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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #8b5cf6;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border: #334155;
    --success: #10b981;
    --error: #ef4444;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-lg: rgba(0, 0, 0, 0.5);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--background) 0%, #1a1f3a 100%);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 0;
    line-height: 1.6;
}

/* Top Header Bar */
.top-header-bar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(30, 41, 59, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 4px 24px var(--shadow);
    padding: 1rem 0;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.header-left {
    display: flex;
    align-items: center;
}

.app-title {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.75rem;
    font-weight: 700;
    margin: 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.title-icon {
    font-size: 1.5rem;
    filter: drop-shadow(0 2px 4px rgba(99, 102, 241, 0.3));
}

.title-text {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-right {
    display: flex;
    align-items: center;
    flex: 1;
    justify-content: flex-end;
    max-width: 400px;
    gap: 0.75rem;
}

.archive-toggle-wrapper {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    white-space: nowrap;
}

.toggle-label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color 0.3s ease;
    user-select: none;
}

.archive-toggle-wrapper.active .toggle-label {
    color: var(--text-primary);
    font-weight: 600;
}

.archive-toggle-wrapper:not(.active) .toggle-label {
    color: var(--text-secondary);
    font-weight: 500;
}

.archive-toggle {
    position: relative;
    width: 50px;
    height: 26px;
    background: var(--surface-light);
    border: 1px solid var(--border);
    border-radius: 13px;
    cursor: pointer;
    transition: all 0.3s ease;
    padding: 0;
    outline: none;
    flex-shrink: 0;
}

.archive-toggle:hover {
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.1);
}

.archive-toggle.active {
    background: var(--secondary-color);
    border-color: var(--secondary-color);
}

.archive-toggle.active:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
}

.toggle-slider {
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    background: white;
    border-radius: 50%;
    transition: transform 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.archive-toggle.active .toggle-slider {
    transform: translateX(24px);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

/* Top Section - Modern Unified Design */
.top-section {
    margin-bottom: 3rem;
    animation: fadeIn 0.6s ease-out;
}

.add-link-section {
    animation: fadeIn 0.8s ease-out;
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 400;
    margin: 0 0 1.5rem 0;
    opacity: 0.8;
}

/* Add Link Section */
.link-form {
    margin: 0;
}

.input-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: var(--surface);
    padding: 0.5rem 0.75rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    box-shadow: 0 4px 12px var(--shadow);
    transition: all 0.3s ease;
}

.input-wrapper:focus-within {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1), 0 4px 12px var(--shadow);
}

.input-icon {
    color: var(--text-muted);
    flex-shrink: 0;
    transition: color 0.3s ease;
}

.input-wrapper:focus-within .input-icon {
    color: var(--primary-color);
}

#linkInput {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 0.95rem;
    padding: 0.5rem 0;
    outline: none;
    font-weight: 400;
}

#linkInput::placeholder {
    color: var(--text-muted);
    font-weight: 400;
}

.btn-add {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 0.625rem 1.25rem;
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 70px;
    position: relative;
}

.btn-add:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(99, 102, 241, 0.4);
}

.btn-add:active:not(:disabled) {
    transform: translateY(0);
}

.btn-add:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-loader {
    display: none;
    align-items: center;
    justify-content: center;
}

.btn-loader svg {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* Search in Header */
.search-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    padding: 0.625rem 1rem;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
    width: 100%;
    min-width: 250px;
}

.search-wrapper:focus-within {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.search-icon {
    color: var(--text-muted);
    flex-shrink: 0;
    transition: color 0.3s ease;
}

.search-wrapper:focus-within .search-icon {
    color: var(--primary-color);
}

#searchInput {
    width: 100%;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 0.95rem;
    padding: 0;
    outline: none;
    font-weight: 400;
}

#searchInput::placeholder {
    color: var(--text-muted);
    font-weight: 400;
}

/* Toast Container */
.toast-container {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    pointer-events: none;
    align-items: flex-end;
}

.toast {
    padding: 0.875rem 1.25rem;
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 500;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(10px);
    opacity: 0;
    transform: translateX(400px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: auto;
    word-wrap: break-word;
    white-space: nowrap;
    width: fit-content;
    max-width: calc(100vw - 2rem);
}

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

.toast-success {
    background: rgba(16, 185, 129, 0.95);
    border: 1px solid var(--success);
    color: white;
}

.toast-error {
    background: rgba(239, 68, 68, 0.95);
    border: 1px solid var(--error);
    color: white;
}

.links-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
    animation: fadeIn 1s ease-out;
}

.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.link-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    overflow: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px var(--shadow);
    display: flex;
    flex-direction: column;
    animation: fadeInUp 0.5s ease-out;
}

.link-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 16px var(--shadow-lg);
    border-color: var(--primary-color);
}

.link-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--surface-light);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.link-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.link-content {
    padding: 1.5rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.link-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.link-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1rem;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.5;
}

.link-url {
    color: var(--primary-color);
    font-size: 0.85rem;
    text-decoration: none;
    margin-bottom: 1rem;
    word-break: break-all;
    transition: color 0.3s ease;
}

.link-url:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.link-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.link-actions {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.link-date {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.archive-btn {
    background: rgba(139, 92, 246, 0.2);
    color: var(--secondary-color);
    border: 1px solid var(--secondary-color);
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

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

.delete-btn {
    background: rgba(239, 68, 68, 0.2);
    color: var(--error);
    border: 1px solid var(--error);
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

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

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

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

@media (max-width: 768px) {
    .toast-container {
        top: 0.75rem;
        right: 0.75rem;
        left: 0.75rem;
        align-items: flex-end;
    }

    .toast {
        white-space: normal;
        max-width: 100%;
    }

    .top-header-bar {
        padding: 0.75rem 0;
    }

    .header-container {
        display: grid;
        grid-template-columns: 1fr auto;
        grid-template-rows: auto auto;
        gap: 0.75rem;
        align-items: center;
    }

    .header-left {
        grid-column: 1;
        grid-row: 1;
        justify-content: flex-start;
    }

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

    .title-icon {
        font-size: 1.25rem;
    }

    .header-right {
        display: contents;
    }

    .archive-toggle-wrapper {
        grid-column: 2;
        grid-row: 1;
        flex-shrink: 0;
    }

    .search-wrapper {
        grid-column: 1 / -1;
        grid-row: 2;
        width: 100%;
    }

    .link-actions {
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .archive-btn,
    .delete-btn {
        flex: 1;
        min-width: 80px;
    }

    .input-wrapper {
        flex-wrap: wrap;
    }

    .btn-add {
        width: 100%;
        padding: 0.75rem 1.25rem;
    }

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

/* Scroll to Top Button */
.scroll-to-top-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
    transition: all 0.3s ease;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 999;
}

.scroll-to-top-btn.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.scroll-to-top-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(99, 102, 241, 0.5);
}

.scroll-to-top-btn:active {
    transform: translateY(-1px);
}

.scroll-to-top-btn svg {
    width: 24px;
    height: 24px;
}

@media (max-width: 400px) {
    .header-right {
        flex-direction: column;
        gap: 0.75rem;
    }

    .search-wrapper {
        min-width: 100%;
    }

    .archive-toggle-wrapper {
        width: 100%;
        justify-content: flex-start;
    }

    .scroll-to-top-btn {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 45px;
        height: 45px;
    }
}