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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'IBM Plex Sans', -apple-system, sans-serif;
    background: #fff;
    color: #1d1d1f;
    line-height: 1.8;
}

nav {
    max-width: 740px;
    margin: 0 auto;
    padding: 24px 24px 0;
}

.site-name {
    font-size: 14px;
    font-weight: 600;
    letter-spacing: -0.2px;
}

.dim {
    color: #999;
}

main {
    max-width: 740px;
    margin: 0 auto;
    padding: 0 24px;
}

article {
    padding: 48px 0 80px;
}

/* Header */

.breadcrumb {
    font-size: 13px;
    color: #888;
    margin-bottom: 16px;
}

h1 {
    font-family: 'IBM Plex Serif', Georgia, serif;
    font-size: clamp(30px, 5vw, 44px);
    font-weight: 600;
    line-height: 1.2;
    color: #1d1d1f;
    margin-bottom: 20px;
    letter-spacing: -0.5px;
}

.standfirst {
    font-size: 19px;
    color: #444;
    line-height: 1.8;
    margin-bottom: 20px;
}

.meta-bar {
    font-size: 13px;
    color: #999;
    padding-bottom: 32px;
    border-bottom: 1px solid #e5e5e5;
    margin-bottom: 36px;
}

.meta-bar .sep {
    margin: 0 8px;
    color: #ddd;
}

/* TOC */

.toc {
    background: #f8f8f8;
    border-radius: 8px;
    padding: 20px 24px;
    margin-bottom: 40px;
}

.toc strong {
    display: block;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: #888;
    margin-bottom: 10px;
}

.toc ol {
    list-style: none;
    counter-reset: toc;
}

.toc li {
    counter-increment: toc;
    padding: 4px 0;
}

.toc li::before {
    content: counter(toc) ".";
    color: #bbb;
    font-size: 13px;
    margin-right: 8px;
}

.toc a {
    font-size: 15px;
    color: #1d1d1f;
    text-decoration: none;
}

.toc a:hover {
    color: #2563eb;
}

/* Body */

section {
    margin-bottom: 48px;
}

h2 {
    font-family: 'IBM Plex Serif', Georgia, serif;
    font-size: 26px;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 18px;
    letter-spacing: -0.3px;
}

article p {
    font-size: 17px;
    color: #333;
    margin-bottom: 16px;
}

article p em {
    font-style: italic;
}

article p strong {
    font-weight: 600;
    color: #1d1d1f;
}

article a {
    color: #2563eb;
    text-decoration: none;
}

article a:hover {
    text-decoration: underline;
}

/* Callout */

.callout {
    background: #f0f4ff;
    border-left: 3px solid #2563eb;
    padding: 18px 22px;
    border-radius: 0 8px 8px 0;
    margin: 28px 0;
    font-size: 15px;
    color: #333;
    line-height: 1.7;
}

.callout strong {
    color: #1d1d1f;
}

/* Principles */

.principles {
    margin: 28px 0;
}

.principle {
    display: flex;
    gap: 20px;
    padding: 20px 0;
    border-bottom: 1px solid #eee;
}

.principle:last-child {
    border-bottom: none;
}

.principle-num {
    font-family: 'IBM Plex Serif', serif;
    font-size: 28px;
    font-weight: 600;
    color: #ddd;
    min-width: 44px;
}

.principle h3 {
    font-size: 17px;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 6px;
}

.principle p {
    font-size: 15px;
    color: #555;
    margin: 0;
}

/* App reviews */

.app-review {
    border: 1px solid #e5e5e5;
    border-radius: 10px;
    padding: 24px;
    margin-bottom: 12px;
}

.app-review.top-pick {
    border-color: #2563eb;
    background: #fafcff;
}

.app-header {
    margin-bottom: 12px;
}

.app-header .label {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: #2563eb;
    background: #e8efff;
    padding: 3px 10px;
    border-radius: 4px;
    display: inline-block;
    margin-bottom: 8px;
}

.app-review h3 {
    font-size: 19px;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 10px;
}

.app-review p {
    font-size: 15px;
    color: #555;
    margin-bottom: 10px;
}

.app-cta {
    margin-top: 16px;
}

.app-cta a {
    font-size: 15px;
    font-weight: 600;
    color: #2563eb;
}

/* Conclusion */

.conclusion {
    border-top: 1px solid #e5e5e5;
    padding-top: 40px;
}

/* Footer */

footer {
    text-align: center;
    padding: 32px 24px;
    border-top: 1px solid #eee;
}

footer p {
    font-size: 13px;
    color: #bbb;
}

@media (max-width: 600px) {
    .principle {
        flex-direction: column;
        gap: 8px;
    }

    .principle-num {
        font-size: 20px;
    }

    article {
        padding: 36px 0 60px;
    }
}