CSS
* {
    box-sizing: border-box;
    margin: 0; padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #0f172a;
    display: flex; justify-content: center; align-items: center;
    min-height: 100vh; padding: 20px; color: #f8fafc;
}

.card {
    background: #1e293b; padding: 25px; border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.5);
    width: 100%; max-width: 450px; text-align: center; border: 1px solid #334155;
}

.brand-header {
    font-size: 0.85rem; font-weight: 800; letter-spacing: 2px;
    color: #94a3b8; text-transform: uppercase; margin-bottom: 20px; text-align: left;
}

.panel-top-row {
    display: flex; justify-content: space-between; align-items: center;
    margin-bottom: 15px; border-bottom: 1px solid #334155; padding-bottom: 10px;
}
.panel-top-row .brand-header { margin-bottom: 0; }

.btn-logout-style {
    background: #ef4444; color: white; border: none;
    padding: 6px 12px; border-radius: 4px; cursor: pointer;
    font-size: 0.75rem; font-weight: bold;
}

h2 { margin-bottom: 10px; font-size: 1.4rem; }
p { color: #94a3b8; margin-bottom: 25px; font-size: 0.9rem; }
.input-group { text-align: left; margin-bottom: 15px; }
label { display: block; margin-bottom: 5px; color: #cbd5e1; font-size: 0.85rem; }

input, .select-estilo {
    width: 100%; padding: 12px; border-radius: 6px;
    border: 1px solid #475569; background: #0f172a; color: #fff; font-size: 1rem;
}

.btn-submit {
    width: 100%; padding: 12px; background: #2563eb; color: white;
    border: none; border-radius: 6px; font-size: 1rem; cursor: pointer; font-weight: bold;
}

.actions-container { display: flex; gap: 10px; margin-bottom: 20px; }
.btn-nav { flex: 2; padding: 12px; background: #10b981; color: white; border: none; border-radius: 6px; font-weight: bold; cursor: pointer;}
.btn-action { flex: 1; padding: 12px; background: #64748b; color: white; border: none; border-radius: 6px; cursor: pointer;}

.grid-unidades {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px;
    max-height: 250px; overflow-y: auto; padding: 10px 5px;
    background: #0f172a; border-radius: 8px; border: 1px solid #334155;
}

.btn-unidad {
    background: #334155; color: #fff; border: 1px solid #475569;
    padding: 12px 5px; border-radius: 6px; font-weight: bold; cursor: pointer; font-size: 0.9rem;
}
.btn-unidad:hover { background: #fb923c; color: #000; }

.modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(15, 23, 42, 0.85); backdrop-filter: blur(5px);
    display: flex; justify-content: center; align-items: center; z-index: 1000;
}
.modal-box {
    background: #1e293b; padding: 30px; border-radius: 12px;
    width: 90%; max-width: 400px; text-align: center; border: 2px solid #475569;
    box-shadow: 0 20px 40px rgba(0,0,0,0.6);
}
.modal-clave-contenedor { padding: 20px; border-radius: 8px; margin: 15px 0; color: #000; font-weight: bold; }
.modal-clave-contenedor p { font-size: 1.8rem; letter-spacing: 2px; color: #000; margin-bottom: 0; }

.bg-azul { background-color: #38bdf8; }
.bg-naranja { background-color: #fb923c; }
.bg-amarillo { background-color: #facc15; }
.bg-rojo { background-color: #f87171; }
.hidden { display: none !important; }

.demo-footer {
    width: 100%; max-width: 450px; margin: 18px auto 0; padding: 12px;
    text-align: center; color: #94a3b8; font-size: 0.72rem; line-height: 1.5;
}
.demo-footer strong { color: #f8fafc; letter-spacing: 1px; }
.demo-footer span { color: #fb923c; }