:root {
    --primary-blue: #45ADFF;
    --text-dark: #1a1a1a;
    --text-gray: #55636b;
    --bg-light: #ffffff;
    --border-color: #e5e7eb;
    --bg-gray: #f8fafc;
}

body {
    font-family: 'Lexend', 'Instrument Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.7;
    color: var(--text-dark);
    margin: 0;
    padding: 0;
    background: var(--bg-light);
}

a { color: var(--primary-blue); }

.nav-link.active { color: var(--primary-blue); font-weight: 700; }

/* ---------- Blog index ---------- */
.blog-hero {
    text-align: center;
    padding: 70px 20px 10px;
}

.blog-hero h1 {
    font-size: 2.8rem;
    letter-spacing: -1px;
    margin: 0 0 14px;
    line-height: 1.15;
}

.blog-hero .blog-tagline {
    color: var(--text-gray);
    font-size: 1.15rem;
    max-width: 640px;
    margin: 0 auto;
}

.blog-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 40px 20px 70px;
}

.post-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.post-card {
    padding: 0;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: #fff;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.post-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
}

.card-image {
    width: 100%;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    display: block;
    border-bottom: 1px solid var(--border-color);
}

.card-body {
    padding: 20px 22px;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.card-date {
    font-size: 0.8rem;
    color: var(--text-gray);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin: 0 0 8px;
}

.card-title {
    font-size: 1.15rem;
    line-height: 1.4;
    font-weight: 700;
    margin: 0 0 10px;
}

.card-title a { color: inherit; text-decoration: none; }
.card-title a:hover { color: var(--primary-blue); }

.card-excerpt {
    color: var(--text-gray);
    font-size: 0.95rem;
    margin: 0 0 14px;
}

.card-link {
    margin-top: auto;
    font-weight: 600;
    text-decoration: none;
}

/* ---------- Article page ---------- */
.breadcrumb {
    max-width: 780px;
    margin: 0 auto;
    padding: 26px 20px 0;
    font-size: 0.85rem;
    color: var(--text-gray);
}

.breadcrumb a { color: var(--text-gray); text-decoration: none; }
.breadcrumb a:hover { color: var(--primary-blue); }

.article-wrap {
    max-width: 780px;
    margin: 0 auto;
    padding: 24px 20px 70px;
}

.post-header {
    margin-bottom: 26px;
}

.post-header h1 {
    font-size: 2.2rem;
    line-height: 1.25;
    letter-spacing: -0.5px;
    margin: 0 0 14px;
}

.post-meta {
    color: var(--text-gray);
    font-size: 0.9rem;
}

.post-cover {
    width: 100%;
    border-radius: 12px;
    margin-bottom: 30px;
}

.blog-post { color: var(--text-dark); }

.blog-post > *:first-child { margin-top: 0; }

.blog-post h2 {
    font-size: 1.55rem;
    line-height: 1.35;
    margin: 40px 0 16px;
}

.blog-post h3 {
    font-size: 1.25rem;
    line-height: 1.4;
    margin: 32px 0 12px;
}

.blog-post h4 {
    font-size: 1.05rem;
    margin: 26px 0 10px;
}

.blog-post p {
    font-size: 1.05rem;
    line-height: 1.8;
    margin: 0 0 20px;
    color: #2b3440;
}

.blog-post ul, .blog-post ol {
    margin: 0 0 20px;
    padding-left: 24px;
}

.blog-post li { margin-bottom: 8px; line-height: 1.8; }

.blog-post strong { font-weight: 700; }

.blog-post blockquote {
    border-left: 4px solid var(--primary-blue);
    margin: 26px 0;
    padding: 4px 20px;
    background: var(--bg-gray);
    border-radius: 0 8px 8px 0;
    color: var(--text-gray);
}

.blog-post blockquote p { margin: 8px 0; }

.blog-post code {
    background: #f1f5f9;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    padding: 2px 6px;
    font-size: 0.92em;
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.blog-post pre {
    background: #0f172a;
    color: #e2e8f0;
    padding: 20px;
    border-radius: 10px;
    overflow-x: auto;
    margin: 24px 0;
    font-size: 0.92em;
}

.blog-post pre code {
    background: none;
    border: 0;
    padding: 0;
    color: inherit;
}

.blog-post img {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    margin: 24px 0;
}

.blog-post table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    font-size: 0.95rem;
}

.blog-post th, .blog-post td {
    border: 1px solid var(--border-color);
    padding: 10px 12px;
    text-align: left;
}

.blog-post th { background: var(--bg-gray); font-weight: 700; }

.blog-post hr {
    border: 0;
    border-top: 1px solid var(--border-color);
    margin: 34px 0;
}

/* ---------- Prev / next ---------- */
.post-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 44px;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
}

.post-nav a {
    text-decoration: none;
    color: var(--text-dark);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 16px 18px;
    font-size: 0.95rem;
    transition: border-color 0.2s ease;
}

.post-nav a:hover { border-color: var(--primary-blue); color: var(--primary-blue); }

.post-nav .dir { display: block; font-size: 0.8rem; color: var(--text-gray); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 4px; }

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

/* ---------- Responsive ---------- */
@media (max-width: 700px) {
    .blog-hero h1 { font-size: 2rem; }
    .post-header h1 { font-size: 1.7rem; }
    .post-nav { grid-template-columns: 1fr; }
    .post-nav .next { text-align: left; }
}