/* Modern Design System - Theme tokens */
:root {
    --bg: #f8fafc;
    --text: #0f172a;
    --muted: #64748b;
    --muted-text: #64748b;

    --header-bg: #1e293b;
    --header-text: #f1f5f9;

    --card-bg: #ffffff;
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
    --card-shadow-hover: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);

    --code-bg: #f1f5f9;

    --btn-bg: #f8fafc;
    --btn-text: #334155;
    --btn-hover-bg: #e2e8f0;

    --action-bg: #f8fafc;
    --action-bg-hover: #e2e8f0;
    --action-text: #334155;
    --btn-border: #e2e8f0;
    --divider: #e2e8f0;

    /* Brand colors */
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --primary-light: #dbeafe;
    
    --success: #10b981;
    --success-hover: #059669;
    --success-light: #d1fae5;
    
    --warning: #f59e0b;
    --warning-hover: #d97706;
    --warning-light: #fef3c7;
    
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --danger-light: #fee2e2;

    /* Modern spacing and typography */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
    --spacing-xl: 1.5rem;
    --spacing-2xl: 2rem;

    /* header-specific tokens (header background is dark in both themes) */
    --header-btn-bg: rgba(255, 255, 255, 0.1);
    --header-btn-hover-bg: rgba(255, 255, 255, 0.2);
    --header-btn-border: rgba(255, 255, 255, 0.2);
    --header-divider: rgba(255, 255, 255, 0.2);
}

[data-theme="dark"] {
    --bg: #0f172a;
    --text: #f1f5f9;
    --muted: #94a3b8;
    --muted-text: #94a3b8;

    --header-bg: #020617;
    --header-text: #f1f5f9;

    --card-bg: #1e293b;
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.2);
    --card-shadow-hover: 0 4px 6px rgba(0, 0, 0, 0.3), 0 2px 4px rgba(0, 0, 0, 0.2);

    --code-bg: #334155;

    --btn-bg: #334155;
    --btn-text: #f1f5f9;
    --btn-hover-bg: #475569;

    --action-bg: #334155;
    --action-bg-hover: #475569;
    --action-text: #f1f5f9;
    --btn-border: #475569;
    --divider: #475569;

    /* Brand colors for dark theme */
    --primary: #60a5fa;
    --primary-hover: #3b82f6;
    --primary-light: #1e3a8a;
    
    --success: #34d399;
    --success-hover: #10b981;
    --success-light: #064e3b;
    
    --warning: #fbbf24;
    --warning-hover: #f59e0b;
    --warning-light: #451a03;
    
    --danger: #f87171;
    --danger-hover: #ef4444;
    --danger-light: #450a0a;

    /* keep header tokens appropriate for dark headers */
    --header-btn-bg: rgba(255, 255, 255, 0.1);
    --header-btn-hover-bg: rgba(255, 255, 255, 0.2);
    --header-btn-border: rgba(255, 255, 255, 0.2);
    --header-divider: rgba(255, 255, 255, 0.2);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text);
}

header {
    background: var(--header-bg);
    color: var(--header-text);
    padding: 1rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: nowrap;
    min-height: 60px;
    overflow: hidden;
    width: 100%;
    box-sizing: border-box;
    position: relative;
}

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    background: var(--header-btn-bg);
    border: 1px solid var(--header-btn-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s ease;
    padding: 0;
    gap: 4px;
}

/* Ensure mobile menu button is hidden on desktop */
@media (min-width: 769px) {
    .mobile-menu-btn {
        display: none !important;
    }
}

.mobile-menu-btn:hover {
    background: var(--header-btn-hover-bg);
}

.hamburger-line {
    width: 20px;
    height: 2px;
    background: var(--header-text);
    border-radius: 1px;
    transition: all 0.3s ease;
}

.mobile-menu-btn.active .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* Mobile Navigation Overlay */
.mobile-nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 9998;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.mobile-nav-overlay.active {
    opacity: 1;
    visibility: visible;
}

