:root {
    /* Colors */
    --color-bg: #FFFFFF;
    --color-bg-alt: #F8FAFC;
    --color-text-primary: #1E293B;
    /* --color-text-secondary: #64748B; */
    --color-text-secondary: #4B5563;
    --color-primary: #2563EB;
    /* Royal Blue */
    --color-primary-hover: #1D4ED8;
    --color-accent: #FF6B6B;
    /* Coral */
    --color-accent-hover: #E65555;
    --color-border: #E2E8F0;
    --color-card-shadow: rgba(0, 0, 0, 0.04);
    --color-card-hover-shadow: rgba(0, 0, 0, 0.1);

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

img {
    max-width: 100%;
    display: block;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* Typography Utilities */
.h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    line-height: 1.2;
}

.h2 {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    line-height: 1.25;
}

.h3 {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.025em;
    line-height: 1.3;
}

.text-lg {
    font-size: 1.125rem;
}

.text-sm {
    font-size: 0.875rem;
}

.text-xs {
    font-size: 0.75rem;
}

.font-bold {
    font-weight: 700;
}

.font-medium {
    font-weight: 500;
}

.text-secondary {
    color: var(--color-text-secondary);
}

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

/* Layout Utilities */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-between {
    justify-content: space-between;
}

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

.justify-end {
    justify-content: flex-end;
}

.gap-sm {
    gap: var(--spacing-sm);
}

.gap-md {
    gap: var(--spacing-md);
}

.gap-lg {
    gap: var(--spacing-lg);
}

/* Padding Utilities */
.p-sm {
    padding: var(--spacing-sm);
}

.p-md {
    padding: var(--spacing-md);
}

.p-lg {
    padding: var(--spacing-lg);
}

.p-xl {
    padding: var(--spacing-xl);
}

/* Margin Utilities */
.mb-2 {
    margin-bottom: var(--spacing-sm);
}

.mb-4 {
    margin-bottom: var(--spacing-md);
}

.mb-8 {
    margin-bottom: var(--spacing-xl);
}

.mt-2 {
    margin-top: var(--spacing-sm);
}

.mt-4 {
    margin-top: var(--spacing-md);
}

.mt-8 {
    margin-top: var(--spacing-xl);
}

.w-full {
    width: 100%;
}

.text-center {
    text-align: center;
}

.inline-block {
    display: inline-block;
}

.grid {
    display: grid;
}

.grid-cols-1 {
    grid-template-columns: repeat(1, 1fr);
}

.grid-cols-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
    grid-template-columns: repeat(3, 1fr);
}

/* Components */

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(37, 99, 235, 0.2);
}

.btn-donate {
    background-color: var(--color-accent);
    color: white;
    border-radius: var(--radius-full);
}

.btn-donate:hover {
    background-color: var(--color-accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(255, 107, 107, 0.3);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--color-border);
    color: var(--color-text-secondary);
}

.btn-outline:hover {
    border-color: var(--color-text-primary);
    color: var(--color-text-primary);
}

.btn-ghost {
    background: transparent;
    color: var(--color-text-secondary);
    padding: 0.5rem 1rem;
}

.btn-ghost:hover {
    background-color: var(--color-bg-alt);
    color: var(--color-text-primary);
}

/* Header */
.header {
    height: 80px;
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(8px);
    z-index: 50;
    display: flex;
    align-items: center;
}

.nav-link {
    font-weight: 500;
    color: var(--color-text-secondary);
    padding: 0.5rem 0;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-text-primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -28px;
    /* header height/2 roughly minus padding */
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--color-primary);
    border-radius: 3px 3px 0 0;
}

/* Cards */
.card {
    background: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 15px -3px var(--color-card-hover-shadow), 0 4px 6px -2px var(--color-card-hover-shadow);
    border-color: transparent;
}

.card-img-wrapper {
    width: 100%;
    aspect-ratio: 16/9;
    overflow: hidden;
    background-color: var(--color-bg-alt);
    display: flex;
    align-items: center;
    justify-content: center;
}

.card-img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: var(--spacing-xs);
    transition: transform var(--transition-normal);
}

.card:hover .card-img {
    transform: scale(1.05);
}

.card-content {
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.card-title {
    font-weight: 700;
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xs);
    line-height: 1.4;
}

.card-meta {
    margin-top: auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.tag {
    background-color: var(--color-bg-alt);
    padding: 0.25rem 0.625rem;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Post Detail */
.post-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-2xl) auto;
}

.post-image-container {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 4px 6px -1px var(--color-card-shadow);
    border: 1px solid var(--color-border);
    margin-bottom: var(--spacing-xl);
}

.markdown-body {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.125rem;
    color: var(--color-text-primary);
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3 {
    margin-top: 1.5em;
    margin-bottom: 0.5em;
    color: var(--color-text-primary);
}

.markdown-body p {
    margin-bottom: 1.25em;
}

.markdown-body ul,
.markdown-body ol {
    margin-bottom: 1.25em;
    padding-left: 1.5em;
}

.markdown-body li {
    margin-bottom: 0.5em;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.4s ease-out forwards;
}

