:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: #1a1a24;
    --bg-card-hover: #22222e;
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    --border-color: #27272a;
    --border-hover: #3f3f46;
    
    --accent-foundations: #6366f1;
    --accent-language: #8b5cf6;
    --accent-multimodal: #ec4899;
    --accent-efficiency: #f59e0b;
    --accent-data: #10b981;
    
    --card-glow: rgba(99, 102, 241, 0.15);
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.app {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 24px;
}

.header {
    padding: 40px 0 32px;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 32px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 24px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 16px;
}

.logo-icon {
    font-size: 48px;
    filter: drop-shadow(0 0 20px rgba(99, 102, 241, 0.5));
}

.logo-text h1 {
    font-size: 28px;
    font-weight: 700;
    background: linear-gradient(135deg, #f5f5f7 0%, #a1a1aa 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-muted);
    font-size: 14px;
    margin-top: 4px;
}

.stats {
    display: flex;
    align-items: center;
    gap: 20px;
    background: var(--bg-secondary);
    padding: 16px 24px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-value {
    font-size: 28px;
    font-weight: 700;
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

.stat-label {
    font-size: 12px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--border-color);
}

.progress-ring {
    position: relative;
    width: 60px;
    height: 60px;
}

.progress-ring svg {
    transform: rotate(-90deg);
    width: 100%;
    height: 100%;
}

.progress-ring-bg {
    fill: none;
    stroke: var(--border-color);
    stroke-width: 3;
}

.progress-ring-fill {
    fill: none;
    stroke: url(#progress-gradient);
    stroke: var(--accent-foundations);
    stroke-width: 3;
    stroke-linecap: round;
    transition: stroke-dasharray var(--transition-slow);
}

.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 12px;
    font-weight: 600;
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-secondary);
}

.tabs {
    display: flex;
    gap: 8px;
    padding: 8px;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    margin-bottom: 32px;
    overflow-x: auto;
    scrollbar-width: none;
}

.tabs::-webkit-scrollbar {
    display: none;
}

.tab {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: transparent;
    border: none;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

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

.tab.active {
    background: var(--bg-card);
    color: var(--text-primary);
    box-shadow: 0 0 0 1px var(--border-hover);
}

.tab-icon {
    font-size: 18px;
}

.tab-count {
    background: var(--border-color);
    padding: 2px 8px;
    border-radius: 20px;
    font-size: 12px;
    font-family: 'JetBrains Mono', monospace;
}

.tab.active .tab-count {
    background: var(--accent-foundations);
    color: white;
}

.bento-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
    padding-bottom: 60px;
}

.paper-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 24px;
    cursor: pointer;
    transition: all var(--transition-normal);
    overflow: hidden;
}

.paper-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--card-accent, var(--accent-foundations));
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.paper-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.paper-card:hover::before {
    opacity: 1;
}

.paper-card.unread {
    filter: grayscale(0.7);
    opacity: 0.5;
}

.paper-card.unread:hover {
    filter: grayscale(0.3);
    opacity: 0.75;
}

.paper-card.read {
    border-color: var(--card-accent);
    box-shadow: 
        0 0 0 1px var(--card-accent),
        0 0 20px color-mix(in srgb, var(--card-accent) 25%, transparent),
        inset 0 1px 0 color-mix(in srgb, var(--card-accent) 10%, transparent);
}

.paper-card.read::before {
    opacity: 1;
    height: 4px;
}

.paper-card.read::after {
    content: '✓';
    position: absolute;
    top: 16px;
    right: 16px;
    width: 28px;
    height: 28px;
    background: var(--card-accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
    color: white;
    box-shadow: 0 4px 12px color-mix(in srgb, var(--card-accent) 50%, transparent);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 16px;
}

.card-category {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    font-size: 12px;
    color: var(--text-secondary);
}

.card-category-icon {
    font-size: 14px;
}

.card-year {
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
    color: var(--text-muted);
    background: rgba(255, 255, 255, 0.03);
    padding: 4px 10px;
    border-radius: var(--radius-sm);
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 12px;
    color: var(--text-primary);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-authors {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 16px;
    display: -webkit-box;
    -webkit-line-clamp: 1;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-significance {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 16px;
}

.tag {
    font-size: 11px;
    padding: 4px 10px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    color: var(--text-muted);
}

.modal {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal.open {
    opacity: 1;
    visibility: visible;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(8px);
}

.modal-content {
    position: relative;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 32px;
    max-width: 700px;
    width: 100%;
    max-height: 85vh;
    overflow-y: auto;
    transform: translateY(20px) scale(0.95);
    transition: transform var(--transition-normal);
}

