:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --success-color: #059669;
    --danger-color: #dc2626;
    --warning-color: #f59e0b;
    --light-bg: #f8fafc;
    --dark-bg: #0f172a;
    --border-color: #e2e8f0;
    --text-dark: #1e293b;
    --text-light: #64748b;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.15);
}

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

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

/* Navbar Styles */
.navbar-custom {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    box-shadow: var(--shadow);
    padding: 1rem 0;
}

.brand-text {
    font-size: 1.8rem;
    font-weight: 700;
    color: white !important;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    letter-spacing: -0.5px;
}

.navbar-nav .nav-link {
    color: rgba(255, 255, 255, 0.85) !important;
    font-weight: 500;
    transition: all 0.3s ease;
    margin: 0 0.5rem;
}

.navbar-nav .nav-link:hover,
.navbar-nav .nav-link.active {
    color: white !important;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 6px;
    padding: 0.5rem 1rem;
}

.btn-login {
    background: rgba(255, 255, 255, 0.2) !important;
    border: 2px solid white !important;
    color: white !important;
    padding: 0.5rem 1.5rem !important;
}

.btn-login:hover {
    background: white !important;
    color: var(--primary-color) !important;
}

/* Hero Section */
.hero-section {
    position: relative;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 8rem 0;
    overflow: hidden;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg width="60" height="60" viewBox="0 0 60 60" xmlns="http://www.w3.org/2000/svg"><g fill="none" fill-rule="evenodd"><g fill="%23ffffff" fill-opacity="0.1"><path d="M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z"/></g></g></svg>');
    opacity: 0.1;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-icon {
    font-size: 8rem;
    opacity: 0.2;
}

/* Features Section */
.features-section {
    padding: 5rem 0;
    background: white;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-dark);
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.feature-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

/* Page Header */
.page-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 3rem 0;
    margin-bottom: 2rem;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
}

.page-header p {
    font-size: 1.1rem;
    opacity: 0.95;
}

/* Books Section */
.books-section {
    padding: 2rem 0;
    min-height: 80vh;
}

.search-group {
    box-shadow: var(--shadow);
    border-radius: 8px;
    overflow: hidden;
}

.search-group input {
    border: 1px solid var(--border-color);
    padding: 0.75rem 1rem;
}

.search-group input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.search-group button {
    border: none;
    padding: 0.75rem 1.5rem;
}

.book-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
    height: 100%;
}

.book-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.book-image {
    width: 100%;
    height: 250px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: white;
}

.book-content {
    padding: 1.5rem;
}

.book-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.book-author {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 0.75rem;
}

.book-details {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

.book-details span {
    display: block;
    margin-bottom: 0.5rem;
}

.book-actions {
    display: flex;
    gap: 0.5rem;
}

.book-actions button {
    flex: 1;
    padding: 0.5rem;
    font-size: 0.85rem;
}

/* Members Section */
.members-section {
    padding: 2rem 0;
    min-height: 80vh;
}

.members-table {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.members-table thead {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
}

.members-table thead th {
    border: none;
    padding: 1.25rem;
    font-weight: 600;
}

.members-table tbody tr {
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.members-table tbody tr:hover {
    background-color: rgba(37, 99, 235, 0.05);
}

.members-table tbody td {
    padding: 1rem 1.25rem;
    vertical-align: middle;
}

.status-badge {
    display: inline-block;
    padding: 0.4rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.status-active {
    background: rgba(5, 150, 105, 0.1);
    color: var(--success-color);
}

.status-inactive {
    background: rgba(220, 38, 38, 0.1);
    color: var(--danger-color);
}

/* Loans Section */
.loans-section {
    padding: 2rem 0;
    min-height: 80vh;
}

.filter-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.loans-table {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.loans-table thead {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
}

.loans-table thead th {
    border: none;
    padding: 1.25rem;
    font-weight: 600;
}

.loans-table tbody tr {
    border-bottom: 1px solid var(--border-color);
}

.loans-table tbody tr:hover {
    background-color: rgba(37, 99, 235, 0.05);
}

.loans-table tbody td {
    padding: 1rem 1.25rem;
    vertical-align: middle;
}

.status-pending {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
}

.status-returned {
    background: rgba(5, 150, 105, 0.1);
    color: var(--success-color);
}

.status-overdue {
    background: rgba(220, 38, 38, 0.1);
    color: var(--danger-color);
}

/* Login Page */
.login-body {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.login-container {
    width: 100%;
    max-width: 420px;
    padding: 1rem;
}

.login-card {
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    padding: 2rem;
}

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

.login-header i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.login-header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.login-header p {
    color: var(--text-light);
    font-size: 0.95rem;
}

#loginForm .form-label {
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

#loginForm .form-control {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    transition: all 0.3s ease;
}

#loginForm .form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

#loginForm .btn-primary {
    padding: 0.75rem;
    font-weight: 600;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border: none;
    transition: all 0.3s ease;
}

#loginForm .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 12px rgba(37, 99, 235, 0.3);
}

.login-footer {
    text-align: center;
    margin-top: 1.5rem;
}

.back-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.back-link:hover {
    color: var(--secondary-color);
    transform: translateX(-3px);
}

/* Footer */
.footer {
    background: linear-gradient(135deg, var(--text-dark) 0%, #1a1f35 100%);
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 3rem;
}

.footer h5 {
    font-weight: 700;
    margin-bottom: 1rem;
}

.footer-links {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: all 0.3s ease;
}

.footer-links a:hover {
    color: white;
    padding-left: 5px;
}

.footer-divider {
    border-color: rgba(255, 255, 255, 0.1);
    margin: 2rem 0 1rem;
}

/* Buttons */
.btn {
    padding: 0.6rem 1.5rem;
    font-weight: 600;
    border-radius: 6px;
    transition: all 0.3s ease;
    border: none;
}

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

.btn-primary:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(37, 99, 235, 0.3);
}

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

.btn-success:hover {
    background: #047857;
    transform: translateY(-2px);
}

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

.btn-danger:hover {
    background: #b91c1c;
}

.btn-outline-primary {
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    background: transparent;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .hero-buttons .btn {
        width: 100%;
    }

    .page-header h1 {
        font-size: 1.8rem;
    }

    .section-title {
        font-size: 1.8rem;
    }

    .hero-icon {
        font-size: 4rem;
    }

    .search-group {
        margin-bottom: 1rem;
    }

    .feature-card {
        margin-bottom: 1rem;
    }

    .table-responsive {
        font-size: 0.85rem;
    }

    .login-card {
        padding: 1.5rem;
    }

    .navbar-nav .nav-link {
        margin: 0.25rem 0;
        border-radius: 6px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 0.95rem;
    }

    .page-header {
        padding: 1.5rem 0;
    }

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

    .section-title {
        font-size: 1.5rem;
    }

    .brand-text {
        font-size: 1.4rem;
    }
}

/* Animation */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.book-card,
.feature-card {
    animation: slideIn 0.5s ease-out;
}

/* Utilities */
.d-none {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-end {
    text-align: right;
}

.mb-4 {
    margin-bottom: 1.5rem;
}

.mt-3 {
    margin-top: 1rem;
}