:root{
  --brand:#5b5bef;--brand2:#8b5cf6;--accent:#6366f1;
  --bg:#f4f5fb;--panel:#ffffff;--text:#1f2430;--muted:#8a90a6;
  --line:#eceef5;--shadow:0 10px 30px rgba(30,35,80,.08);
  --radius:16px;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;line-height:1.5}
.hidden{display:none !important}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
input,textarea{font-family:inherit;font-size:15px;color:var(--text)}

/* ---------- 认证页 ---------- */
.auth-wrap{min-height:100vh;display:grid;place-items:center;padding:24px;
  background:linear-gradient(135deg,#6a5cff 0%,#8b5cf6 45%,#d946a6 100%)}
.auth-wrap::before{content:"";position:fixed;inset:0;
  background:radial-gradient(60% 50% at 80% 10%,rgba(255,255,255,.25),transparent),
            radial-gradient(50% 40% at 10% 90%,rgba(255,255,255,.15),transparent)}
.auth-card{position:relative;width:100%;max-width:420px;background:rgba(255,255,255,.96);
  backdrop-filter:blur(12px);border-radius:24px;box-shadow:0 30px 60px rgba(20,20,60,.35);padding:36px 34px}
.brand{display:flex;align-items:center;gap:14px;margin-bottom:26px}
.brand-logo{width:52px;height:52px;border-radius:16px;display:grid;place-items:center;font-size:26px;
  background:linear-gradient(135deg,var(--brand),var(--brand2));box-shadow:0 8px 18px rgba(91,91,239,.4)}
.brand h1{font-size:23px;letter-spacing:.3px}
.brand-sub{color:var(--muted);font-size:13px;margin-top:2px}
.tabs{display:flex;background:#f0f1f8;border-radius:12px;padding:5px;margin-bottom:22px}
.tab{flex:1;padding:10px;border-radius:9px;font-size:15px;font-weight:600;color:var(--muted);transition:.2s}
.tab.active{background:#fff;color:var(--brand);box-shadow:0 2px 8px rgba(0,0,0,.06)}
.auth-form label{display:block;font-size:13px;font-weight:600;color:#5a6079;margin:14px 0 6px}
.auth-form input{width:100%;padding:13px 14px;border:1.5px solid var(--line);border-radius:12px;background:#fafbff;transition:.2s}
.auth-form input:focus{outline:none;border-color:var(--brand);background:#fff;box-shadow:0 0 0 4px rgba(91,91,239,.12)}
.domain-hint{font-size:12.5px;color:var(--brand);font-weight:600;margin-top:6px}
.btn-primary{width:100%;margin-top:24px;padding:14px;border-radius:12px;font-size:16px;font-weight:700;color:#fff;
  background:linear-gradient(135deg,var(--brand),var(--brand2));box-shadow:0 10px 22px rgba(91,91,239,.4);transition:.2s}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 14px 26px rgba(91,91,239,.5)}
.btn-primary:active{transform:translateY(0)}
.form-msg{min-height:18px;margin-top:12px;text-align:center;font-size:13.5px;font-weight:600;color:#e0447a}

/* ---------- 主应用 ---------- */
.app{display:grid;grid-template-columns:250px 340px 1fr;height:100vh;overflow:hidden}
.sidebar{background:var(--panel);border-right:1px solid var(--line);display:flex;flex-direction:column;padding:18px 14px}
.side-brand{display:flex;align-items:center;gap:9px;font-weight:800;font-size:17px;padding:6px 8px 16px;color:var(--brand)}
.brand-logo.sm{width:34px;height:34px;border-radius:11px;font-size:18px}
.btn-compose{margin:0 4px 18px;padding:13px;border-radius:13px;font-size:15px;font-weight:700;color:#fff;
  background:linear-gradient(135deg,var(--brand),var(--brand2));box-shadow:0 8px 18px rgba(91,91,239,.35);transition:.2s}
.btn-compose:hover{transform:translateY(-1px);box-shadow:0 12px 22px rgba(91,91,239,.45)}
.folders{display:flex;flex-direction:column;gap:4px}
.folder{display:flex;align-items:center;gap:11px;padding:11px 13px;border-radius:11px;font-size:15px;font-weight:600;color:#565d78;transition:.15s}
.folder:hover{background:#f5f6fc}
.folder.active{background:linear-gradient(135deg,rgba(91,91,239,.12),rgba(139,92,246,.12));color:var(--brand)}
.f-ico{font-size:16px}.f-name{flex:1;text-align:left}
.badge{min-width:22px;height:22px;padding:0 7px;border-radius:11px;display:none;place-items:center;font-size:12px;font-weight:700;color:#fff;background:var(--accent)}
.badge:not(:empty){display:grid}
.badge.muted{background:#c7cbdc}
.side-foot{margin-top:auto;display:flex;align-items:center;gap:8px;padding-top:12px;border-top:1px solid var(--line)}
.me{display:flex;align-items:center;gap:10px;flex:1;min-width:0}
.avatar{width:38px;height:38px;border-radius:50%;display:grid;place-items:center;color:#fff;font-weight:700;font-size:15px;flex-shrink:0;
  background:linear-gradient(135deg,#f472b6,#8b5cf6)}
.me-info{min-width:0}#meName{font-size:14px;font-weight:700;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.me-mail{font-size:12px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.btn-ghost{padding:8px 12px;border-radius:10px;font-size:14px;font-weight:600;color:#565d78;transition:.15s}
.btn-ghost:hover{background:#eef0f8}
.btn-ghost.danger{color:#e0447a}.btn-ghost.danger:hover{background:#fdeaF1}

