:root{--bg:#f5f7fb;--panel:#fff;--panel-soft:#eef3f8;--text:#17202a;--muted:#647386;--line:#d9e1ea;--brand:#0f766e;--brand-strong:#115e59;--danger:#c2410c;--danger-soft:#fff1e7;--shadow:0 14px 38px #1f2a3714}*{box-sizing:border-box}body{background:var(--bg);color:var(--text);margin:0;font-family:Arial,Microsoft YaHei,sans-serif}a{color:inherit;text-decoration:none}button,input,textarea,select{font:inherit}.app-shell{grid-template-columns:260px 1fr;min-height:100vh;display:grid}.sidebar{color:#f8fafc;background:#16212d;padding:24px 18px}.brand{align-items:center;gap:10px;margin-bottom:28px;font-size:20px;font-weight:700;display:flex}.brand-mark{background:var(--brand);border-radius:8px;place-items:center;width:36px;height:36px;display:grid}.nav{gap:6px;display:grid}.nav a,.nav button{color:#dbe7f2;cursor:pointer;text-align:left;background:0 0;border:0;border-radius:8px;align-items:center;gap:10px;width:100%;min-height:42px;padding:9px 10px;display:flex}.nav a:hover,.nav button:hover,.nav .active{color:#fff;background:#ffffff1a}.sidebar-footer{color:#bac7d4;border-top:1px solid #ffffff24;margin-top:28px;padding-top:18px;font-size:13px}.main{min-width:0;padding:28px}.topbar{justify-content:space-between;align-items:center;gap:16px;margin-bottom:22px;display:flex}.eyebrow{color:var(--muted);margin:0 0 6px;font-size:13px}h1,h2,h3,p{margin-top:0}h1{letter-spacing:0;margin-bottom:0;font-size:clamp(26px,4vw,38px)}.grid{grid-template-columns:minmax(320px,440px) minmax(0,1fr);gap:18px;display:grid}.panel{background:var(--panel);border:1px solid var(--line);box-shadow:var(--shadow);border-radius:8px}.panel-header{border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;gap:12px;padding:16px 18px;display:flex}.panel-body{padding:18px}.message-list{display:grid}.message-row{border-bottom:1px solid var(--line);gap:6px;padding:14px 18px;display:grid}.message-row:hover{background:#f8fbfd}.message-row.unread{background:#effaf8}.message-meta{color:var(--muted);justify-content:space-between;align-items:center;gap:10px;font-size:13px;display:flex}.subject-line{align-items:center;gap:8px;font-weight:700;display:flex}.badge{background:var(--panel-soft);min-height:22px;color:var(--muted);border-radius:999px;align-items:center;padding:2px 9px;font-size:12px;display:inline-flex}.empty{color:var(--muted);text-align:center;padding:32px}.message-body{white-space:pre-wrap;line-height:1.7}.actions{flex-wrap:wrap;gap:10px;display:flex}.button,button.button{background:var(--brand);color:#fff;cursor:pointer;border:1px solid #0000;border-radius:8px;justify-content:center;align-items:center;gap:8px;min-height:40px;padding:8px 14px;font-weight:700;display:inline-flex}.button.secondary{border-color:var(--line);color:var(--text);background:#fff}.button.danger{background:var(--danger)}.button.icon{width:40px;padding:0}.form{gap:14px;display:grid}.field{gap:6px;display:grid}.field label{color:var(--muted);font-size:13px;font-weight:700}.field input,.field textarea,.field select{border:1px solid var(--line);width:100%;color:var(--text);background:#fff;border-radius:8px;padding:11px 12px}.field textarea{resize:vertical;min-height:260px}.auth-page{background:linear-gradient(120deg, #0f766e1a, transparent 42%), var(--bg);place-items:center;min-height:100vh;padding:24px;display:grid}.auth-card{border:1px solid var(--line);width:min(100%,440px);box-shadow:var(--shadow);background:#fff;border-radius:8px;padding:28px}.auth-switch{color:var(--muted);margin-top:16px}.alert{background:var(--danger-soft);color:var(--danger);border-radius:8px;padding:12px 14px}.table{border-collapse:collapse;width:100%}.table th,.table td{border-bottom:1px solid var(--line);text-align:left;padding:12px}.table th{color:var(--muted);font-size:13px}@media (max-width:900px){.app-shell{grid-template-columns:1fr}.sidebar{z-index:10;position:sticky;top:0}.nav{grid-template-columns:repeat(2,minmax(0,1fr))}.grid{grid-template-columns:1fr}}@media (max-width:560px){.main{padding:18px}.topbar,.panel-header,.message-meta{flex-direction:column;align-items:flex-start}.nav{grid-template-columns:1fr}}