/* The site's reading pages (blog, privacy): the homepage's dark ground, type
   and nav, around a column of prose. The homepage keeps its own inline styles;
   the exercise library has css/exercises.css. Fonts come from css/fonts.css. */

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

:root {
    --bg: #06070D;
    --bg-raise: #0B0D17;
    --surface: #10121D;
    --line: rgba(255, 255, 255, 0.08);
    --line-strong: rgba(255, 255, 255, 0.14);
    --text: #F4F1EA;
    --muted: rgba(236, 237, 242, 0.68);
    --dim: rgba(236, 237, 242, 0.44);
    --ember: #FF7A4D;
    --ember-grad: linear-gradient(95deg, #FFB27A 0%, #FF7A4D 55%, #F25F5C 100%);
    --indigo: #7D8BCF;
    --label: #A9B1E6;
    --display: 'Inter Tight', -apple-system, BlinkMacSystemFont, 'SF Pro Display', system-ui, sans-serif;
    --body: -apple-system, BlinkMacSystemFont, 'SF Pro Text', system-ui, 'Segoe UI', Roboto, sans-serif;
    --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
    --gutter: clamp(20px, 5vw, 72px);
}

html {
    background: var(--bg);
}

body {
    font-family: var(--body);
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a {
    color: inherit;
}

img {
    max-width: 100%;
}

/* ── Nav ── */

.nav {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(6, 7, 13, 0.78);
    -webkit-backdrop-filter: blur(18px) saturate(1.4);
    backdrop-filter: blur(18px) saturate(1.4);
    border-bottom: 1px solid var(--line);
}

.nav-inner {
    height: 68px;
    display: flex;
    align-items: center;
    gap: 24px;
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 var(--gutter);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: var(--display);
    font-weight: 800;
    font-size: 19px;
    letter-spacing: -0.02em;
    text-decoration: none;
}

.logo img {
    width: 30px;
    height: 30px;
    border-radius: 8px;
}

.back-link {
    margin-left: auto;
    font-size: 14px;
    color: var(--muted);
    text-decoration: none;
}

.back-link::before {
    content: "← ";
}

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

.lang-toggle {
    display: flex;
    gap: 2px;
    padding: 3px;
    border-radius: 100px;
    border: 1px solid var(--line-strong);
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.08em;
}

.lang-toggle a {
    padding: 4px 9px;
    border-radius: 100px;
    color: var(--dim);
    text-decoration: none;
}

.lang-toggle a[aria-current="page"] {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text);
}

.nav-cta {
    font-size: 14px;
    font-weight: 600;
    padding: 8px 16px;
    border-radius: 100px;
    background: var(--text);
    color: var(--bg);
    text-decoration: none;
    white-space: nowrap;
}

/* ── The column ── */

.page {
    max-width: 760px;
    margin: 0 auto;
    padding: clamp(56px, 9vw, 110px) var(--gutter) clamp(64px, 10vw, 120px);
}

.page.wide {
    max-width: 1100px;
}

.eyebrow,
.article-meta,
.last-updated {
    font-family: var(--mono);
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--label);
}

.article-meta time,
.article-meta span {
    color: inherit;
}

h1 {
    font-family: var(--display);
    font-weight: 800;
    font-size: clamp(40px, 5.4vw, 72px);
    line-height: 1;
    letter-spacing: -0.04em;
    margin: 18px 0 22px;
}

/* A post's title is a sentence, not a word: smaller than a page's. */
article.page h1 {
    font-size: clamp(34px, 4.4vw, 56px);
    line-height: 1.04;
}

.subtitle,
.page-subtitle {
    font-size: clamp(18px, 1.6vw, 21px);
    line-height: 1.6;
    color: var(--muted);
    margin-bottom: clamp(36px, 5vw, 56px);
}

/* Prose */

.page h2 {
    font-family: var(--display);
    font-weight: 800;
    font-size: clamp(26px, 2.6vw, 34px);
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin: clamp(40px, 5vw, 56px) 0 16px;
}

.page h3 {
    font-family: var(--display);
    font-weight: 800;
    letter-spacing: -0.02em;
}

