:root {
    --bg-color: #f4f6f8;
    --surface-color: #ffffff;
    --primary-color: #1e293b; /* Tono oscuro elegante */
    --accent-color: #3b82f6;
    --text-main: #334155;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Inter', -apple-system, sans-serif; }

body { background-color: var(--bg-color); color: var(--text-main); }

/* Contenedor Login */
.login-container {
    height: 100vh; display: flex; justify-content: center; align-items: center; padding: 20px;
}
.login-box {
    background: var(--surface-color); padding: 40px; border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.05); width: 100%; max-width: 400px; text-align: center;
}
.login-box h2 { margin-bottom: 24px; color: var(--primary-color); }
input {
    width: 100%; padding: 12px 16px; margin-bottom: 16px; border: 1px solid var(--border-color);
    border-radius: 8px; outline: none; transition: 0.3s;
}
input:focus { border-color: var(--accent-color); }
button {
    width: 100%; padding: 12px; background: var(--primary-color); color: white;
    border: none; border-radius: 8px; cursor: pointer; font-weight: 600; transition: 0.3s;
}
button:hover { background: var(--accent-color); }

/* Layout Dashboard */
.dashboard { display: flex; min-height: 100vh; flex-direction: column; }
@media(min-width: 768px) { .dashboard { flex-direction: row; } }

/* Sidebar */
.sidebar {
    background: var(--surface-color); width: 100%; padding: 24px;
    border-right: 1px solid var(--border-color); display: flex; flex-direction: column; gap: 16px;
}
@media(min-width: 768px) { .sidebar { width: 280px; height: 100vh; position: sticky; top: 0; } }
.sidebar h3 { color: var(--primary-color); margin-bottom: 20px; font-size: 1.2rem;}
.sidebar a {
    text-decoration: none; color: var(--text-muted); padding: 10px 12px;
    border-radius: 6px; transition: 0.2s; font-weight: 500; display: block;
}
.sidebar a:hover { background: var(--bg-color); color: var(--primary-color); }
.logout-btn { margin-top: auto; color: #ef4444; }

/* Main Content */
.main-content { flex: 1; padding: 32px; }
.header-dash { display: flex; justify-content: space-between; align-items: center; margin-bottom: 32px; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.card { background: var(--surface-color); padding: 24px; border-radius: 12px; border: 1px solid var(--border-color); }
.card h4 { margin-bottom: 8px; color: var(--primary-color); }
.badge { display: inline-block; padding: 4px 10px; background: #e0f2fe; color: #0284c7; border-radius: 20px; font-size: 0.8rem; font-weight: 600; margin-bottom: 12px;}