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

:root {
    --primary-color: #1e3a8a;
    --secondary-color: #3b82f6;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --light-bg: #f8fafc;
    --border-color: #e2e8f0;
    --text-dark: #1e293b;
    --text-light: #64748b;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 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);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--light-bg);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2rem;
    border-radius: 10px;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-lg);
}

.header-content h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1rem;
    opacity: 0.9;
}

/* Navigation */
.navigation {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 2rem;
    background: white;
    padding: 1rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
}

.nav-btn {
    flex: 1;
    min-width: 150px;
    padding: 12px 20px;
    border: 2px solid var(--border-color);
    background: white;
    color: var(--text-dark);
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.nav-btn:hover {
    background: var(--light-bg);
    border-color: var(--secondary-color);
    transform: translateY(-2px);
}

.nav-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Form Sections */
.form-section {
    display: block;
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
}

.form-section.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

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

.form-section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--secondary-color);
}

/* Forms */
.data-form {
    max-width: 900px;
}

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

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

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

.required {
    color: var(--danger-color);
}

input[type="text"],
input[type="date"],
input[type="url"],
input[type="number"],
select,
textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
    font-family: inherit;
}

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

textarea {
    resize: vertical;
    min-height: 80px;
}

small {
    display: block;
    margin-top: 0.25rem;
    color: var(--text-light);
    font-size: 0.875rem;
}

/* Buttons */
.btn-submit {
    background: var(--primary-color);
    color: white;
    padding: 14px 32px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.btn-submit:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-submit:active {
    transform: translateY(0);
}

.btn-load {
    background: var(--secondary-color);
    color: white;
    padding: 10px 24px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
    margin-bottom: 1rem;
}

.btn-load:hover {
    background: var(--primary-color);
}

.btn-delete {
    background: var(--danger-color);
    color: white;
    padding: 6px 12px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.875rem;
    transition: all 0.3s ease;
}

.btn-delete:hover {
    background: #dc2626;
}

/* Data Display */
.data-category {
    margin-bottom: 2rem;
}

.data-category h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.data-display {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
    background: white;
    box-shadow: var(--shadow);
    border-radius: 8px;
    overflow: hidden;
}

.data-table th {
    background: var(--primary-color);
    color: white;
    padding: 12px;
    text-align: left;
    font-weight: 600;
    font-size: 0.9rem;
}

.data-table td {
    padding: 12px;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.9rem;
}

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

.data-table tr:hover {
    background: var(--light-bg);
}

.data-table img {
    max-width: 100px;
    max-height: 100px;
    border-radius: 4px;
}

/* Notification */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 16px 24px;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    transform: translateX(400px);
    transition: transform 0.3s ease;
    z-index: 1000;
    max-width: 400px;
}

.notification.show {
    transform: translateX(0);
}

.notification.success {
    background: var(--success-color);
}

.notification.error {
    background: var(--danger-color);
}

.notification.info {
    background: var(--secondary-color);
}

/* Loading Spinner */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-light);
}

.empty-state p {
    font-size: 1.1rem;
    margin-top: 1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    .header-content h1 {
        font-size: 1.5rem;
    }

    .navigation {
        flex-direction: column;
    }

    .nav-btn {
        min-width: 100%;
    }

    .form-section {
        padding: 1.5rem;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .data-table {
        font-size: 0.8rem;
    }

    .data-table th,
    .data-table td {
        padding: 8px;
    }

    .notification {
        left: 10px;
        right: 10px;
        max-width: calc(100% - 20px);
    }
}

/* Print Styles */
@media print {
    .navigation,
    .btn-submit,
    .btn-load,
    .btn-delete,
    .notification {
        display: none;
    }

    .form-section {
        box-shadow: none;
    }
}

/* Accessibility */
button:focus,
input:focus,
select:focus,
textarea:focus {
    outline: 2px solid var(--secondary-color);
    outline-offset: 2px;
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Selection Color */
::selection {
    background: var(--secondary-color);
    color: white;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--light-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-light);
}