.mobile-nav-content {
    position: absolute;
    top: 0;
    right: 0;
    width: 280px;
    height: 100%;
    background: var(--card-bg);
    box-shadow: -4px 0 12px rgba(0, 0, 0, 0.15);
    transform: translateX(100%);
    transition: transform 0.3s ease;
    overflow-y: auto;
}

.mobile-nav-overlay.active .mobile-nav-content {
    transform: translateX(0);
}

.mobile-nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--divider);
    background: var(--header-bg);
    color: var(--header-text);
}

.mobile-nav-header h2 {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 600;
}

.mobile-nav-close {
    width: 32px;
    height: 32px;
    background: none;
    border: none;
    color: var(--header-text);
    font-size: 1.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    transition: background 0.2s ease;
}

.mobile-nav-close:hover {
    background: var(--header-btn-hover-bg);
}

.mobile-nav-body {
    padding: var(--spacing-lg);
    box-sizing: border-box;
    overflow-x: hidden;
}

.mobile-nav-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-xs);
    border-radius: var(--radius-md);
    text-decoration: none;
    color: var(--text);
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
    background: none;
    width: 100%;
    text-align: left;
}

.mobile-nav-item:hover {
    background: var(--action-bg-hover);
    transform: translateX(4px);
}

.mobile-nav-item .nav-icon {
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.mobile-nav-item .nav-text {
    font-size: 0.95rem;
    font-weight: 500;
}

.mobile-nav-btn {
    background: var(--action-bg);
    border: 1px solid var(--btn-border);
}

.mobile-nav-btn:hover {
    background: var(--action-bg-hover);
    border-color: var(--btn-border);
}

.mobile-logout-btn {
    background: var(--danger-light);
    color: var(--danger-hover);
    border-color: var(--danger);
}

.mobile-logout-btn:hover {
    background: var(--danger);
    color: white;
    border-color: var(--danger);
}

.mobile-user-info {
    background: var(--primary-light);
    color: var(--primary);
    border: 1px solid var(--primary);
    cursor: default;
}

.mobile-user-info:hover {
    background: var(--primary-light);
    transform: none;
}

.mobile-nav-divider {
    height: 1px;
    background: var(--divider);
    margin: var(--spacing-lg) 0;
}

.mobile-login-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.mobile-login-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: var(--spacing-xs);
    border-radius: var(--radius-md);
    background: var(--action-bg);
    border: 1px solid var(--btn-border);
    transition: all 0.2s ease;
    width: 100%;
    box-sizing: border-box;
}

.mobile-login-item .nav-icon {
    font-size: 1.2rem;
    width: 20px;
    text-align: center;
    flex-shrink: 0;
}

.mobile-login-input {
    flex: 1;
    padding: var(--spacing-xs) var(--spacing-sm);
    border: none;
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text);
    font-size: 0.9rem;
    min-width: 0;
    outline: none;
    box-sizing: border-box;
}

.mobile-login-input:focus {
    outline: none;
    background: var(--bg);
    box-shadow: inset 0 0 0 2px var(--primary);
    transform: scale(1.01);
    transition: all 0.2s ease;
}

/* Highlight mobile login section when focused */
.mobile-login-item:has(.mobile-login-input:focus) {
    background: var(--primary-light);
    border: 2px solid var(--primary);
    transform: translateX(2px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.2);
}

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

.mobile-login-btn:hover {
    background: var(--success-hover);
    border-color: var(--success-hover);
}

/* Mobile Responsive Header */
@media (max-width: 768px) {
    header {
        padding: var(--spacing-md) var(--spacing-lg);
        min-height: 60px;
        gap: var(--spacing-sm);
    }
    
    header h1 {
        font-size: 1rem;
        flex: 1;
        min-width: 0;
    }
    
    .desktop-nav,
    .page-header-right.desktop-nav {
        display: none !important;
    }
    
