/* CSS Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --twitter-color: #000000;
    --facebook-color: #1877f2;
    --linkedin-color: #0a66c2;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8f0 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    text-align: center;
    padding: 40px 0 30px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.logo-icon {
    width: 40px;
    height: 40px;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

/* Main Content */
.main-content {
    flex: 1;
    padding-bottom: 40px;
}

/* URL Input Section */
.url-input-section {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: 32px;
    box-shadow: var(--shadow-lg);
    margin-bottom: 24px;
}

.input-wrapper {
    display: flex;
    gap: 12px;
}

#url-input {
    flex: 1;
    padding: 14px 18px;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
    font-family: var(--font-family);
}

#url-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

#url-input::placeholder {
    color: var(--text-muted);
}

.btn-primary {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    min-width: 120px;
}

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

.btn-primary:active {
    transform: scale(0.98);
}

.btn-primary:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

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

.spinner {
    width: 20px;
    height: 20px;
    animation: spin 1s linear infinite;
}

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

.input-hint {
    margin-top: 12px;
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Error Message */
.error-message {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: var(--error-color);
    padding: 16px 20px;
    border-radius: var(--radius-md);
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.error-message::before {
    content: "!";
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: var(--error-color);
    color: white;
    border-radius: 50%;
    font-weight: 700;
    font-size: 0.875rem;
    flex-shrink: 0;
}

/* Results Section */
.results-section {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

/* Tabs */
.tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.tab {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 16px 20px;
    background: none;
    border: none;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color 0.2s, background 0.2s;
    position: relative;
}

.tab svg {
    width: 18px;
    height: 18px;
}

.tab:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.tab.active {
    color: var(--primary-color);
    background: var(--bg-primary);
}

.tab.active::after {
    content: "";
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

/* Tab Content */
.tab-content {
    padding: 24px;
}

.tab-panel {
    display: none;
}

.tab-panel.active {
    display: block;
}

/* Previews Grid */
.previews-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 24px;
}

/* Preview Cards */
.preview-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.preview-header {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 18px;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
    font-size: 0.9375rem;
}

.platform-icon {
    width: 20px;
    height: 20px;
}

.platform-icon.twitter { color: var(--twitter-color); }
.platform-icon.facebook { color: var(--facebook-color); }
.platform-icon.linkedin { color: var(--linkedin-color); }

/* Twitter Preview */
.twitter-preview {
    padding: 16px;
}

.twitter-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.twitter-image-container {
    position: relative;
    width: 100%;
    height: 160px;
    background: var(--bg-tertiary);
    overflow: hidden;
}

.twitter-image-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: none;
}

.twitter-image-container img.loaded {
    display: block;
}

.twitter-image-placeholder,
.facebook-image-placeholder,
.linkedin-image-placeholder {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.twitter-image-container img.loaded + .twitter-image-placeholder,
.facebook-image-container img.loaded + .facebook-image-placeholder,
.linkedin-image-container img.loaded + .linkedin-image-placeholder {
    display: none;
}

.twitter-content {
    padding: 12px 14px;
}

.twitter-title {
    font-weight: 600;
    font-size: 0.9375rem;
    color: var(--text-primary);
    margin-bottom: 4px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.twitter-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.twitter-url {
    font-size: 0.8125rem;
    color: var(--text-muted);
}

/* Facebook Preview */
.facebook-preview {
    padding: 16px;
}

.facebook-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.facebook-image-container {
    position: relative;
    width: 100%;
    height: 160px;
    background: var(--bg-tertiary);
    overflow: hidden;
}

.facebook-image-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: none;
}

.facebook-image-container img.loaded {
    display: block;
}

.facebook-content {
    padding: 12px 14px;
    background: var(--bg-secondary);
}

.facebook-url {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-bottom: 4px;
}

.facebook-title {
    font-weight: 600;
    font-size: 0.9375rem;
    color: var(--text-primary);
    margin-bottom: 4px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.facebook-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* LinkedIn Preview */
.linkedin-preview {
    padding: 16px;
}

