:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #64748b;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --info: #3b82f6;
    --dark: #1e293b;
    --light: #f8fafc;
    --gray: #94a3b8;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --radius: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background: #f1f5f9;
    color: var(--dark);
    line-height: 1.5;
}

/* Dashboard Layout */
.dashboard {
    display: flex;
    min-height: 100vh;
}

/* ============================================
   SIDEBAR PREMIUM
   ============================================ */
.sidebar {
    width: 280px;
    background: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
    color: white;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    transition: all 0.3s ease;
    z-index: 100;
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: rgba(255,255,255,0.1);
    border-radius: 3px;
}

.sidebar::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.3);
    border-radius: 3px;
}

.sidebar-header {
    padding: 1.75rem 1.5rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    margin-bottom: 1.5rem;
}

.sidebar-header h2 {
    font-size: 1.35rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.625rem;
    background: linear-gradient(135deg, #fff 0%, #94a3b8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-header h2::before {
    content: "⛽";
    font-size: 1.5rem;
    background: none;
    -webkit-text-fill-color: initial;
    color: #3b82f6;
}

.sidebar-nav {
    padding: 0 1rem;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.875rem;
    padding: 0.875rem 1rem;
    margin-bottom: 0.5rem;
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    border-radius: 12px;
    transition: all 0.3s ease;
    font-weight: 500;
    position: relative;
    overflow: hidden;
}

.nav-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 0;
    height: 100%;
    background: linear-gradient(90deg, rgba(59,130,246,0.2) 0%, transparent 100%);
    transition: width 0.3s ease;
}

.nav-item:hover::before {
    width: 100%;
}

.nav-item:hover {
    color: white;
    background: rgba(255,255,255,0.08);
    transform: translateX(4px);
}

.nav-item.active {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.nav-item.active::before {
    display: none;
}

.nav-item span:first-child {
    font-size: 1.25rem;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 280px;
    min-height: 100vh;
    background: #f1f5f9;
}

/* Top Bar */
.top-bar {
    background: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 50;
}

.page-title {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #1e293b 0%, #475569 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-name {
    font-weight: 500;
    color: var(--dark);
    font-size: 0.875rem;
}

.user-avatar {
    width: 42px;
    height: 42px;
    background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    color: white;
    font-size: 0.875rem;
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border);
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
    color: var(--secondary);
}

.btn-outline:hover {
    background: var(--light);
    border-color: var(--gray);
    color: var(--dark);
}

/* Container */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 2rem;
}

/* Botones */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-primary {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Formularios */
.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--dark);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.625rem 0.875rem;
    font-size: 0.875rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: all 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59,130,246,0.1);
}

/* Tarjetas */
.card {
    background: white;
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

/* Grid */
.form-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        position: fixed;
        z-index: 200;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .container {
        padding: 1rem;
    }
    
    .top-bar {
        padding: 0.75rem 1rem;
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .user-menu {
        width: 100%;
        justify-content: space-between;
    }
}