:root{
  --bg: #F3F5F7;
  --surface: #FFFFFF;
  --surface-2: #FAFBFC;
  --border: #E3E7EC;
  --border-strong: #D3D9E0;
  --text: #1B1F24;
  --text-soft: #66707B;
  --text-faint: #98A1AA;
  --accent: #4F6BED;
  --accent-ink: #FFFFFF;
  --accent-soft: rgba(79,107,237,0.10);
  --danger: #D64545;
}
@media (prefers-color-scheme: dark){
  :root{
    --bg: #16191D;
    --surface: #1D2126;
    --surface-2: #22262C;
    --border: #2B3036;
    --border-strong: #3A4048;
    --text: #E8EAED;
    --text-soft: #A0A8B1;
    --text-faint: #6C7580;
    --accent-soft: rgba(79,107,237,0.18);
  }
}

*{ box-sizing: border-box; }
body{
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.hidden{ display: none !important; }

/* ---------- Login ---------- */
#loginScreen{
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.login-box{
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 32px;
  width: 320px;
  text-align: center;
}
.login-box h1{ font-size: 20px; margin: 0 0 20px; }
.login-box input{
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: var(--surface-2);
  color: var(--text);
  font-size: 14px;
  margin-bottom: 12px;
}
.login-box button{
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: none;
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}
.login-error{ color: var(--danger); font-size: 13px; min-height: 18px; margin-top: 8px; }

/* ---------- App ---------- */
header.app-header{
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}
header.app-header h1{ font-size: 18px; margin: 0; }
header.app-header .identity{ color: var(--accent); font-weight: 600; }
#logoutBtn{
  border: 1px solid var(--border-strong);
  background: var(--surface-2);
  color: var(--text-soft);
  border-radius: 8px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 13px;
}

main{
  max-width: 960px;
  margin: 0 auto;
  padding: 24px;
}
.placeholder{ color: var(--text-faint); font-size: 14px; }