.linkedin-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.linkedin-image-container {
    position: relative;
    width: 100%;
    height: 160px;
    background: var(--bg-tertiary);
    overflow: hidden;
}

.linkedin-image-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: none;
}

.linkedin-image-container img.loaded {
    display: block;
}

.linkedin-content {
    padding: 12px 14px;
}

.linkedin-title {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-primary);
    margin-bottom: 4px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.linkedin-url {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Share Section */
.share-section {
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.share-section h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.share-section p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: 16px;
}

.share-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.share-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.1s;
    border: none;
}

.share-btn:hover {
    opacity: 0.9;
}

.share-btn:active {
    transform: scale(0.98);
}

.share-btn svg {
    width: 18px;
    height: 18px;
}

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

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

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

.share-btn.copy {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

/* Tags List */
.tags-container h3,
.suggestions-container h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.tags-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.tag-item {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.tag-name {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--primary-color);
    font-family: 'SF Mono', 'Fira Code', monospace;
}

.tag-value {
    font-size: 0.9375rem;
    color: var(--text-primary);
    word-break: break-all;
}

.tag-missing {
    color: var(--text-muted);
    font-style: italic;
}

/* Suggestions List */
.suggestions-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.suggestion-item {
    display: flex;
    gap: 14px;
    padding: 16px;
    border-radius: var(--radius-md);
    border: 1px solid;
}

.suggestion-item.success {
    background: #f0fdf4;
    border-color: #bbf7d0;
}

.suggestion-item.warning {
    background: #fffbeb;
    border-color: #fde68a;
}

.suggestion-item.error {
    background: #fef2f2;
    border-color: #fecaca;
}

.suggestion-icon {
    flex-shrink: 0;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
}

.suggestion-item.success .suggestion-icon {
    background: var(--success-color);
    color: white;
}

.suggestion-item.warning .suggestion-icon {
    background: var(--warning-color);
    color: white;
}

.suggestion-item.error .suggestion-icon {
    background: var(--error-color);
    color: white;
}

.suggestion-content {
    flex: 1;
}

.suggestion-title {
    font-weight: 600;
    font-size: 0.9375rem;
    margin-bottom: 4px;
}

.suggestion-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Footer */
.footer {
    text-align: center;
    padding: 24px 0;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.footer p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Hidden utility */
[hidden] {
    display: none !important;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: 30px 0 20px;
    }

    .logo h1 {
        font-size: 1.5rem;
    }

    .logo-icon {
        width: 32px;
        height: 32px;
    }

    .url-input-section {
        padding: 20px;
    }

    .input-wrapper {
        flex-direction: column;
    }

    .btn-primary {
        width: 100%;
    }

    .tabs {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .tab {
        padding: 14px 16px;
        white-space: nowrap;
        font-size: 0.875rem;
    }

    .tab span {
        display: none;
    }

    .tab svg {
        width: 20px;
        height: 20px;
    }

    .tab-content {
        padding: 16px;
    }

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

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

    .share-btn {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .app-container {
        padding: 0 12px;
    }

    .header {
        padding: 20px 0 16px;
    }

    .logo h1 {
        font-size: 1.25rem;
    }

    .tagline {
        font-size: 0.875rem;
    }

    .url-input-section {
        padding: 16px;
        border-radius: var(--radius-lg);
    }

    #url-input {
        padding: 12px 14px;
        font-size: 0.9375rem;
    }

    .btn-primary {
        padding: 12px 20px;
    }

    .results-section {
        border-radius: var(--radius-lg);
    }

    .preview-card {
        border-radius: var(--radius-md);
    }

    .tag-item,
    .suggestion-item {
        padding: 12px;
    }
}

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

.results-section:not([hidden]) {
    animation: fadeIn 0.3s ease-out;
}

/* Toast notification for copy */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-primary);
    color: white;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    animation: toastIn 0.3s ease-out;
}

@keyframes toastIn {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}