/* ============================================
   MODERN ELECTRICITY BILLING SYSTEM STYLES
   Professional & Clean Design - 2025
   ============================================ */

/* === ROOT VARIABLES === */
:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #3b82f6;
    --secondary-color: #10b981;
    --secondary-dark: #059669;
    --danger-color: #ef4444;
    --danger-dark: #dc2626;
    --warning-color: #f59e0b;
    --warning-dark: #d97706;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-light: #f8fafc;
    --bg-white: #ffffff;
    --text-dark: #1e293b;
    --text-medium: #475569;
    --text-light: #94a3b8;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
}

/* === GENERAL RESET === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* === BODY STYLING === */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-light);
    color: var(--text-dark);
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
}

/* === TYPOGRAPHY === */
h1, h2, h3, h4, h5, h6 {
    color: var(--text-dark);
    font-weight: 700;
    margin-bottom: 1rem;
}

h2 {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* === CONTAINER === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* === CARDS === */
.card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

/* === DASHBOARD GRID === */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem 0;
}

/* === DASHBOARD CARDS === */
.dashboard-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 2rem;
    text-align: center;
    border-radius: var(--radius-xl);
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 600;
    box-shadow: var(--shadow-lg);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 150px;
    position: relative;
    overflow: hidden;
}

.dashboard-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0) 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.dashboard-card:hover::before {
    opacity: 1;
}

.dashboard-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-xl);
}

/* Different colors for dashboard cards */
.dashboard-card:nth-child(1) {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.dashboard-card:nth-child(2) {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.dashboard-card:nth-child(3) {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

.dashboard-card:nth-child(4) {
    background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
}

.dashboard-card:nth-child(5) {
    background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}

.dashboard-card.danger {
    background: linear-gradient(135deg, #ff6b6b 0%, #c92a2a 100%);
}

/* === FORM STYLING === */
.form-container {
    max-width: 500px;
    margin: 2rem auto;
    background: var(--bg-white);
    padding: 2.5rem;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
}

form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

label {
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.25rem;
    display: block;
}

/* === INPUT FIELDS === */
input[type="text"],
input[type="password"],
input[type="number"],
input[type="email"],
input[type="tel"],
select,
textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-white);
    color: var(--text-dark);
    transition: all 0.3s ease;
    font-family: inherit;
}

input:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

input::placeholder {
    color: var(--text-light);
}

/* === CHECKBOX STYLING === */
input[type="checkbox"] {
    width: 1.25rem;
    height: 1.25rem;
    cursor: pointer;
    margin-right: 0.5rem;
}

/* === BUTTONS === */
button,
.btn {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

button[type="submit"],
.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    box-shadow: var(--shadow-md);
}

button[type="submit"]:hover,
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

button[type="submit"]:active,
.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background: var(--secondary-dark);
}

.btn-danger {
    background: var(--danger-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

.btn-danger:hover {
    background: var(--danger-dark);
}

.btn-warning {
    background: var(--warning-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

.btn-warning:hover {
    background: var(--warning-dark);
}

/* === LINKS === */
a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--primary-dark);
}

.back-link {
    display: inline-block;
    margin-top: 2rem;
    padding: 0.75rem 1.5rem;
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-dark);
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
}

.back-link:hover {
    background: var(--bg-light);
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateX(-4px);
}

/* === TABLES === */
.table-container {
    overflow-x: auto;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin: 2rem 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-white);
}

thead {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: white;
    text-transform: uppercase;
    font-size: 0.875rem;
    letter-spacing: 0.05em;
}

td {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-medium);
}

tr:last-child td {
    border-bottom: none;
}

tbody tr {
    transition: background-color 0.2s ease;
}

tbody tr:hover {
    background-color: var(--bg-light);
}

/* === ACTION BUTTONS IN TABLES === */
.edit-btn,
.delete-btn,
.call-btn {
    padding: 0.4rem 0.8rem;
    margin: 0 0.25rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    transition: all 0.2s ease;
}

.edit-btn {
    background: var(--warning-color);
    color: white;
}

.edit-btn:hover {
    background: var(--warning-dark);
    transform: scale(1.05);
}

.delete-btn {
    background: var(--danger-color);
    color: white;
}

.delete-btn:hover {
    background: var(--danger-dark);
    transform: scale(1.05);
}

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

.call-btn:hover {
    background: var(--primary-dark);
}

/* === MESSAGES === */
.success,
.error,
.info {
    padding: 1rem 1.5rem;
    border-radius: var(--radius-md);
    margin: 1rem 0;
    font-weight: 600;
    text-align: center;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.success {
    background: #d1fae5;
    color: #065f46;
    border: 2px solid #10b981;
}

.error {
    background: #fee2e2;
    color: #991b1b;
    border: 2px solid #ef4444;
}

.info {
    background: #dbeafe;
    color: #1e40af;
    border: 2px solid #3b82f6;
}

/* === FILTER FORM === */
.filter-form {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: flex-end;
    background: var(--bg-white);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: 2rem;
}

.filter-form input,
.filter-form select,
.filter-form button {
    flex: 1;
    min-width: 150px;
}

.filter-form button {
    flex: 0 0 auto;
}

/* === LOGIN PAGE === */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-box {
    background: var(--bg-white);
    padding: 3rem;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    max-width: 400px;
    width: 100%;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.login-box h2 {
    margin-bottom: 2rem;
    text-align: center;
}

/* === WELCOME HEADER === */
.welcome-header {
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: var(--radius-xl);
    margin-bottom: 2rem;
    box-shadow: var(--shadow-lg);
}

.welcome-header h2 {
    color: white;
    -webkit-text-fill-color: white;
    margin: 0;
    font-size: 2rem;
}

/* === RESPONSIVE DESIGN === */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    h2 {
        font-size: 1.5rem;
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .dashboard-card {
        min-height: 120px;
        padding: 1.5rem;
        font-size: 1rem;
    }

    .form-container {
        padding: 1.5rem;
    }

    .filter-form {
        flex-direction: column;
    }

    .filter-form input,
    .filter-form select,
    .filter-form button {
        width: 100%;
    }

    table {
        font-size: 0.875rem;
    }

    th, td {
        padding: 0.75rem 0.5rem;
    }

    .login-box {
        padding: 2rem 1.5rem;
        margin: 1rem;
    }
}

@media (max-width: 480px) {
    h2 {
        font-size: 1.25rem;
    }

    .dashboard-card {
        min-height: 100px;
        padding: 1rem;
        font-size: 0.9rem;
    }

    .form-container {
        padding: 1rem;
    }

    input,
    select,
    button {
        font-size: 0.9rem;
        padding: 0.6rem 0.8rem;
    }

    table {
        font-size: 0.75rem;
    }

    th, td {
        padding: 0.5rem 0.25rem;
    }
}

/* === UTILITY CLASSES === */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }
.p-3 { padding: 1.5rem; }
.p-4 { padding: 2rem; }

/* === LOADING ANIMATION === */
.spinner {
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 2rem auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}