:root{
  --bg:#07080a;
  --panel:#0f1720;
  --muted:#9aa6b2;
  --accent:#2b8cff;
  --maxwidth:1100px;
  font-family: Inter, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  color-scheme: dark;
}
*{box-sizing:border-box}
html,body{height:100%;margin:0;background:var(--bg);color:#e6eef8}
.screen{display:none;height:100%}
.screen.active{display:flex;align-items:center;justify-content:center}
.login-box{width:320px;padding:24px;background:linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));border-radius:12px;border:1px solid rgba(255,255,255,0.03);text-align:center}
.login-box h1{margin:0 0 8px;font-size:20px}
.login-box input{width:100%;padding:10px;margin:10px 0;border-radius:8px;border:1px solid rgba(255,255,255,0.06);background:rgba(255,255,255,0.02);color:inherit}
.login-box button{width:100%;padding:10px;border-radius:8px;border:none;background:var(--accent);color:#fff;font-weight:600}
.hint{font-size:12px;color:var(--muted);margin-top:10px}

/* App layout */
#app{display:flex;height:100vh;width:100%}
.sidebar{width:260px;background:var(--panel);padding:20px;display:flex;flex-direction:column;gap:12px}
.brand{font-weight:700;font-size:18px;margin-bottom:6px}
.sidebar nav{display:flex;flex-direction:column;gap:8px}
.navbtn{padding:10px;border-radius:8px;border:none;background:rgba(255,255,255,0.02);color:inherit;text-align:left;cursor:pointer}
.navbtn:hover{background:rgba(255,255,255,0.03)}
.bottom{margin-top:auto}
.bottom button{width:100%;padding:8px;border-radius:8px;border:none;background:#2b2f34;color:var(--muted)}

/* Main */
.main{flex:1;display:flex;align-items:stretch;padding:18px}
.viewer-wrap{position:relative;flex:1;background:#05060a;border-radius:8px;overflow:hidden;border:1px solid rgba(255,255,255,0.03)}
iframe{width:100%;height:100%;min-height:400px;border:0;display:block}

/* overlay for protection */
.overlay{position:absolute;inset:0;background:rgba(7,8,10,0.6);display:flex;align-items:center;justify-content:center;backdrop-filter:blur(3px)}
.overlay.hidden{display:none}
.overlay-msg{color:#fff;padding:12px 18px;border-radius:8px;background:rgba(0,0,0,0.4);border:1px solid rgba(255,255,255,0.04)}

/* Responsive */
@media (max-width:800px){
  .sidebar{position:fixed;left:0;top:0;bottom:0;width:220px;z-index:30;transform:translateX(-100%);transition:transform .2s}
  .sidebar.open{transform:translateX(0)}
  .main{padding:12px}
  .viewer-wrap{border-radius:0}
  #app.show-sidebar .sidebar{transform:translateX(0)}
}

iframe{width:100%;height:100vh;border:none;display:block;}