.page p,
.page li {
    font-size: 17px;
    color: rgba(236, 237, 242, 0.8);
}

.page p {
    margin-bottom: 18px;
}

.page ul,
.page ol {
    margin: 0 0 22px;
    padding-left: 22px;
}

.page li {
    margin-bottom: 10px;
}

.page li::marker {
    color: var(--ember);
}

.page strong {
    color: var(--text);
}

.page p a,
.page li a {
    color: var(--text);
    text-decoration: none;
    border-bottom: 1px solid rgba(255, 122, 77, 0.5);
}

.page p a:hover,
.page li a:hover {
    border-bottom-color: var(--ember);
}

blockquote {
    margin: 36px 0;
    padding: 4px 0 4px 26px;
    border-left: 2px solid var(--ember);
}

.page blockquote p {
    font-family: var(--display);
    font-weight: 700;
    font-size: clamp(22px, 2.2vw, 28px);
    line-height: 1.3;
    letter-spacing: -0.02em;
    color: var(--text);
    margin: 0;
}

.highlight-box {
    margin: 32px 0;
    padding: 26px 28px;
    border-radius: 20px;
    border: 1px solid rgba(255, 122, 77, 0.28);
    background: radial-gradient(120% 120% at 0% 0%, rgba(255, 122, 77, 0.1), transparent 60%), var(--bg-raise);
}

.page .highlight-box p:last-child {
    margin-bottom: 0;
}

.separator {
    border: 0;
    border-top: 1px solid var(--line);
    margin: 56px 0;
}

/* App screens in a drawn phone */

.blog-image {
    margin: 40px auto;
    text-align: center;
}

.blog-image img {
    display: block;
    margin: 0 auto;
    border-radius: 34px;
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.1), 0 0 0 7px #0B0C12, 0 0 0 8px rgba(255, 255, 255, 0.08),
        0 30px 70px rgba(0, 0, 0, 0.55);
}

.blog-image figcaption {
    margin-top: 22px;
    font-size: 14px;
    color: var(--dim);
}

.blog-image-row {
    display: flex;
    justify-content: center;
    gap: clamp(20px, 5vw, 48px);
    flex-wrap: wrap;
}

.blog-image-row .blog-image {
    margin: 32px 0;
    flex: 0 1 220px;
}

/* The closing call on a post */

.cta-box {
    position: relative;
    margin-top: 16px;
    padding: clamp(32px, 5vw, 52px);
    border-radius: 28px;
    text-align: center;
    border: 1px solid var(--line);
    background: radial-gradient(90% 120% at 50% 0%, rgba(255, 122, 77, 0.14), transparent 60%), var(--bg-raise);
}

.cta-box h3 {
    font-size: clamp(26px, 3vw, 36px);
    line-height: 1.1;
    margin-bottom: 14px;
}

.page .cta-box p {
    color: var(--muted);
    max-width: 520px;
    margin: 0 auto 26px;
}

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

.hero-cta img {
    height: 52px;
    display: block;
}

/* The blog's list */

.post-list {
    display: grid;
    gap: 20px;
}

.post-card {
    display: grid;
    grid-template-columns: 260px 1fr;
    border-radius: 24px;
    overflow: hidden;
    text-decoration: none;
    border: 1px solid var(--line);
    background: var(--bg-raise);
    transition: border-color 0.3s, transform 0.3s;
}

.post-card:hover {
    border-color: var(--line-strong);
    transform: translateY(-2px);
}

.post-thumbnail {
    display: block;
    width: 100%;
    height: 100%;
    min-height: 220px;
    object-fit: cover;
}

.post-card-body {
    padding: clamp(24px, 3vw, 36px);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.page .post-card h2 {
    font-size: clamp(22px, 2.2vw, 28px);
    margin: 0 0 12px;
}

.page .post-card p {
    font-size: 15px;
    color: var(--muted);
    margin-bottom: 18px;
}

.post-meta {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--dim);
}

/* ── Footer ── */

footer {
    border-top: 1px solid var(--line);
    padding: 36px 0 44px;
    color: var(--dim);
    font-size: 13px;
}

footer .container {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 var(--gutter);
    display: flex;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
}

footer a {
    color: var(--muted);
    text-decoration: none;
}

footer a:hover {
    color: var(--text);
}

@media (max-width: 640px) {
    .nav-inner {
        gap: 14px;
    }

    .back-link {
        font-size: 13px;
    }

    .nav-cta {
        display: none;
    }

    .post-card {
        grid-template-columns: 1fr;
    }

    .post-thumbnail {
        height: 220px;
    }
}