:root {
  --bg:#0f0f0f; --bg2:#171717; --panel:#1f1f1f; --accent:#33c2ff;
  --text:#e9e9e9; --text-dim:#9a9a9a; --border:#2b2b2b; --danger:#ff4d4d;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial}
header{background:var(--panel);padding:12px 20px;border-bottom:1px solid var(--border);display:flex;justify-content:space-between;align-items:center;font-weight:600}
header span{color:var(--accent)}
header button{background:var(--accent);border:none;padding:8px 14px;border-radius:6px;font-weight:600;cursor:pointer;margin-left:8px}
#container{display:flex;height:calc(100vh - 58px)}
#mail-list{width:340px;background:var(--bg2);border-right:1px solid var(--border);overflow:auto}
.mail-item{padding:14px;border-bottom:1px solid var(--border);cursor:pointer}
.mail-item:hover{background:var(--panel)}
.mail-item .sender{font-weight:700}
.mail-item .subject{color:var(--text-dim);font-size:14px}
.mail-item .time{font-size:12px;margin-top:4px;color:var(--text-dim)}
#viewer{flex:1;padding:20px;overflow:auto}
#viewer iframe{width:100%;height:70vh;border:none;background:#fff}
.delete-btn{background:var(--danger);padding:8px 12px;border:none;border-radius:6px;cursor:pointer;margin-top:12px}