/* Simple Library Management System */

:root {
    /* Primary Colors */
    --primary-blue: #2563eb;
    --primary-blue-dark: #1e40af;
    --primary-blue-light: #3b82f6;
    
    /* Neutral Colors */
    --white: #ffffff;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-900: #111827;
    
    /* Semantic Colors */
    --success: #10b981;
    --success-light: #d1fae5;
    --error: #ef4444;
    --error-light: #fee2e2;
    --warning: #f59e0b;
    --warning-light: #fef3c7;
    --info: #3b82f6;
    --info-light: #dbeafe;
    
    /* Light mode (default) */
    --bg-color: var(--white);
    --bg-secondary: var(--gray-50);
    --text-color: var(--gray-900);
    --text-secondary: var(--gray-600);
    --card-bg: var(--white);
    --border-color: var(--gray-200);
    --input-bg: var(--white);
    --hover-bg: var(--gray-100);
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --bg-secondary: #1e293b;
    --text-color: #f1f5f9;
    --text-secondary: #cbd5e1;
    --card-bg: #1e293b;
    --border-color: #334155;
    --input-bg: #1e293b;
    --hover-bg: #334155;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    font-size: 16px;
}

/* Header & Navigation */
header {
    background: var(--primary-blue);
    color: var(--white);
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-menu-link {
    color: var(--white);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
}

.user-menu-link:hover {
    background-color: rgba(255, 255, 255, 0.2);
}

nav .logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--white);
    text-decoration: none;
}

nav .logo:hover {
    opacity: 0.9;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    align-items: center;
}

nav ul li a {
    color: var(--white);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 0;
}

nav ul li a:hover {
    opacity: 0.8;
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

/* Page Content Wrapper */
.page-content {
    padding: 2rem 0;
    min-height: calc(100vh - 200px);
}

.page-header {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.page-header h1 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.page-header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    text-decoration: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    line-height: 1.5;
}

.btn:hover {
    opacity: 0.9;
}

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

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

.btn-secondary {
    background-color: var(--gray-600);
    color: var(--white);
}

.btn-secondary:hover {
    background-color: var(--gray-700);
}

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

.btn-danger:hover {
    background-color: #dc2626;
}

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

.btn-success:hover {
    background-color: #059669;
}

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

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

/* Cards */
.card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.card-header {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--primary-blue);
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

/* Grid */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
    padding: 0;
}

/* Forms */
.form-group {
    margin-bottom: 1.75rem;
}

.search-form {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: 4px;
    margin-bottom: 2rem;
}

.search-form .form-group {
    margin-bottom: 0;
    display: flex;
    gap: 1rem;
    align-items: flex-end;
}

.search-form input {
    flex: 1;
    max-width: 600px;
}

.search-form button {
    white-space: nowrap;
}

.form-group label {
    display: block;
    margin-bottom: 0.75rem;
    font-weight: 600;
    color: var(--text-color);
    font-size: 0.95rem;
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"],
.form-group input[type="date"],
.form-group input[type="file"],
.form-group input[type="number"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    background-color: var(--input-bg);
    color: var(--text-color);
    font-family: inherit;
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-blue);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--gray-400);
}

/* Messages */
.messages {
    margin: 1.5rem 0;
}

.message {
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.message.success {
    background-color: var(--success-light);
    color: #065f46;
    border: 1px solid var(--success);
}

.message.error {
    background-color: var(--error-light);
    color: #991b1b;
    border: 1px solid var(--error);
}

.message.info {
    background-color: var(--info-light);
    color: #1e40af;
    border: 1px solid var(--info);
}

.message.warning {
    background-color: var(--warning-light);
    color: #92400e;
    border: 1px solid var(--warning);
}

/* Library/Book/Author Cards */
.library-card,
.book-card,
.author-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.library-card:hover,
.book-card:hover,
.author-card:hover {
    border-color: var(--primary-blue);
}

.library-card img,
.book-card img,
.author-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
}

.library-card-content,
.book-card-content,
.author-card-content {
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.library-card-content h3,
.book-card-content h3,
.author-card-content h3 {
    color: var(--primary-blue);
    margin-bottom: 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
}

