:root {
    /* Monotone Palette */
    --bg-primary: #0a0a0a;
    --bg-secondary: #111111;
    --bg-tertiary: #1a1a1a;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-hover: rgba(255, 255, 255, 0.06);

    --text-primary: #f0f0f0;
    --text-secondary: rgba(240, 240, 240, 0.85);
    --text-tertiary: rgba(240, 240, 240, 0.65);

    --accent: #ffffff;
    --accent-glow: rgba(255, 255, 255, 0.15);
    --accent-subtle: rgba(255, 255, 255, 0.08);

    --border: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.2);

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'Space Mono', monospace;

    /* Spacing */
    --section-pad: clamp(4rem, 10vw, 8rem);
    --container-max: 1200px;

    /* Transitions */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-in-out: cubic-bezier(0.76, 0, 0.24, 1);
}

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

html {
    scroll-behavior: smooth;
    background: var(--bg-primary);
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* ---- Particle Canvas ---- */
#particle-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
    animation: canvasFadeIn 1.2s ease-out forwards;
}

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

/* ---- Scan Line Overlay ---- */
.scan-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    pointer-events: none;
    background: repeating-linear-gradient(0deg,
            transparent,
            transparent 2px,
            rgba(0, 0, 0, 0.03) 2px,
            rgba(0, 0, 0, 0.03) 4px);
}

/* ============================================
   Navigation
   ============================================ */
.top-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem clamp(1.5rem, 4vw, 3rem);
    background: rgba(10, 10, 10, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: background 0.4s var(--ease-out);
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
}

.nav-sz {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    font-weight: 700;
    width: 1.8rem;
    height: 1.8rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-hover);
    letter-spacing: -0.02em;
}

.nav-brand {
    font-family: var(--font-sans);
    font-weight: 300;
    font-size: 0.75rem;
    letter-spacing: 0.3em;
    text-transform: uppercase;
}

.nav-link {
    font-family: var(--font-mono);
    font-size: 0.65rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    transition: color 0.3s var(--ease-out);
}

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

/* ============================================
   Section Common Styles
   ============================================ */
.section-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 clamp(1.5rem, 4vw, 3rem);
    width: 100%;
}

.section-label {
    font-family: var(--font-mono);
    font-size: 0.65rem;
    letter-spacing: 0.4em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    margin-bottom: 1rem;
}

.section-title {
    font-family: var(--font-sans);
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 200;
    letter-spacing: 0.02em;
    margin-bottom: 2rem;
    line-height: 1.1;
}

.section-desc {
    font-size: 0.95rem;
    font-weight: 300;
    color: var(--text-secondary);
    max-width: 600px;
    margin-bottom: 3rem;
    line-height: 1.8;
}

/* ============================================
   Blog Page
   ============================================ */
.blog-page {
    min-height: 100vh;
    position: relative;
    z-index: 2;
    padding-top: 3.5rem;
}

.blog-header {
    padding: var(--section-pad) 0 2rem;
}

.blog-grid {
    display: flex;
    flex-direction: column;
}

.blog-card {
    display: flex;
    align-items: center;
    gap: 2rem;
    padding: 1.2rem 0;
    border-bottom: 1px solid var(--border);
    text-decoration: none;
    color: inherit;
    cursor: pointer;
    position: relative;
    transition: all 0.3s var(--ease-out);
}

.blog-card:first-child {
    border-top: 1px solid var(--border);
}

.blog-card:hover {
    padding-left: 1rem;
    background: linear-gradient(90deg, var(--bg-card-hover), transparent);
}

.blog-card-thumb {
    width: 80px;
    min-width: 80px;
    height: 80px;
    overflow: hidden;
    border: 1px solid var(--border);
    flex-shrink: 0;
}

.blog-card-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.4s var(--ease-out);
}

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

.blog-card-content {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    min-width: 0;
    flex: 1;
}

.blog-card-date {
    font-family: var(--font-mono);
    font-size: 0.55rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-tertiary);
}