    .mobile-menu-btn {
        display: flex;
        flex-shrink: 0;
    }
    
    .header-left {
        flex: 1;
        min-width: 0;
    }
}

@media (max-width: 480px) {
    header {
        padding: var(--spacing-sm) var(--spacing-md);
        min-height: 56px;
    }
    
    header h1 {
        font-size: 0.9rem;
    }
    
    .mobile-nav-content {
        width: 100%;
    }
    
    .mobile-nav-item {
        padding: var(--spacing-lg);
    }
    
    .mobile-nav-item .nav-text {
        font-size: 1rem;
    }
}

header h1 {
    margin: 0;
    font-size: 1.25rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 100%;
}

header a {
    color: var(--header-text);
    text-decoration: none;
    font-weight: 600;
}


.header-left {
    flex: 1;
    min-width: 0;
    flex-shrink: 1;
}

.header-right {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: var(--spacing-xs);
}

header h1 {
    margin: 0;
    font-size: 1.3rem;
    font-weight: 700;
}

header h1 a {
    color: var(--header-text);
    text-decoration: none;
    font-weight: 700;
    transition: color 0.2s ease;
}

header h1 a:hover {
    color: var(--primary-light);
}


/* Navigation Buttons */
.nav-btn {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--header-btn-bg);
    color: var(--header-text);
    border: 1px solid var(--header-btn-border);
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
    flex-shrink: 0;
}

.nav-btn:hover {
    background: var(--header-btn-hover-bg);
    transform: translateY(-1px);
}

.nav-btn:active {
    transform: translateY(0);
}

.nav-icon {
    font-size: 0.9rem;
}

.nav-text {
    font-size: 0.85rem;
}

/* User Chip */
.user-chip {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--header-btn-bg);
    color: var(--header-text);
    border: 1px solid var(--header-btn-border);
    border-radius: var(--radius-md);
    font-size: 0.85rem;
    font-weight: 500;
}

.user-icon {
    font-size: 0.9rem;
}

.user-name {
    font-weight: 600;
}

/* Login Form */
.login-form {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    flex-shrink: 0;
}

.login-input {
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 1px solid var(--header-btn-border);
    border-radius: var(--radius-sm);
    background: var(--header-btn-bg);
    color: var(--header-text);
    font-size: 0.7rem;
    min-width: 80px;
    flex-shrink: 0;
}

.login-input::placeholder {
    color: var(--muted-text);
}

.login-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

/* Theme Button */
.theme-btn {
    width: 28px;
    height: 28px;
    padding: 0;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    background: var(--header-btn-bg);
    color: var(--header-text);
    border: 1px solid var(--header-btn-border);
    cursor: pointer;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.theme-btn:hover {
    background: var(--header-btn-hover-bg);
    transform: scale(1.05);
}

/* Admin Button */
.admin-btn {
    background: var(--warning);
    color: white;
    border-color: var(--warning);
}

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

/* Logout Button */
.logout-btn {
    background: var(--danger);
    color: white;
    border-color: var(--danger);
}

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

main {
    max-width: 980px;
    margin: auto;
    padding: 2rem 1rem 4rem;
}

/* Article Cards - Match existing site design */

/* Modern Article Header */
.article-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--divider);
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex: 1;
}

.document-icon {
    font-size: 1.2rem;
    opacity: 0.7;
}

.article-header h2 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin: 0;
    font-size: 1.25rem;
    font-weight: 700;
    line-height: 1.3;
}

.article-header h2 a {
    color: var(--text);
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 700;
    transition: color 0.2s ease;
}

.article-header h2 a:hover {
    color: var(--primary);
}

.page-header-right {
    display: flex;
    flex-direction: row;
    align-items: flex-end;
    gap: var(--spacing-xs);
}

.source-badge .user-chip {
    background: var(--primary-light);
    color: var(--primary);
    border: 1px solid var(--primary);
    font-weight: 500;
    font-size: 0.8rem;
}

.update-time {
    font-size: 0.75rem;
    color: var(--muted-text);
    font-weight: 500;
}

/* Content Section */
.content-section {
    margin: var(--spacing-lg) 0;
}

.section-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    margin: 0 0 var(--spacing-sm) 0;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.section-title.collapsible {
    cursor: pointer;
    user-select: none;
    transition: color 0.2s ease;
}

