:root {
    /* Primary Colors */
    --primary-blue: #0088cc;      /* Water theme */
    --primary-teal: #00a9a5;      /* Energy theme */
    --secondary-blue: #e8f5fc;    /* Light water */
    --secondary-teal: #e6f6f6;    /* Light energy */

    /* Supporting Colors */
    --neutral-dark: #2c3e50;      /* Text and headings */
    --neutral-gray: #95a5a6;      /* Secondary text */
    --neutral-light: #ecf0f1;     /* Backgrounds */
    --success-green: #27ae60;     /* Success states */
    --warning-yellow: #f1c40f;    /* Warning states */
    --danger-red: #e74c3c;        /* Error states */

    /* Gradients */
    --water-gradient: linear-gradient(135deg, var(--primary-blue) 0%, var(--primary-teal) 100%);
    --energy-gradient: linear-gradient(135deg, var(--primary-teal) 0%, var(--primary-blue) 100%);

    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

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

/* Login Page Specific Styles */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    background: var(--water-gradient);
}

.login-card {
    width: 100%;
    max-width: 400px;
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.login-header {
    text-align: center;
    margin-bottom: 2rem;
}

.login-header img {
    max-width: 200px;
    margin-bottom: 1.5rem;
}

.login-header h1 {
    font-size: 1.75rem;
    color: var(--neutral-dark);
    margin-bottom: 0.5rem;
}

.login-header p {
    color: var(--neutral-gray);
}

.form-group {
    margin-bottom: 1.5rem;
}

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

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--neutral-light);
    border-radius: var(--radius-md);
    transition: var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px var(--secondary-blue);
}

.input-icon {
    position: relative;
}

.input-icon i {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--neutral-gray);
}

.input-icon input {
    padding-left: 2.5rem;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: var(--transition-fast);
    cursor: pointer;
    border: none;
    width: 100%;
}

.btn-primary {
    background: var(--water-gradient);
    color: white;
}

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

.alert {
    padding: 1rem;
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
}

.alert-danger {
    background-color: #fde8e8;
    color: var(--danger-red);
    border: 1px solid #fbd5d5;
}

.alert-success {
    background-color: #f0fff4;
    color: var(--success-green);
    border: 1px solid #c6f6d5;
}

/* Responsive Design */
@media (max-width: 768px) {
    .login-card {
        margin: 1rem;
        padding: 1.5rem;
    }

    .login-header img {
        max-width: 150px;
    }
}

/* Animation */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.login-card {
    animation: fadeIn 0.5s ease-out;
}