.library-card-content h3 a,
.book-card-content h3 a,
.author-card-content h3 a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: color 0.3s ease;
}

.library-card-content h3 a:hover,
.book-card-content h3 a:hover,
.author-card-content h3 a:hover {
    color: var(--primary-blue-dark);
    text-decoration: underline;
}

.library-card-content p,
.book-card-content p,
.author-card-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 0.875rem;
    flex-grow: 1;
}

.library-card-content small,
.book-card-content small,
.author-card-content small {
    color: var(--gray-500);
    font-size: 0.875rem;
    display: block;
    margin-bottom: 0.5rem;
}

/* Footer */
footer {
    background: var(--primary-blue-dark);
    color: var(--white);
    margin-top: 3rem;
    padding: 2rem 0;
}

footer a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    transition: all 0.3s ease;
}

footer a:hover {
    color: var(--white);
    text-decoration: underline;
}

/* Utilities */
.text-center {
    text-align: center;
}

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

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

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-5 { margin-bottom: 3rem; }

.flex {
    display: flex;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.flex-center {
    display: flex;
    justify-content: center;
    align-items: center;
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: 5rem 2rem;
    color: var(--text-color);
}

.empty-state h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.empty-state p {
    font-size: 1.125rem;
    margin-top: 1rem;
    color: var(--text-secondary);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--white);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.mobile-menu-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Theme Toggle Button */
.theme-toggle {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--white);
    border-radius: 4px;
    padding: 0.5rem;
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
}

.theme-toggle-icon {
    font-size: 1.2rem;
    line-height: 1;
}

/* Pagination */
.pagination-wrapper {
    margin: 3rem 0 2rem;
}

.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.pagination-btn {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    text-decoration: none;
    color: var(--primary-blue);
    background: var(--card-bg);
    font-size: 0.9rem;
    font-weight: 500;
    min-width: 40px;
    text-align: center;
}

.pagination-btn:hover:not(.disabled):not(.active) {
    background-color: var(--primary-blue);
    color: var(--white);
    border-color: var(--primary-blue);
}

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

.pagination-btn.disabled {
    color: var(--gray-400);
    background: var(--bg-secondary);
    border-color: var(--border-color);
    cursor: not-allowed;
    opacity: 0.5;
}

.pagination-info {
    text-align: center;
    margin-top: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Badge */
.badge {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.875rem;
    font-weight: 500;
    background-color: var(--primary-blue);
    color: var(--white);
}

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

.badge-warning {
    background-color: var(--warning);
}

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

/* Responsive */
@media (max-width: 768px) {
    /* Navigation */
    nav {
        flex-wrap: wrap;
        position: relative;
        padding: 1rem;
    }
    
    .header-right {
        gap: 0.5rem;
    }
    
    .user-menu-link {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    nav ul {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: 0.5rem;
        margin-top: 1rem;
        padding-top: 1rem;
        border-top: 1px solid rgba(255, 255, 255, 0.2);
    }
    
    nav ul.active {
        display: flex;
    }
    
    nav ul li {
        width: 100%;
    }
    
    nav ul li a {
        display: block;
        padding: 0.875rem;
        border-radius: 8px;
        transition: background-color 0.3s;
    }
    
    nav ul li a:hover {
        background-color: rgba(255, 255, 255, 0.1);
    }
    
    nav ul li a::after {
        display: none;
    }
    
    /* Container and Layout */
    .container {
        padding: 1rem;
    }
    
    .page-content {
        padding: 1rem 0;
    }
    
    .page-header {
        margin-bottom: 2rem;
    }
    
    .page-header h1 {
        font-size: 2rem;
        line-height: 1.3;
    }
    
    .page-header p {
        font-size: 1rem;
    }
    
    /* Grid */
    .grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        margin: 1.5rem 0;
    }
    
    /* Cards */
    .card {
        padding: 1.5rem;
        margin-bottom: 1.5rem;
    }
    
    .library-card-content,
    .book-card-content,
    .author-card-content {
        padding: 1.25rem;
    }
    