.modal.open .modal-content {
    transform: translateY(0) scale(1);
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    border: none;
    background: var(--bg-card);
    border-radius: 50%;
    font-size: 24px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}

.modal-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.modal-category {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    background: rgba(99, 102, 241, 0.15);
    border-radius: 20px;
    font-size: 13px;
    color: var(--accent-foundations);
    font-weight: 500;
}

.modal-year {
    font-family: 'JetBrains Mono', monospace;
    font-size: 14px;
    color: var(--text-muted);
}

.modal-title {
    font-size: 24px;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 12px;
}

.modal-authors {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 20px;
}

.modal-significance {
    color: var(--text-primary);
    font-size: 15px;
    line-height: 1.6;
    padding: 16px;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--accent-foundations);
    margin-bottom: 20px;
}

.modal-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 24px;
}

.modal-tags .tag {
    font-size: 12px;
    padding: 6px 14px;
}

.modal-notes {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-bottom: 24px;
}

.modal-notes h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.notes-content {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
}

.notes-content.has-notes {
    color: var(--text-primary);
}

.notes-content a {
    color: #60a5fa;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.notes-content a:hover {
    color: #93c5fd;
}

.no-notes {
    color: var(--text-muted);
    font-style: italic;
}

.no-notes code {
    background: var(--bg-secondary);
    padding: 2px 8px;
    border-radius: 4px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    color: var(--accent-foundations);
}

.modal-actions {
    display: flex;
    gap: 12px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 24px;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
}

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

.btn-primary:hover {
    background: #5558e3;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-card);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

.footer {
    text-align: center;
    padding: 40px 0;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 14px;
}

.footer p {
    margin-bottom: 8px;
}

.footer .source-credit {
    font-size: 12px;
    color: var(--text-muted);
    opacity: 0.8;
}

.footer a {
    color: var(--accent-foundations);
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

.paper-card[data-category="foundations"] { --card-accent: var(--accent-foundations); }
.paper-card[data-category="language-models"] { --card-accent: var(--accent-language); }
.paper-card[data-category="multimodal"] { --card-accent: var(--accent-multimodal); }
.paper-card[data-category="efficiency"] { --card-accent: var(--accent-efficiency); }
.paper-card[data-category="data"] { --card-accent: var(--accent-data); }

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

.paper-card {
    animation: fadeIn 0.4s ease forwards;
}

.paper-card:nth-child(1) { animation-delay: 0.05s; }
.paper-card:nth-child(2) { animation-delay: 0.1s; }
.paper-card:nth-child(3) { animation-delay: 0.15s; }
.paper-card:nth-child(4) { animation-delay: 0.2s; }
.paper-card:nth-child(5) { animation-delay: 0.25s; }
.paper-card:nth-child(6) { animation-delay: 0.3s; }
.paper-card:nth-child(7) { animation-delay: 0.35s; }
.paper-card:nth-child(8) { animation-delay: 0.4s; }
.paper-card:nth-child(9) { animation-delay: 0.45s; }
.paper-card:nth-child(10) { animation-delay: 0.5s; }

/* Tablet and small desktop */
@media (max-width: 768px) {
    .app {
        padding: 0 16px;
        padding-left: max(16px, env(safe-area-inset-left));
        padding-right: max(16px, env(safe-area-inset-right));
    }
    
    .header {
        padding: 24px 0;
        padding-top: max(24px, env(safe-area-inset-top));
    }
    
    .header-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 16px;
    }
    
    .logo-icon {
        font-size: 36px;
    }
    
    .logo-text h1 {
        font-size: 22px;
    }
    
    .stats {
        width: 100%;
        justify-content: center;
        padding: 14px 20px;
        gap: 16px;
    }
    
    .stat-value {
        font-size: 24px;
    }
    
    .progress-ring {
        width: 50px;
        height: 50px;
    }
    
    .tabs {
        padding: 6px;
        margin-bottom: 24px;
        gap: 4px;
    }
    
    .tab {
        padding: 12px 16px;
        font-size: 13px;
        min-height: 44px; /* Touch target */
    }
    
    .tab-text {
        display: none;
    }
    
    .tab-icon {
        font-size: 20px;
    }
    
    .tab-count {
        font-size: 11px;
        padding: 2px 6px;
    }
    
    .bento-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .paper-card {
        padding: 20px;
    }
    
    .card-title {
        font-size: 15px;
    }
    
    .modal {
        padding: 0;
    }
    
    .modal-content {
        padding: 24px;
        padding-bottom: max(24px, env(safe-area-inset-bottom));
        margin: 0;
        max-height: 100vh;
        height: 100%;
        border-radius: 0;
        border: none;
    }
    
