:root{
  --bg:#f5f7fb;
  --accent:#4e7cff;
  --muted:#6b7280;
  --card:#ffffff;
  --danger:#ef4444;
}
*{box-sizing:border-box}
body{
  margin:0;font-family:Inter,system-ui,Segoe UI,Roboto,"Helvetica Neue",Arial;
  background:var(--bg);color:#111;
  -webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;
}
.app{display:flex;min-height:100vh}

/* Sidebar */
.sidebar{
  width:260px;padding:18px;background:linear-gradient(180deg,#fff,#f7f9ff);
  border-right:1px solid rgba(16,24,40,0.06);
}
.compose{
  width:100%;padding:12px 16px;border-radius:8px;background:var(--accent);color:#fff;border:none;font-weight:600;margin-bottom:16px;cursor:pointer;
}
.folders button, .labels button{
  display:flex;justify-content:space-between;align-items:center;width:100%;padding:8px;border-radius:6px;border:none;background:transparent;text-align:left;cursor:pointer;color:#111;margin-bottom:6px;
}
.folders button.active{background:rgba(78,124,255,0.12)}
.count{font-size:12px;color:var(--muted);margin-left:8px}
.labels h4{margin:10px 0 6px;font-size:12px;color:var(--muted)}
.small{font-size:12px;color:var(--muted);margin-top:12px}

/* Main */
.main{flex:1;display:flex;flex-direction:column}
.topbar{display:flex;gap:12px;align-items:center;padding:12px 18px;border-bottom:1px solid rgba(16,24,40,0.06);background:linear-gradient(90deg,#fff,#fbfdff)}
.topbar input[type=search]{flex:1;padding:10px 12px;border-radius:8px;border:1px solid rgba(16,24,40,0.06)}
.top-actions button{border:none;background:transparent;font-size:18px;cursor:pointer}

/* content area */
.content{display:flex;flex:1;min-height:0}
.list-pane{width:420px;border-right:1px solid rgba(16,24,40,0.04);display:flex;flex-direction:column;overflow:auto}
.list-toolbar{display:flex;justify-content:space-between;align-items:center;padding:12px}
.list-toolbar button{margin-left:6px;padding:6px 8px;border-radius:6px;border:1px solid rgba(16,24,40,0.06);background:transparent;cursor:pointer}
.email-list{list-style:none;margin:0;padding:0}
.email-row{display:flex;align-items:flex-start;padding:12px;border-bottom:1px solid rgba(16,24,40,0.03);cursor:pointer}
.email-row:hover{background:rgba(78,124,255,0.03)}
.email-left{width:40px;height:40px;border-radius:50%;display:flex;align-items:center;justify-content:center;background:#eef2ff;color:var(--accent);font-weight:700;margin-right:10px}
.email-meta{flex:1}
.email-sub{font-weight:600;margin-bottom:6px}
.email-snippet{color:var(--muted);font-size:13px}
.email-time{font-size:12px;color:var(--muted);margin-left:8px}

/* detail pane */
.detail-pane{flex:1;padding:20px;overflow:auto;min-width:0}
.empty-detail{color:var(--muted);display:flex;flex-direction:column;align-items:center;justify-content:center;height:100%}
.email-detail header h2{margin:0 0 8px}
.meta{color:var(--muted);font-size:13px;margin-bottom:14px}
.body{white-space:pre-wrap;line-height:1.6}
.detail-actions{margin-top:18px}
.detail-actions button{margin-right:8px;padding:8px 10px;border-radius:6px;border:1px solid rgba(16,24,40,0.06);background:transparent;cursor:pointer}

/* modal compose */
.modal{position:fixed;inset:0;display:none;align-items:center;justify-content:center;background:rgba(2,6,23,0.3)}
.modal[aria-hidden="false"]{display:flex}
.modal-content{background:var(--card);width:720px;max-width:96%;border-radius:10px;box-shadow:0 8px 30px rgba(2,6,23,0.2);overflow:hidden}
.modal-content header{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;border-bottom:1px solid rgba(16,24,40,0.06)}
.modal-body{padding:12px 16px;display:flex;flex-direction:column;gap:8px}
.modal-body input, .modal-body textarea, .modal-body select{padding:10px;border-radius:8px;border:1px solid rgba(16,24,40,0.06)}
.modal-actions{display:flex;justify-content:space-between;align-items:center;margin-top:8px}
.primary{background:var(--accent);color:#fff;padding:8px 12px;border-radius:8px;border:none}

/* responsive */
@media (max-width:900px){
  .list-pane{width:320px}
  .sidebar{display:none}
}
@media (max-width:600px){
  .email-row{padding:10px}
  .topbar{padding:8px}
}