/* OS Page — Dark microsite */

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

:root {
    --os-bg: #111110;
    --os-fg: #c8c4bc;
    --os-fg-bright: #ede9e1;
    --os-fg-muted: #8a857c;
    --os-fg-dim: #524f48;
    --os-accent: #c9a55a;
    --os-border: #222120;
    --os-font-serif: 'Source Serif 4', Georgia, serif;
    --os-font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

html {
    font-size: 18px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--os-font-serif);
    background: var(--os-bg);
    color: var(--os-fg);
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--os-fg-muted);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--os-fg-bright);
}

/* ---- Nav ---- */

.os-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem clamp(24px, 5vw, 80px);
}

.os-nav-name {
    font-family: var(--os-font-sans);
    font-size: 1rem;
    font-weight: 600;
    color: var(--os-fg-bright);
    text-decoration: none;
}

.os-nav-name:hover {
    color: #fff;
}

.os-nav-links {
    display: flex;
    gap: 2rem;
}

.os-nav-links a {
    font-family: var(--os-font-sans);
    font-size: 0.875rem;
    color: var(--os-fg-muted);
    text-decoration: none;
}

.os-nav-links a:hover {
    color: var(--os-fg-bright);
}

.os-nav-links a[href="/addenda/"] {
    color: var(--os-fg-bright);
}

/* ---- Hero ---- */

.os-hero {
    position: relative;
    width: 100%;
    overflow: hidden;
}

.os-hero-img {
    width: 100%;
    display: block;
    object-fit: cover;
}

/* ---- Intro ---- */

.os-intro {
    max-width: 1100px;
    margin: 0 auto;
    padding: 60px clamp(24px, 5vw, 80px) 0;
}

.os-intro h1 {
    font-size: 1.1rem;
    font-family: var(--os-font-sans);
    font-weight: 600;
    letter-spacing: -0.01em;
    line-height: 1.3;
    color: var(--os-fg-bright);
    margin-bottom: 0.75rem;
}

.os-intro p {
    font-size: 0.95rem;
    line-height: 1.75;
    color: var(--os-fg-muted);
    max-width: 540px;
}

/* ---- Body ---- */

.os-body {
    max-width: 1100px;
    padding: 0 clamp(24px, 5vw, 80px);
    margin: 0 auto;
}

/* ---- Core Beliefs ---- */

.os-beliefs {
    padding: 100px 0 120px;
}

.os-beliefs-label {
    font-family: var(--os-font-sans);
    font-size: 0.65rem;
    font-weight: 400;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--os-fg-dim);
    margin-bottom: 3.5rem;
}

.os-belief {
    display: flex;
    align-items: baseline;
    gap: clamp(0.6rem, 2vw, 1.2rem);
    margin-bottom: 1rem;
}

.os-belief:last-child {
    margin-bottom: 0;
}

.os-belief-a {
    font-size: clamp(2.2rem, 5vw, 3.6rem);
    font-weight: 300;
    color: var(--os-fg-bright);
    letter-spacing: -0.03em;
    line-height: 1.15;
}

.os-belief-over {
    font-family: var(--os-font-sans);
    font-size: clamp(0.7rem, 1.2vw, 0.8rem);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--os-fg-dim);
    flex-shrink: 0;
}

.os-belief-b {
    font-size: clamp(2.2rem, 5vw, 3.6rem);
    font-weight: 200;
    color: var(--os-fg-dim);
    letter-spacing: -0.03em;
    line-height: 1.15;
}

/* ---- Entries section ---- */

.os-entries {
    padding: 100px 0 40px;
}

/* ---- Group ---- */

.os-group {
    padding: 80px 0;
    border-top: 1px solid var(--os-border);
}

.os-group:first-child {
    padding-top: 0;
    border-top: none;
}

.os-group-label {
    font-family: var(--os-font-sans);
    font-size: 0.65rem;
    font-weight: 400;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--os-accent);
    opacity: 0.6;
    margin-bottom: 3rem;
}

/* ---- Entry ---- */

.os-entry {
    margin-bottom: 3.5rem;
}

.os-entry:last-child {
    margin-bottom: 0;
}

.os-statement {
    font-size: 1.3rem;
    font-weight: 400;
    color: var(--os-fg-bright);
    line-height: 1.4;
    margin-bottom: 0.6rem;
}

.os-reflection {
    font-size: 0.9rem;
    color: var(--os-fg-muted);
    line-height: 1.75;
    max-width: 800px;
}

/* Highlighted entries — stand-out statements */

.os-entry-highlight .os-statement {
    font-size: 1.5rem;
    font-weight: 300;
    letter-spacing: -0.01em;
    color: var(--os-fg-bright);
}

/* ---- Footer ---- */

.os-footer {
    padding: 3rem 0 5rem;
    border-top: 1px solid var(--os-border);
}

.os-footer a {
    font-family: var(--os-font-sans);
    font-size: 0.8rem;
    color: var(--os-fg-dim);
}

.os-footer a:hover {
    color: var(--os-fg-bright);
}

/* ---- Mobile ---- */

@media (max-width: 600px) {
    .os-nav {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .os-nav-links {
        gap: 1.25rem;
    }

    .os-intro {
        padding-top: 40px;
    }

    .os-beliefs {
        padding: 60px 0 80px;
    }

    .os-beliefs-label {
        margin-bottom: 2.5rem;
    }

    .os-belief {
        flex-wrap: wrap;
        gap: 0.4rem;
    }

    .os-group {
        padding: 50px 0;
    }

    .os-group-label {
        margin-bottom: 2rem;
    }

    .os-entry {
        margin-bottom: 2.5rem;
    }

    .os-statement {
        font-size: 1.15rem;
    }

    .os-entry-highlight .os-statement {
        font-size: 1.3rem;
    }
}