/* Responsive Utilities */
.mobile-only {
    display: none;
}

@media (max-width: 1024px) {
    .desktop-only {
        display: none !important;
    }

    .mobile-only {
        display: block;
    }

    /* Bottom nav needs flex display */
    .mobile-only.bottom-nav {
        display: flex;
    }
}

/* ═══════════════════════════════════════════════════════════════════════════
   MOBILE/TABLET NATIVE UI - iOS/Android App Experience
   Target: iPhone 12+, iPad, Samsung Galaxy S24/M30, OnePlus 10, Tablets
   ═══════════════════════════════════════════════════════════════════════════ */

@media (max-width: 1024px) {

    /* Mobile Design Tokens */
    :root {
        --mobile-spacing-xs: 4px;
        --mobile-spacing-sm: 8px;
        --mobile-spacing-md: 16px;
        --mobile-spacing-lg: 20px;
        --mobile-spacing-xl: 24px;
        --mobile-radius: 16px;
        --mobile-touch-target: 44px;
        --bottom-nav-height: 80px;
    }

    /* Safe Area Support for Notch Devices */
    body {
        padding-bottom: calc(var(--bottom-nav-height) + env(safe-area-inset-bottom, 0px));
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Typography - iOS Large Title Style
       ───────────────────────────────────────────────────────────────────────── */
    .h1 {
        font-size: 1.75rem;
        line-height: 1.2;
        letter-spacing: -0.02em;
    }

    .h2 {
        font-size: 1.5rem;
        line-height: 1.25;
    }

    .h3 {
        font-size: 1.25rem;
    }

    .text-lg {
        font-size: 1rem;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Layout & Containers
       ───────────────────────────────────────────────────────────────────────── */
    .container {
        padding: 0 var(--mobile-spacing-md);
    }

    .grid-cols-3,
    .grid-cols-2 {
        grid-template-columns: 1fr;
        gap: var(--mobile-spacing-md);
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Mobile Header - Simplified
       ───────────────────────────────────────────────────────────────────────── */
    .header {
        height: 56px;
        padding: 0 var(--mobile-spacing-md);
    }

    .header .container {
        padding: 0;
    }

    .header .logo span {
        font-size: 1rem;
    }

    .header .logo svg {
        width: 28px;
        height: 28px;
    }

    .nav-links {
        display: none !important;
    }

    .btn-donate {
        padding: 8px 16px;
        font-size: 0.75rem;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Bottom Tab Bar - iOS Style Navigation
       ───────────────────────────────────────────────────────────────────────── */
    .bottom-nav {
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        height: var(--bottom-nav-height);
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-top: 1px solid var(--color-border);
        display: flex;
        justify-content: space-around;
        align-items: center;
        padding-bottom: env(safe-area-inset-bottom, 0px);
        z-index: 1000;
    }

    .bottom-nav-item {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        flex: 1;
        height: 100%;
        padding: 8px 0;
        color: var(--color-text-secondary);
        font-size: 10px;
        font-weight: 500;
        text-decoration: none;
        transition: color 0.2s ease;
        -webkit-tap-highlight-color: transparent;
    }

    .bottom-nav-item svg {
        width: 24px;
        height: 24px;
        margin-bottom: 4px;
        stroke-width: 1.5;
    }

    .bottom-nav-item.active {
        color: var(--color-primary);
    }

    .bottom-nav-item.active svg {
        stroke-width: 2;
    }

    .bottom-nav-item.donate-tab {
        color: var(--color-accent);
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Buttons - Touch Optimized
       ───────────────────────────────────────────────────────────────────────── */
    .btn {
        min-height: var(--mobile-touch-target);
        padding: 12px 20px;
        font-size: 0.9375rem;
        border-radius: 12px;
    }

    .btn-primary {
        width: 100%;
    }

    .btn-outline {
        width: 100%;
    }

    .btn-ghost {
        min-height: var(--mobile-touch-target);
        padding: 10px 16px;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Cards - Full Width Mobile Style
       ───────────────────────────────────────────────────────────────────────── */
    .card {
        border-radius: var(--mobile-radius);
        margin-bottom: var(--mobile-spacing-md);
    }

    .card:hover {
        transform: none;
        /* Disable hover lift on mobile */
    }

    .card-img-wrapper {
        aspect-ratio: 16/10;
    }

    .card-content {
        padding: var(--mobile-spacing-md);
    }

    .card-title {
        font-size: 1rem;
        line-height: 1.3;
    }

    .card-meta {
        font-size: 0.8125rem;
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .card-meta .flex {
        justify-content: flex-start;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Mobile Carousel - Swipeable with Peek
       ───────────────────────────────────────────────────────────────────────── */
    .mobile-carousel {
        display: flex;
        overflow-x: auto;
        scroll-snap-type: x mandatory;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        -ms-overflow-style: none;
        padding: 0 var(--mobile-spacing-md);
        gap: var(--mobile-spacing-md);
    }

    .mobile-carousel::-webkit-scrollbar {
        display: none;
    }

    .mobile-carousel-item {
        flex: 0 0 85%;
        scroll-snap-align: center;
    }

