/* ===== CSS Variables ===== */
:root {
    --primary-color: #2196F3;
    --primary-light: #64B5F6;
    --primary-dark: #1976D2;
    --primary-50: #E3F2FD;
    --primary-100: #BBDEFB;
    --secondary-color: #03A9F4;
    --accent-color: #00BCD4;
    --background-color: #F5F9FC;
    --card-background: #FFFFFF;
    --text-primary: #1A237E;
    --text-secondary: #546E7A;
    --text-light: #78909C;
    --border-color: #E1E8ED;
    --success-color: #4CAF50;
    --warning-color: #FF9800;
    --danger-color: #F44336;
    --shadow-sm: 0 2px 4px rgba(33, 150, 243, 0.1);
    --shadow-md: 0 4px 12px rgba(33, 150, 243, 0.15);
    --shadow-lg: 0 8px 24px rgba(33, 150, 243, 0.2);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: all 0.3s ease;
}

/* ===== Reset & Base ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--background-color) 0%, var(--primary-50) 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

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

/* ===== Header ===== */
.header {
    text-align: center;
    padding: 40px 20px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: var(--radius-lg);
    margin-bottom: 30px;
    box-shadow: var(--shadow-lg);
    color: white;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 10px;
}

.logo i {
    font-size: 2.5rem;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.logo h1 {
    font-size: 2.2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* ===== Add Link Section ===== */
.add-link-section {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.add-link-section h2 {
    color: var(--primary-dark);
    margin-bottom: 25px;
    font-size: 1.4rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.link-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--background-color);
    color: var(--text-primary);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px var(--primary-50);
    background: white;
}

.form-group textarea {
    resize: vertical;
    min-height: 60px;
}

/* ===== Buttons ===== */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--background-color);
    color: var(--text-secondary);
    border: 2px solid var(--border-color);
}

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

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

.btn-danger:hover {
    background: #D32F2F;
}

/* ===== Filter Section ===== */
.filter-section {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.search-box {
    position: relative;
    margin-bottom: 15px;
}

.search-box i {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-light);
}

.search-box input {
    width: 100%;
    padding: 14px 16px 14px 45px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--background-color);
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px var(--primary-50);
    background: white;
}

.filter-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.filter-btn {
    padding: 8px 16px;
    border: 2px solid var(--border-color);
    border-radius: 50px;
    background: white;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.filter-btn:hover {
    border-color: var(--primary-light);
    color: var(--primary-color);
}

.filter-btn.active {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    border-color: transparent;
}

/* ===== Links Section ===== */
.links-section {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 30px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    min-height: 300px;
}

.links-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--primary-50);
}

.links-header h2 {
    color: var(--primary-dark);
    font-size: 1.4rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.link-count {
    background: var(--primary-50);
    color: var(--primary-dark);
    padding: 6px 14px;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 600;
}

.links-grid {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

/* ===== Category Section ===== */
.category-section {
    background: var(--background-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.category-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    cursor: pointer;
}

.category-title {
    display: flex;
    align-items: center;
    gap: 12px;
}

.category-title i {
    font-size: 1.3rem;
    width: 36px;
    height: 36px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.category-title h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin: 0;
}

.category-count {
    background: rgba(255, 255, 255, 0.25);
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
}

.category-toggle {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.category-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
}

.category-links {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 15px;
    padding: 20px;
    transition: var(--transition);
}

.category-links.collapsed {
    display: none;
}

/* ===== Link Card ===== */
.link-card {
    background: linear-gradient(135deg, white 0%, var(--primary-50) 100%);
    border-radius: var(--radius-md);
    padding: 20px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.link-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary-color) 0%, var(--accent-color) 100%);
}

.link-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.link-card-header {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    margin-bottom: 12px;
}

.link-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
    flex-shrink: 0;
}

.link-info {
    flex: 1;
    min-width: 0;
}

.link-name {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 1.1rem;
    margin-bottom: 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.link-url {
    color: var(--primary-color);
    font-size: 0.85rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: block;
}

.link-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 12px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.link-category {
    display: inline-block;
    background: var(--primary-100);
    color: var(--primary-dark);
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: 15px;
}

.link-actions {
    display: flex;
    gap: 10px;
    padding-top: 12px;
    border-top: 1px solid var(--border-color);
}

.link-actions button {
    flex: 1;
    padding: 8px 12px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

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

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

.btn-edit {
    background: var(--primary-50);
    color: var(--primary-dark);
}

.btn-edit:hover {
    background: var(--primary-100);
}

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

.btn-delete:hover {
    background: #FFCDD2;
}

.btn-copy {
    background: var(--primary-50);
    color: var(--primary-dark);
}

.btn-copy:hover {
    background: var(--primary-100);
}

/* ===== Empty State ===== */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-light);
    display: none;
}

.empty-state.show {
    display: block;
}

.empty-state i {
    font-size: 4rem;
    color: var(--primary-light);
    margin-bottom: 20px;
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 1.4rem;
    color: var(--text-secondary);
    margin-bottom: 10px;
}

/* ===== Modal ===== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
    backdrop-filter: blur(4px);
}

.modal.show {
    display: flex;
}

.modal-content {
    background: white;
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease;
}

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

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 25px;
    border-bottom: 1px solid var(--border-color);
    background: var(--primary-50);
}

.modal-header h3 {
    color: var(--primary-dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

.close-btn {
    width: 36px;
    height: 36px;
    border: none;
    background: white;
    border-radius: 50%;
    font-size: 1.5rem;
    color: var(--text-light);
    cursor: pointer;
    transition: var(--transition);
}

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

#editForm {
    padding: 25px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.modal-actions {
    display: flex;
    gap: 15px;
    margin-top: 10px;
}

.modal-actions button {
    flex: 1;
}

/* ===== Toast ===== */
.toast {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--success-color);
    color: white;
    padding: 15px 25px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 10px;
    transform: translateY(100px);
    opacity: 0;
    transition: var(--transition);
    z-index: 1001;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

.toast i {
    font-size: 1.2rem;
}

/* ===== Footer ===== */
.footer {
    text-align: center;
    padding: 30px;
    color: var(--text-light);
    margin-top: 30px;
}

.footer i {
    color: var(--danger-color);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    .header {
        padding: 30px 15px;
    }

    .logo h1 {
        font-size: 1.6rem;
    }

    .logo i {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 0.95rem;
    }

    .add-link-section,
    .links-section {
        padding: 20px;
    }

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

    .filter-buttons {
        justify-content: center;
    }

    .links-grid {
        grid-template-columns: 1fr;
    }

    .links-header {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }

    .link-actions {
        flex-wrap: wrap;
    }

    .link-actions button {
        min-width: calc(50% - 5px);
    }

    .toast {
        left: 20px;
        right: 20px;
        bottom: 20px;
    }
}

/* ===== Category Colors ===== */
/* ===== Scrollbar ===== */
::-webkit-scrollbar {
    width: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--primary-light);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

/* ===== Loading State ===== */
.loading-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--primary-color);
}

.loading-state i {
    font-size: 3rem;
    margin-bottom: 15px;
    display: block;
}

.loading-state p {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* ===== Connection Status ===== */
.connection-status {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 10px 20px;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 500;
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 8px;
}

.connection-status.online {
    background: #E8F5E9;
    color: var(--success-color);
}

.connection-status.offline {
    background: #FFEBEE;
    color: var(--danger-color);
}