/* 列表 */
.list-pane{background:var(--panel);border-right:1px solid var(--line);display:flex;flex-direction:column;overflow:hidden}
.list-head{padding:20px 20px 12px;border-bottom:1px solid var(--line)}
.list-head h2{font-size:19px;margin-bottom:12px}
.search{display:flex;align-items:center;gap:8px;background:#f4f5fb;border-radius:11px;padding:9px 13px}
.search input{flex:1;border:none;background:none;outline:none;font-size:14px}
.msg-list{flex:1;overflow-y:auto}
.msg-item{padding:14px 18px;border-bottom:1px solid var(--line);cursor:pointer;transition:.12s;position:relative}
.msg-item:hover{background:#f8f9fe}
.msg-item.active{background:#f0f1fd}
.msg-item.active::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:var(--brand)}
.msg-top{display:flex;justify-content:space-between;align-items:baseline;gap:10px}
.msg-from{font-size:14px;font-weight:700;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.msg-item.unread .msg-from{color:var(--brand)}
.msg-time{font-size:12px;color:var(--muted);white-space:nowrap}
.msg-subject{font-size:14px;margin-top:3px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.msg-item.unread .msg-subject{font-weight:700}
.msg-preview{font-size:12.5px;color:var(--muted);margin-top:2px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.dot{display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--accent);margin-right:6px;vertical-align:middle}
.empty-list{padding:50px 20px;text-align:center;color:var(--muted);font-size:14px}

/* 阅读 */
.read-pane{display:flex;flex-direction:column;overflow:hidden;background:linear-gradient(180deg,#fbfbff,#f6f7fc)}
.read-empty{flex:1;display:grid;place-items:center;text-align:center;color:var(--muted)}
.read-empty .big{font-size:56px;margin-bottom:10px;opacity:.6}
.read-view{flex:1;overflow-y:auto;padding:22px 40px}
.read-toolbar{display:flex;gap:6px;justify-content:flex-end;margin-bottom:16px}
.read-subject{font-size:24px;font-weight:800;margin-bottom:16px;line-height:1.3}
.read-meta{display:flex;gap:12px;align-items:center;padding-bottom:18px;margin-bottom:18px;border-bottom:1px solid var(--line)}
.read-from{font-size:15px;font-weight:700}.read-to,.read-time{font-size:13px;color:var(--muted)}
.read-body{white-space:pre-wrap;word-wrap:break-word;font-family:inherit;font-size:15.5px;line-height:1.75;color:#2b3040}
.only-mobile{display:none}

/* 模态框 */
.modal{position:fixed;inset:0;background:rgba(20,20,45,.45);backdrop-filter:blur(3px);display:grid;place-items:center;z-index:50;padding:20px}
.modal-card{width:100%;max-width:600px;background:#fff;border-radius:18px;box-shadow:0 30px 70px rgba(0,0,0,.3);overflow:hidden;animation:pop .18s ease}
@keyframes pop{from{transform:translateY(12px) scale(.98);opacity:0}to{transform:none;opacity:1}}
.modal-head{display:flex;justify-content:space-between;align-items:center;padding:18px 22px;background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff}
.modal-head h3{font-size:17px}
#composeForm{display:flex;flex-direction:column}
#composeForm input,#composeForm textarea{border:none;border-bottom:1px solid var(--line);padding:14px 22px;outline:none;font-size:15px}
#composeForm input:focus,#composeForm textarea:focus{background:#fafbff}
#composeForm textarea{min-height:280px;resize:vertical;border-bottom:none;line-height:1.6}
.modal-foot{display:flex;justify-content:space-between;align-items:center;padding:14px 18px;border-top:1px solid var(--line)}
.send-btn{padding:11px 26px;border-radius:11px;font-weight:700;color:#fff;background:linear-gradient(135deg,var(--brand),var(--brand2));box-shadow:0 6px 16px rgba(91,91,239,.35)}
.send-btn:hover{transform:translateY(-1px)}
.compose-msg{font-size:13px;color:#e0447a;font-weight:600}

/* Toast */
#toast{position:fixed;bottom:28px;left:50%;transform:translateX(-50%) translateY(20px);background:#22263a;color:#fff;
  padding:13px 22px;border-radius:12px;font-size:14px;font-weight:600;box-shadow:0 12px 30px rgba(0,0,0,.3);opacity:0;transition:.25s;z-index:80;pointer-events:none}
#toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
#toast.ok{background:#16a34a}#toast.err{background:#e0447a}

/* 响应式 */
@media(max-width:860px){
  .app{grid-template-columns:1fr;grid-template-rows:auto 1fr}
  .sidebar{flex-direction:row;align-items:center;border-right:none;border-bottom:1px solid var(--line);padding:10px 14px;overflow-x:auto}
  .side-brand,.btn-compose{margin:0}
  .btn-compose{padding:9px 14px;font-size:14px;white-space:nowrap}
  .folders{flex-direction:row;gap:2px}.folder{padding:8px 10px}.f-name{display:none}
  .side-foot{margin:0 0 0 auto;border:none;padding:0}.me-info{display:none}
  .list-pane{display:flex}.read-pane{position:fixed;inset:0;z-index:40;transform:translateX(100%);transition:.22s}
  .app.reading .read-pane{transform:none}
  .only-mobile{display:inline-block}.read-view{padding:20px}
}
::-webkit-scrollbar{width:9px;height:9px}::-webkit-scrollbar-thumb{background:#d7dae8;border-radius:5px}
::-webkit-scrollbar-thumb:hover{background:#c2c6da}
.modal-foot .btn-primary{width:auto;margin:0;padding:11px 26px;border-radius:11px}
#appView.reading .list-pane{display:none}
#appView.reading .read-pane{display:flex}
#appView.reading .only-mobile{display:inline-flex}