.blog-card-title {
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 300;
    letter-spacing: 0.01em;
    line-height: 1.5;
    color: var(--text-primary);
}

.blog-card-excerpt {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    font-weight: 400;
    color: var(--text-tertiary);
    letter-spacing: 0.1em;
    line-height: 1.8;
}

.blog-card-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-top: 0.2rem;
}

.blog-card-tag {
    font-family: var(--font-mono);
    font-size: 0.55rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    padding: 0.2rem 0.5rem;
    border: 1px solid var(--border);
    display: inline-block;
    width: fit-content;
}

/* Blog Empty State */
.blog-empty {
    padding: 4rem 0;
    text-align: center;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.blog-empty p {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
}

/* ============================================
   Summary Button & Panel
   ============================================ */
.summary-section {
    margin-bottom: 2.5rem;
}

.summary-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.7rem 1.4rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all 0.4s var(--ease-out);
    color: var(--text-secondary);
}

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

.summary-btn.active {
    border-color: var(--border-hover);
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.summary-btn-icon {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 700;
    width: 1.6rem;
    height: 1.6rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-hover);
    letter-spacing: -0.02em;
    flex-shrink: 0;
}

.summary-btn-text {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.summary-panel {
    display: grid;
    grid-template-rows: 0fr;
    opacity: 0;
    transition: grid-template-rows 0.5s var(--ease-out),
                opacity 0.4s var(--ease-out),
                margin-top 0.5s var(--ease-out);
    margin-top: 0;
}

.summary-panel.open {
    grid-template-rows: 1fr;
    opacity: 1;
    margin-top: 1.5rem;
}

.summary-panel-inner {
    overflow: hidden;
    min-height: 0;
}

.summary-panel-label {
    font-family: var(--font-mono);
    font-size: 0.55rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
}

.summary-list {
    list-style: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0;
}

.summary-list li {
    font-size: 0.85rem;
    font-weight: 300;
    color: var(--text-secondary);
    line-height: 1.8;
    padding: 0.8rem 0 0.8rem 1.2rem;
    border-bottom: 1px solid var(--border);
    position: relative;
}

.summary-list li:last-child {
    border-bottom: none;
}

.summary-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 1.15rem;
    width: 4px;
    height: 4px;
    background: var(--text-tertiary);
}

/* ============================================
   Blog Article Page
   ============================================ */
.article-page {
    min-height: 100vh;
    position: relative;
    z-index: 2;
    padding-top: 3.5rem;
}

.article-header {
    padding: var(--section-pad) 0 2rem;
    border-bottom: 1px solid var(--border);
    margin-bottom: 3rem;
}

.article-meta {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.article-date {
    font-family: var(--font-mono);
    font-size: 0.65rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-tertiary);
}

.article-category {
    font-family: var(--font-mono);
    font-size: 0.55rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    padding: 0.2rem 0.5rem;
    border: 1px solid var(--border);
}

.article-title {
    font-family: var(--font-sans);
    font-size: clamp(1.8rem, 4vw, 3rem);
    font-weight: 200;
    letter-spacing: 0.02em;
    line-height: 1.3;
    margin-bottom: 1rem;
}

.article-subtitle {
    font-size: 1rem;
    font-weight: 300;
    color: var(--text-secondary);
    line-height: 1.7;
    max-width: 700px;
}

.article-hero-image {
    width: 100%;
    margin-bottom: 2rem;
    border: 1px solid var(--border);
    overflow: hidden;
}

.article-hero-image img {
    width: 100%;
    height: auto;
    display: block;
}

.article-body {
    width: 100%;
    padding-bottom: var(--section-pad);
}

.article-body h2 {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    font-weight: 400;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    margin-top: 3rem;
    margin-bottom: 1rem;
}

.article-body h3 {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-secondary);
    margin-top: 2rem;
    margin-bottom: 0.75rem;
}

.article-body p {
    font-size: 1.05rem;
    font-weight: 300;
    color: var(--text-secondary);
    line-height: 2;
    margin-bottom: 1.5rem;
}