.section-title.collapsible:hover {
    color: var(--primary);
}

.chevron {
    font-size: 0.8rem;
    transition: transform 0.2s ease;
}

.section-title.collapsible.expanded .chevron {
    transform: rotate(90deg);
}

.summary-section {
    margin-bottom: var(--spacing-lg);
}

.placeholder-text {
    color: var(--muted-text);
    font-style: italic;
    font-size: 0.9rem;
    margin: var(--spacing-sm) 0;
}

/* Action Button Layout */
.card-actions {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--divider);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.primary-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.secondary-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.primary-btn {
    background: var(--primary) !important;
    color: white !important;
    border-color: var(--primary) !important;
    font-weight: 600 !important;
    padding: var(--spacing-sm) var(--spacing-lg) !important;
}

.primary-btn:hover {
    background: var(--primary-hover) !important;
    border-color: var(--primary-hover) !important;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3) !important;
}

.secondary-btn {
    background: var(--action-bg) !important;
    color: var(--action-text) !important;
    border-color: var(--btn-border) !important;
    font-size: 0.8rem !important;
    padding: var(--spacing-xs) var(--spacing-sm) !important;
    opacity: 0.8;
    transition: all 0.2s ease;
}

.secondary-btn:hover {
    opacity: 1;
    background: var(--action-bg-hover) !important;
    transform: translateY(-1px);
}

/* Modern Tag Pills */
.tag-row { 
    display: flex; 
    flex-wrap: wrap; 
    gap: var(--spacing-sm); 
    margin: var(--spacing-md) 0; 
}

.tag-chip {
    display: inline-flex; 
    align-items: center; 
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm); 
    border-radius: 999px; 
    font-size: 0.8rem;
    font-weight: 500;
    background: var(--primary-light); 
    color: var(--primary); 
    text-decoration: none;
    border: 1px solid var(--primary);
    transition: all 0.2s ease;
}

.tag-chip:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(59, 130, 246, 0.3);
}

.tag-chip.active { 
    background: var(--primary);
    color: white;
    box-shadow: 0 0 0 2px var(--primary-light);
}

.tag-chip.query-hit { 
    background: var(--warning-light); 
    border-color: var(--warning); 
    color: var(--warning-hover);
    box-shadow: 0 0 0 2px var(--warning-light);
}

/* Top chips styling */
.top-chip { 
    display: inline-flex; 
    align-items: center; 
    gap: var(--spacing-xs); 
    padding: var(--spacing-xs) var(--spacing-sm); 
    border-radius: 999px; 
    font-size: 0.8rem; 
    font-weight: 600;
    background: var(--success-light); 
    color: var(--success-hover); 
    border: 1px solid var(--success);
    text-decoration: none;
    margin-right: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    transition: all 0.2s ease;
}

.top-chip:hover {
    background: var(--success);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(16, 185, 129, 0.3);
}

/* Favorite star styling */
.favorite-star {
    font-size: 1.1rem;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.8; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.1); }
}

.favorite-star-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
    transition: all 0.2s ease;
    color: var(--muted);
}

.favorite-star-btn:hover {
    background: var(--action-bg-hover);
    color: #fbbf24;
    transform: scale(1.1);
}

.favorite-star-btn svg {
    transition: all 0.2s ease;
}

.favorite-star-btn:hover svg {
    fill: #fbbf24;
}

/* Modern Article Cards */
article {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--card-shadow);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    position: relative;
    border: 1px solid var(--btn-border);
    transition: all 0.2s ease;
}

article:hover {
    box-shadow: var(--card-shadow-hover);
    transform: translateY(-1px);
}

article h2 {
    margin: 0 0 0.5rem 0;
    font-size: 1.35rem;
}

.preview-html {
    transition: max-height 0.2s ease-in-out;
    overflow: hidden;
}

.preview-html.collapsed {
    max-height: 20rem;
}

.toggle-link {
    cursor: pointer;
    font-size: 0.9rem;
    user-select: none;
}

.card-actions {
    margin-top: 0.75rem;
    font-size: 0.9rem;
    color: var(--muted);
}