    .modal-close {
        width: 44px;
        height: 44px;
        top: max(16px, env(safe-area-inset-top));
        right: 16px;
    }
    
    .modal-title {
        font-size: 20px;
        padding-right: 50px;
    }
    
    .modal-actions {
        flex-direction: column;
        position: sticky;
        bottom: 0;
        background: var(--bg-secondary);
        margin: 0 -24px -24px;
        padding: 16px 24px;
        padding-bottom: max(16px, env(safe-area-inset-bottom));
        border-top: 1px solid var(--border-color);
    }
    
    .btn {
        justify-content: center;
        min-height: 48px;
    }
    
    .footer {
        padding-bottom: max(40px, env(safe-area-inset-bottom));
    }
}

/* Small phones (iPhone SE, etc.) */
@media (max-width: 480px) {
    .app {
        padding: 0 12px;
        padding-left: max(12px, env(safe-area-inset-left));
        padding-right: max(12px, env(safe-area-inset-right));
    }
    
    .header {
        padding: 16px 0;
        padding-top: max(16px, env(safe-area-inset-top));
        margin-bottom: 16px;
    }
    
    .logo {
        gap: 12px;
    }
    
    .logo-icon {
        font-size: 32px;
    }
    
    .logo-text h1 {
        font-size: 18px;
    }
    
    .tagline {
        font-size: 12px;
    }
    
    .stats {
        padding: 12px 16px;
        gap: 12px;
    }
    
    .stat-value {
        font-size: 20px;
    }
    
    .stat-label {
        font-size: 10px;
    }
    
    .stat-divider {
        height: 32px;
    }
    
    .progress-ring {
        width: 44px;
        height: 44px;
    }
    
    .progress-text {
        font-size: 10px;
    }
    
    .tabs {
        padding: 4px;
        margin-bottom: 16px;
        gap: 2px;
    }
    
    .tab {
        padding: 10px 12px;
        min-height: 44px;
    }
    
    .tab-icon {
        font-size: 18px;
    }
    
    .tab-count {
        display: none;
    }
    
    .bento-grid {
        gap: 12px;
    }
    
    .paper-card {
        padding: 16px;
    }
    
    .card-header {
        margin-bottom: 12px;
    }
    
    .card-category {
        padding: 4px 10px;
        font-size: 11px;
    }
    
    .card-year {
        font-size: 12px;
        padding: 3px 8px;
    }
    
    .card-title {
        font-size: 14px;
        margin-bottom: 8px;
        -webkit-line-clamp: 2;
    }
    
    .card-authors {
        font-size: 12px;
        margin-bottom: 10px;
    }
    
    .card-significance {
        font-size: 12px;
    }
    
    .card-tags {
        margin-top: 12px;
        gap: 6px;
    }
    
    .tag {
        font-size: 10px;
        padding: 3px 8px;
    }
    
    .paper-card.read::after {
        width: 24px;
        height: 24px;
        font-size: 12px;
        top: 12px;
        right: 12px;
    }
    
    .modal-content {
        padding: 20px;
        padding-top: max(60px, calc(env(safe-area-inset-top) + 50px));
    }
    
    .modal-header {
        gap: 8px;
        margin-bottom: 12px;
    }
    
    .modal-category {
        padding: 5px 12px;
        font-size: 12px;
    }
    
    .modal-year {
        font-size: 13px;
    }
    
    .modal-title {
        font-size: 18px;
        margin-bottom: 10px;
        padding-right: 0;
    }
    
    .modal-authors {
        font-size: 13px;
        margin-bottom: 16px;
    }
    
    .modal-significance {
        font-size: 14px;
        padding: 14px;
        margin-bottom: 16px;
    }
    
    .modal-tags {
        gap: 6px;
        margin-bottom: 20px;
    }
    
    .modal-tags .tag {
        font-size: 11px;
        padding: 5px 12px;
    }
    
    .modal-notes {
        padding: 16px;
        margin-bottom: 20px;
    }
    
    .modal-notes h3 {
        font-size: 15px;
        margin-bottom: 12px;
    }
    
    .notes-content {
        font-size: 13px;
    }
    
    .modal-actions {
        margin: 0 -20px -20px;
        padding: 14px 20px;
    }
    
    .btn {
        padding: 14px 20px;
        font-size: 14px;
    }
    
    .footer {
        padding: 24px 0;
        font-size: 13px;
    }
    
    .footer .source-credit {
        font-size: 11px;
        line-height: 1.5;
    }
}

@media (min-width: 1200px) {
    .bento-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (min-width: 1600px) {
    .bento-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}