.article-body ul,
.article-body ol {
    font-size: 1.05rem;
    font-weight: 300;
    color: var(--text-secondary);
    line-height: 2;
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
}

.article-body li {
    margin-bottom: 0.5rem;
}

.article-body a {
    color: var(--text-primary);
    border-bottom: 1px solid var(--border);
    transition: border-color 0.3s var(--ease-out);
}

.article-body a:hover {
    border-bottom-color: var(--border-hover);
}

.article-body strong {
    font-weight: 500;
    color: var(--text-primary);
}

.article-body hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 3rem 0;
}

.article-body blockquote {
    border-left: 2px solid var(--border-hover);
    padding-left: 1.5rem;
    margin: 2rem 0;
    font-style: italic;
    color: var(--text-secondary);
}

.article-body code {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 0.15rem 0.4rem;
}

.article-body pre {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    padding: 1.5rem;
    overflow-x: auto;
    margin-bottom: 1.5rem;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

.article-body pre code {
    background: none;
    border: none;
    padding: 0;
}

.article-back {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    transition: color 0.3s var(--ease-out);
    margin-bottom: 2rem;
}

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

.article-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1px;
    background: var(--border);
    border: 1px solid var(--border);
    margin-top: 3rem;
}

.article-nav-link {
    padding: 2rem;
    background: var(--bg-primary);
    transition: all 0.4s var(--ease-out);
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.article-nav-link:hover {
    background: var(--bg-tertiary);
}

.article-nav-link.next {
    text-align: right;
    align-items: flex-end;
}

.article-nav-label {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-tertiary);
}

.article-nav-title {
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 300;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    position: relative;
    z-index: 2;
    border-top: 1px solid var(--border);
    padding: 2rem clamp(1.5rem, 4vw, 3rem);
}

.footer-inner {
    max-width: var(--container-max);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-family: var(--font-sans);
    font-weight: 300;
    font-size: 0.8rem;
    letter-spacing: 0.2em;
    color: var(--text-tertiary);
}

.footer-sz {
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 0.7rem;
    width: 1.6rem;
    height: 1.6rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
}

.footer-links {
    display: flex;
    gap: 1rem;
}

.footer-policy-link {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-tertiary);
    transition: color 0.3s var(--ease-out);
}

.footer-policy-link:hover {
    color: var(--text-primary);
}

.footer-copy {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    color: var(--text-tertiary);
    letter-spacing: 0.05em;
}

/* ============================================
   Scroll Animations
   ============================================ */
[data-animate] {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}

[data-animate].visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============================================
   Error Page (404)
   ============================================ */
.error-page {
    min-height: 100vh;
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding-top: 3.5rem;
}

.error-content {
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    max-width: var(--container-max);
    padding: 0 clamp(1.5rem, 4vw, 3rem);
}

.error-code {
    font-family: var(--font-mono);
    font-size: clamp(6rem, 15vw, 12rem);
    font-weight: 700;
    line-height: 1;
    color: var(--text-primary);
    opacity: 0.08;
    letter-spacing: -0.02em;
}

.error-symbol {
    font-family: var(--font-mono);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    width: 5rem;
    height: 5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    margin-top: -2rem;
}

.error-title {
    font-family: var(--font-sans);
    font-size: 1.2rem;
    font-weight: 300;
    letter-spacing: 0.08em;
    color: var(--text-primary);
    margin-top: 1rem;
}

.error-desc {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
    max-width: 320px;
}

.error-link {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 0.8rem 2rem;
    border: 1px solid var(--border);
    margin-top: 1.5rem;
    transition: all 0.3s var(--ease-out);
}

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

/* ============================================
   Responsive — Mobile
   ============================================ */
@media (max-width: 768px) {
    .blog-card {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .blog-card-thumb {
        width: 100%;
        height: 160px;
    }

    .article-nav {
        grid-template-columns: 1fr;
    }

    .article-nav-link.next {
        text-align: left;
        align-items: flex-start;
    }

    .footer-inner {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}