:root{
  --bg:#f4f6f8;--card:#ffffff;--text:#16202a;--muted:#64748b;--border:#e2e8f0;
  --accent:#0d9488;--accent-soft:#ccfbf1;--danger:#dc2626;--danger-soft:#fee2e2;
  --shadow:0 1px 3px rgba(15,23,42,.08),0 8px 24px rgba(15,23,42,.06);
}
[data-theme="dark"]{
  --bg:#0f172a;--card:#1e293b;--text:#e2e8f0;--muted:#94a3b8;--border:#334155;
  --accent:#2dd4bf;--accent-soft:#134e4a;--danger:#f87171;--danger-soft:#450a0a;
  --shadow:0 1px 3px rgba(0,0,0,.4),0 8px 24px rgba(0,0,0,.3);
}
*{box-sizing:border-box}
body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--text);line-height:1.5}
a{color:var(--accent);text-decoration:none}
.topbar{display:flex;justify-content:space-between;align-items:center;padding:14px 20px;background:var(--card);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:5}
.brand{font-weight:700;letter-spacing:.5px}.logo-dot{display:inline-block;width:10px;height:10px;border-radius:50%;background:var(--accent);margin-right:6px}
.topnav{display:flex;gap:14px;align-items:center;font-size:14px}.topnav a{color:var(--muted)}
.icon-btn{background:none;border:1px solid var(--border);border-radius:8px;color:var(--text);cursor:pointer;padding:4px 10px;font-size:16px}
.container{max-width:760px;margin:0 auto;padding:24px 16px 60px}
.tagline{text-align:center;font-size:18px;color:var(--muted);margin:8px 0 20px}
.mailbox-card,.inbox-card,.viewer{background:var(--card);border:1px solid var(--border);border-radius:14px;box-shadow:var(--shadow);padding:18px;margin-bottom:18px}
.email-row{display:flex;gap:8px;flex-wrap:wrap}
.email-input{flex:1;min-width:200px;font-size:18px;font-weight:600;padding:12px 14px;border:2px solid var(--accent);border-radius:10px;background:var(--accent-soft);color:var(--text);font-family:ui-monospace,monospace}
.btn{background:var(--card);color:var(--text);border:1px solid var(--border);border-radius:10px;padding:10px 16px;font-size:14px;cursor:pointer;font-weight:600}
.btn:hover{border-color:var(--accent)}
.btn-primary{background:var(--accent);color:#fff;border-color:var(--accent)}
.btn-danger{color:var(--danger);border-color:var(--danger)}
.btn-small{padding:5px 10px;font-size:12px}
.mailbox-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px;align-items:center}
.ttl-select{padding:8px;border-radius:8px;border:1px solid var(--border);background:var(--card);color:var(--text)}
.meta-row{display:flex;gap:14px;align-items:center;margin-top:12px;font-size:13px;color:var(--muted)}
.status{width:8px;height:8px;border-radius:50%;display:inline-block}
.status.online{background:#16a34a}.status.offline{background:#94a3b8}.status.error{background:var(--danger)}
.inbox-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px}
.inbox-head h2{margin:0;font-size:16px}
.inbox-list{list-style:none;margin:0;padding:0}
.inbox-list li{padding:12px 10px;border-bottom:1px solid var(--border);cursor:pointer;display:flex;justify-content:space-between;gap:10px;align-items:center}
.inbox-list li:hover{background:var(--accent-soft)}
.inbox-list li.empty{cursor:default;color:var(--muted);justify-content:center}
.inbox-list li.unread{font-weight:700;border-left:3px solid var(--accent)}
.inbox-sender{font-size:14px;flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.inbox-subject{font-size:13px;color:var(--muted);font-weight:400;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.inbox-time{font-size:12px;color:var(--muted);white-space:nowrap}
.attach-ico{font-size:11px;color:var(--accent)}
.hidden{display:none!important}
.viewer-head h3{margin:8px 0 4px;font-size:17px}
.viewer-meta{font-size:13px;color:var(--muted)}
.otp-box,.link-box,.images-banner{margin:12px 0;padding:12px;border-radius:10px;background:var(--accent-soft);display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.otp-label{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.5px}
.otp-value{font-size:24px;font-weight:800;letter-spacing:4px;font-family:ui-monospace,monospace;color:var(--accent)}
.link-box a{word-break:break-all}
.tabs{display:flex;gap:4px;border-bottom:1px solid var(--border);margin:14px 0 10px}
.tab{background:none;border:none;padding:8px 14px;cursor:pointer;color:var(--muted);font-weight:600;border-bottom:2px solid transparent}
.tab.active{color:var(--accent);border-bottom-color:var(--accent)}
.tab-pane{display:none;min-height:120px}
.tab-pane.active{display:block}
#htmlFrame{width:100%;min-height:320px;border:1px solid var(--border);border-radius:8px;background:#fff}
#textPane,#sourcePane{white-space:pre-wrap;word-break:break-word;font-size:13px;background:var(--bg);padding:12px;border-radius:8px;max-height:420px;overflow:auto}
.attach-list{margin-top:12px;display:flex;flex-direction:column;gap:6px}
.attach-item{display:flex;justify-content:space-between;align-items:center;padding:8px 12px;border:1px solid var(--border);border-radius:8px;font-size:13px}
.modal{position:fixed;inset:0;background:rgba(0,0,0,.5);display:flex;align-items:center;justify-content:center;z-index:50}
.modal-box{background:var(--card);padding:20px;border-radius:14px;text-align:center;max-width:320px}
#qrCanvas{margin:12px auto;width:200px;height:200px;display:flex;align-items:center;justify-content:center}
.qr-email{font-family:ui-monospace,monospace;font-size:13px;word-break:break-all}
.footer{text-align:center;font-size:12px;color:var(--muted);padding:20px}
@media(max-width:480px){.email-input{font-size:15px}.btn{padding:9px 12px}}