.card-actions a {
    margin-right: 0.75rem;
    cursor: pointer;
}

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

.markdown-body {
    line-height: 1.65;
}

pre {
    overflow: auto;
    background: var(--code-bg);
    padding: 1rem;
    border-radius: 6px;
}

code {
    background: var(--code-bg);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-size: 87%;
}

.topbar-btn {
    padding: 0.25rem 0.7rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    background: var(--btn-bg);
    color: var(--btn-text);
    font-size: 0.85rem;
    text-decoration: none;
    display: inline-block;
    border: 1px solid var(--btn-border);
}

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

.topbar-btn:focus-visible {
    outline: 2px solid #60a5fa;
    outline-offset: 2px;
}

.icon-btn {
    width: 2rem;
    height: 2rem;
    padding: 0;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
}

.topbar-group {
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.topbar-divider {
    width: 1px;
    height: 1.5rem;
    background: var(--divider);
    margin: 0 0.2rem;
}

.user-chip {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--header-btn-bg);
    color: var(--header-text);
    border: 1px solid var(--header-btn-border);
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    font-weight: 500;
    flex-shrink: 0;
    white-space: nowrap;
}

/* Modern Action Buttons */
.card-actions {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--divider);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.action-btn,
.card-actions a {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    margin-right: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    background: var(--action-bg);
    color: var(--action-text);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-size: 0.85rem;
    font-weight: 500;
    border: 1px solid var(--btn-border);
    cursor: pointer;
    transition: all 0.15s ease;
    position: relative;
    overflow: hidden;
}

.action-btn:hover,
.card-actions a:hover {
    background: var(--action-bg-hover);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.action-btn:active,
.card-actions a:active {
    transform: translateY(0);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

/* Primary Action - Open PDF */
.action-btn[href*="arxiv.org/pdf"],
.card-actions a[href*="arxiv.org/pdf"] {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    font-weight: 600;
}

.action-btn[href*="arxiv.org/pdf"]:hover,
.card-actions a[href*="arxiv.org/pdf"]:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

/* Secondary Actions - Mark as Read */
.mark-read-link {
    background: var(--success);
    color: white;
    border-color: var(--success);
}

.mark-read-link:hover {
    background: var(--success-hover);
    border-color: var(--success-hover);
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}

/* Secondary Actions - Favorite */
.favorite-link {
    background: var(--warning);
    color: white;
    border-color: var(--warning);
}

.favorite-link:hover {
    background: var(--warning-hover);
    border-color: var(--warning-hover);
    box-shadow: 0 2px 8px rgba(245, 158, 11, 0.3);
}

.favorite-link[data-favorited="true"] {
    background: var(--danger);
    border-color: var(--danger);
}

.favorite-link[data-favorited="true"]:hover {
    background: var(--danger-hover);
    border-color: var(--danger-hover);
    box-shadow: 0 2px 8px rgba(239, 68, 68, 0.3);
}

/* Secondary Actions - Remove buttons */
.remove-read-link,
.remove-favorite-link {
    background: var(--muted);
    color: white;
    border-color: var(--muted);
}

.remove-read-link:hover,
.remove-favorite-link:hover {
    background: var(--text);
    border-color: var(--text);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

/* Star icon in paper titles */
.article-header h2 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 0 0.5rem 0;
}

.favorite-star {
    font-size: 1rem;
    opacity: 0.9;
    animation: starGlow 2s ease-in-out infinite alternate;
}

@keyframes starGlow {
    from { opacity: 0.8; transform: scale(1); }
    to { opacity: 1; transform: scale(1.05); }
}

.favorite-star-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    color: var(--muted);
    opacity: 0.6;
}

.favorite-star-btn:hover {
    background: rgba(251, 191, 36, 0.1);
    color: #fbbf24;
    opacity: 1;
    transform: scale(1.1);
}

.favorite-star-btn:active {
    transform: scale(0.95);
}

.favorite-star-btn[data-favorited="true"] {
    color: #fbbf24;
    opacity: 1;
}

.favorite-star-btn[data-favorited="true"] svg {
    fill: #fbbf24;
}

.favorite-star-btn svg {
    transition: fill 0.2s ease;
}

/* Enhanced article header */
.article-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.75rem;
    gap: 1rem;
}

