink:#202127;--muted:#777b85;--line:#e6e5ea;--bg:#f7f7f9;--blue:#298cb8}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;font-size:16px;line-height:1.5;-webkit-font-smoothing:antialiased}
button,input,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid #b67b8b;outline-offset:2px}
header{background:#fff;border-bottom:1px solid var(--line)}
.header-inner{max-width:720px;margin:auto;height:72px;display:flex;align-items:center;justify-content:space-between;padding:0 16px}
.brand{color:var(--ink);display:flex;gap:12px;align-items:center;font-size:15px;letter-spacing:.5px;font-weight:800}
.brand img{border-radius:10px}
.brand small{display:block;font-size:11px;letter-spacing:0;font-weight:400;color:var(--muted);margin-top:3px}
.header-caption{color:var(--muted);font-size:13px}
main{max-width:720px;margin:auto;padding:20px 16px 24px}
.card{background:#fff;border-radius:18px;padding:22px 18px;box-shadow:0 4px 18px rgba(26,26,40,.06)}
h1{font-size:30px;letter-spacing:-.8px;line-height:1.2;margin:0 0 10px}
h1>span{color:var(--red)}
h2{font-size:19px;margin:0 0 4px}
.lead{color:var(--muted);margin:0 0 18px}
label{display:block;font-weight:600;font-size:14px;margin:14px 0 6px}
.req{color:var(--red)}
input,textarea{width:100%;padding:12px 14px;border:1.5px solid var(--line);border-radius:12px;background:#fff}
input:focus,textarea:focus{border-color:var(--blue);outline:none}
textarea{resize:vertical;min-height:52px}
.hint{color:var(--muted);font-size:13px;margin:6px 0 0}
label.check{display:flex;gap:10px;align-items:flex-start;font-weight:400;font-size:14px;margin-top:16px}
label.check input{width:20px;height:20px;flex:none;margin:1px 0 0;accent-color:var(--red)}
a{color:var(--blue)}
.btn{display:block;width:100%;margin-top:18px;padding:14px;border:0;border-radius:12px;background:var(--red);color:#fff;font-weight:700}
.btn:disabled{opacity:.6;cursor:default}
.text-button{border:0;background:none;color:var(--blue);padding:6px 0;font-size:14px;font-weight:600}
.text-button.muted{color:var(--muted);font-weight:400;margin-top:10px}
.notice{background:var(--red-light);color:#9b1028;border-radius:12px;padding:12px 14px;margin-bottom:14px}
.chat-head{display:flex;flex-direction:column;gap:6px;align-items:flex-start;border-bottom:1px solid var(--line);padding-bottom:12px}
.chat-head .text-button{white-space:nowrap}
.link-box{background:var(--bg);border-radius:12px;padding:10px 12px;margin-top:12px}
.link-box input{margin-top:8px;font-size:13px}
.messages{display:flex;flex-direction:column;gap:10px;padding:16px 0;min-height:120px}
.msg{max-width:86%;padding:10px 14px;border-radius:16px;white-space:pre-wrap;overflow-wrap:anywhere}
.msg.mine{align-self:flex-end;background:#e8f3f9;border-bottom-right-radius:6px}
.msg.theirs{align-self:flex-start;background:#f1f1f4;border-bottom-left-radius:6px}
.msg.system{align-self:center;background:none;color:var(--muted);font-size:13px;text-align:center;max-width:100%}
.msg .who{display:block;font-size:12px;font-weight:700;color:var(--red);margin-bottom:2px}
.msg .when{display:block;font-size:11px;color:var(--muted);margin-top:4px;text-align:right}
.msg img{display:block;max-width:100%;max-height:320px;border-radius:10px;margin-top:6px}
.msg .file{display:block;margin-top:6px}
.empty{color:var(--muted);text-align:center;font-size:14px}
.composer{display:flex;gap:10px;align-items:flex-end;border-top:1px solid var(--line);padding-top:12px}
.composer .btn{width:auto;margin:0;padding:13px 18px}
footer{max-width:720px;margin:auto;padding:0 16px 28px;color:var(--muted);font-size:12px;text-align:center}
@media (min-width:640px){.card{padding:28px 30px}h1{font-size:36px}.chat-head{flex-direction:row;justify-content:space-between;gap:12px}}