    .library-card-content h3,
    .book-card-content h3,
    .author-card-content h3 {
        font-size: 1.25rem;
    }
    
    /* Forms */
    .search-form {
        padding: 1.5rem;
        margin-bottom: 2rem;
    }
    
    .search-form .form-group {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
    
    .search-form input {
        max-width: 100%;
        width: 100%;
    }
    
    .search-form button {
        width: 100%;
    }
    
    .form-group {
        margin-bottom: 1.5rem;
    }
    
    /* Buttons */
    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.95rem;
        width: 100%;
        display: block;
    }
    
    .flex-between {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .flex {
        flex-wrap: wrap;
    }
    
    /* Footer */
    footer > div {
        padding: 2rem 1rem !important;
    }
    
    footer > div > div:first-child {
        grid-template-columns: 1fr !important;
        gap: 2rem !important;
    }
    
    /* Images */
    .library-card img,
    .book-card img,
    .author-card img {
        height: 200px;
    }
}

/* Small Mobile Devices */
@media (max-width: 480px) {
    nav {
        padding: 0.75rem;
    }
    
    nav .logo {
        font-size: 1.5rem;
    }
    
    .container {
        padding: 0.75rem;
    }
    
    .page-header h1 {
        font-size: 1.75rem;
    }
    
    .card {
        padding: 1.25rem;
    }
    
    .library-card-content,
    .book-card-content,
    .author-card-content {
        padding: 1rem;
    }
    
    .btn {
        padding: 0.625rem 1.25rem;
        font-size: 0.9rem;
    }
    
    .search-form {
        padding: 1.25rem;
    }
    
    .library-card img,
    .book-card img,
    .author-card img {
        height: 180px;
    }
    
    .pagination {
        gap: 0.25rem;
    }
    
    .pagination-btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.85rem;
        min-width: 36px;
    }
    
    .pagination-info {
        font-size: 0.85rem;
    }
}

/* Tablet */
@media (min-width: 769px) and (max-width: 1024px) {
    .grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.75rem;
    }
    
    .container {
        padding: 1.5rem;
    }
    
    nav ul {
        gap: 1.5rem;
    }
}

/* Large Screens */
@media (min-width: 1400px) {
    .container {
        max-width: 1600px;
    }
    
    nav {
        max-width: 1600px;
    }
}

/* Refresh/Loading Indicator */
.refresh-indicator {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 10000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    pointer-events: none;
}

.refresh-indicator.active {
    opacity: 1;
    visibility: visible;
    pointer-events: all;
}

.refresh-spinner {
    position: relative;
    width: 80px;
    height: 80px;
    margin-bottom: 1rem;
}

.spinner-ring {
    position: absolute;
    width: 100%;
    height: 100%;
    border: 4px solid transparent;
    border-top-color: var(--primary-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.spinner-ring:nth-child(1) {
    animation-delay: 0s;
    border-top-color: var(--primary-blue);
}

.spinner-ring:nth-child(2) {
    animation-delay: 0.15s;
    border-top-color: var(--primary-blue-light);
    width: 70%;
    height: 70%;
    top: 15%;
    left: 15%;
}

.spinner-ring:nth-child(3) {
    animation-delay: 0.3s;
    border-top-color: var(--primary-blue-dark);
    width: 50%;
    height: 50%;
    top: 25%;
    left: 25%;
}

.spinner-ring:nth-child(4) {
    animation-delay: 0.45s;
    border-top-color: var(--primary-blue);
    width: 30%;
    height: 30%;
    top: 35%;
    left: 35%;
}

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

.refresh-text {
    color: var(--white);
    font-size: 1.125rem;
    font-weight: 500;
    text-align: center;
    margin-top: 1rem;
    animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.6;
    }
}

[data-theme="dark"] .refresh-indicator {
    background: rgba(0, 0, 0, 0.7);
}

/* Mobile adjustments for refresh indicator */
@media (max-width: 768px) {
    .refresh-spinner {
        width: 60px;
        height: 60px;
    }
    
    .refresh-text {
        font-size: 1rem;
    }
}