    .mobile-carousel-item .card {
        margin-bottom: 0;
    }

    .carousel-dots {
        display: flex;
        justify-content: center;
        gap: 8px;
        padding: var(--mobile-spacing-md) 0;
    }

    .carousel-dot {
        width: 8px;
        height: 8px;
        border-radius: 50%;
        background: var(--color-border);
        transition: all 0.3s ease;
    }

    .carousel-dot.active {
        background: var(--color-primary);
        width: 24px;
        border-radius: 4px;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Hero Section - Mobile Optimized
       ───────────────────────────────────────────────────────────────────────── */
    .mobile-hero {
        padding: var(--mobile-spacing-xl) var(--mobile-spacing-md);
        text-align: center;
    }

    .mobile-hero h1 {
        font-size: 1.75rem;
        margin-bottom: var(--mobile-spacing-md);
    }

    .mobile-hero p {
        font-size: 1rem;
        margin-bottom: var(--mobile-spacing-lg);
        color: var(--color-text-secondary);
    }

    .mobile-hero .btn {
        width: 100%;
        max-width: 280px;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Quick Links - Compact Icon Strip
       ───────────────────────────────────────────────────────────────────────── */
    .mobile-quick-links {
        display: flex;
        justify-content: space-around;
        padding: var(--mobile-spacing-lg) var(--mobile-spacing-md);
        background: var(--color-bg-alt);
        border-radius: var(--mobile-radius);
        margin: var(--mobile-spacing-md);
    }

    .mobile-quick-link {
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 8px;
        color: var(--color-text-secondary);
        font-size: 0.75rem;
        font-weight: 500;
    }

    .mobile-quick-link-icon {
        width: 48px;
        height: 48px;
        background: white;
        border-radius: 12px;
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 24px;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Post Detail - Mobile Layout
       ───────────────────────────────────────────────────────────────────────── */
    .post-header {
        text-align: left;
        padding: var(--mobile-spacing-md);
        margin-bottom: var(--mobile-spacing-md);
    }

    .post-header h1 {
        font-size: 1.5rem;
    }

    .post-image-container {
        border-radius: 0;
        margin: 0 calc(-1 * var(--mobile-spacing-md));
        margin-bottom: var(--mobile-spacing-md);
        border-left: none;
        border-right: none;
    }

    .markdown-body {
        font-size: 1rem;
        padding: 0 var(--mobile-spacing-md);
    }

    /* Mobile Action Bar - Sticky Bottom */
    .mobile-action-bar {
        position: fixed;
        bottom: var(--bottom-nav-height);
        left: 0;
        right: 0;
        background: white;
        border-top: 1px solid var(--color-border);
        padding: var(--mobile-spacing-sm) var(--mobile-spacing-md);
        padding-bottom: calc(var(--mobile-spacing-sm) + env(safe-area-inset-bottom, 0px));
        display: flex;
        gap: var(--mobile-spacing-sm);
        z-index: 100;
    }

    .mobile-action-bar .btn {
        flex: 1;
        padding: 12px;
        font-size: 0.875rem;
    }

    /* Post Navigation - Mobile */
    .post-nav-mobile {
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: var(--mobile-spacing-lg) var(--mobile-spacing-md);
        gap: var(--mobile-spacing-md);
    }

    .post-nav-btn {
        flex: 1;
        display: flex;
        flex-direction: column;
        padding: var(--mobile-spacing-md);
        background: var(--color-bg-alt);
        border-radius: var(--mobile-radius);
        text-decoration: none;
        color: var(--color-text-primary);
    }

    .post-nav-btn.prev {
        text-align: left;
    }

    .post-nav-btn.next {
        text-align: right;
    }

    .post-nav-label {
        font-size: 0.75rem;
        color: var(--color-text-secondary);
        margin-bottom: 4px;
    }

    .post-nav-title {
        font-weight: 600;
        font-size: 0.875rem;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Contributors Section - Mobile
       ───────────────────────────────────────────────────────────────────────── */
    .contributor-card-mobile {
        flex-direction: column !important;
        text-align: center;
        padding: var(--mobile-spacing-lg) !important;
        gap: var(--mobile-spacing-md) !important;
    }

    .contributor-card-mobile img:first-child {
        width: 80px !important;
        height: 80px !important;
    }

    .contributor-card-mobile .flex-col {
        text-align: center;
        align-items: center;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Tags - Mobile Sizing
       ───────────────────────────────────────────────────────────────────────── */
    .tag {
        font-size: 0.6875rem;
        padding: 4px 8px;
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Animations - Reduced Motion Support
       ───────────────────────────────────────────────────────────────────────── */
    @media (prefers-reduced-motion: reduce) {
        .fade-in {
            animation: none;
        }
    }

    /* ─────────────────────────────────────────────────────────────────────────
       Footer - Mobile Adjustments (Above Bottom Nav)
       ───────────────────────────────────────────────────────────────────────── */
    footer {
        margin-bottom: var(--bottom-nav-height);
    }
}