.article-header h2 a {
    color: var(--text);
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 600;
}

.article-header h2 a:hover {
    color: #60a5fa;
}

/* Modern Paper Metadata */
.paper-metadata {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--code-bg);
    border-radius: var(--radius-md);
    border: 1px solid var(--btn-border);
    font-size: 0.8rem;
}

.metadata-row {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    align-items: center;
    justify-content: flex-end;
}

.metadata-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    background: var(--card-bg);
    border: 1px solid var(--btn-border);
    min-width: 0;
    flex-shrink: 0;
}

.metadata-icon {
    font-size: 0.8rem;
    flex-shrink: 0;
    opacity: 0.7;
}

.metadata-content {
    display: flex;
    flex-direction: column;
    gap: 0.05rem;
    min-width: 0;
}

.metadata-label {
    font-size: 0.6rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    opacity: 0.6;
    line-height: 1;
}

.metadata-value {
    font-size: 0.7rem;
    font-weight: 500;
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', monospace;
    line-height: 1.2;
    color: var(--muted-text);
}

/* Specific styling for different metadata types */
.metadata-item.updated {
    border-color: rgba(100, 116, 139, 0.3);
}

.metadata-item.updated .metadata-label {
    color: var(--muted);
}

.metadata-item.read {
    border-color: rgba(16, 185, 129, 0.3);
    background: var(--success-light);
}

.metadata-item.read .metadata-label {
    color: var(--success-hover);
}

.metadata-item.favorite {
    border-color: rgba(245, 158, 11, 0.3);
    background: var(--warning-light);
}

.metadata-item.favorite .metadata-label {
    color: var(--warning-hover);
}

/* Dark theme adjustments */
[data-theme="dark"] .metadata-item.read {
    background: rgba(5, 150, 105, 0.1);
}

[data-theme="dark"] .metadata-item.favorite {
    background: rgba(245, 158, 11, 0.1);
}

/* Mobile responsive metadata */
@media (max-width: 768px) {
    .paper-metadata {
        margin-top: 0.5rem;
        padding: 0.4rem 0.6rem;
    }
    
    .metadata-row {
        gap: 0.5rem;
    }
    
    .metadata-item {
        padding: 0.2rem 0.4rem;
        gap: 0.3rem;
    }
    
    .metadata-icon {
        font-size: 0.8rem;
    }
    
    .metadata-label {
        font-size: 0.6rem;
    }
    
    .metadata-value {
        font-size: 0.7rem;
    }
}

/* Extra small screens - stack metadata items */
@media (max-width: 480px) {
    .metadata-row {
        flex-direction: column;
        align-items: stretch;
        gap: 0.4rem;
    }
    
    .metadata-item {
        justify-content: center;
    }
}

/* 🔔 toast notification */
#toast {
    position: fixed;
    top: 1rem;
    right: 1rem;
    max-width: 280px;
    padding: .75rem 1rem;
    border-radius: .5rem;
    background: #1f2937;
    /* dark slate */
    color: #fff;
    font-size: .9rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, .15);
    opacity: 0;
    transform: translateY(-20px);
    pointer-events: none;
    /* clicks pass through */
    transition: opacity .3s ease, transform .3s ease;
    z-index: 9999;
}

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

/* Abstract Section Styles */
.abstract-section {
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-lg);
    background: var(--code-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--btn-border);
}

.abstract-heading {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
}

.abstract-icon {
    font-size: 1.1rem;
    opacity: 0.8;
}

.abstract-text {
    line-height: 1.6;
    color: var(--text);
    font-size: 0.95rem;
    margin: 0;
    padding: 0;
}

.abstract-loading {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--muted-text);
    font-style: italic;
}

.abstract-loading-icon {
    animation: spin 1s linear infinite;
}

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

.abstract-error {
    color: var(--danger);
    font-style: italic;
}

.abstract-fetch-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--primary);
    color: white;
    border: 1px solid var(--primary);
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
}

.abstract-fetch-btn:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.abstract-fetch-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}