/* chiengpt.com — page « Pourquoi ? ». Lisible, calme, une colonne. */

:root {
    --on-accent: #ffffff;
    --bg: #0e0e0e;
    --bg-2: #161616;
    --fg: #f2f2f2;
    --dim: #9a9a9a;
    --border: #2a2a2a;
    --accent: #ff7a1a;
    --line: var(--border);
    --font-sans: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --font-serif: "Playfair Display", Georgia, serif;
    --max: 720px;
}

body.light-theme {
    --bg: #fbfaf7;
    --bg-2: #ffffff;
    --fg: #1a1a1a;
    --dim: #666666;
    --border: #e4e1da;
    --accent: #e8650f;
}

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

html { scroll-behavior: smooth; }

body {
    background: var(--bg);
    color: var(--fg);
    font-family: var(--font-sans);
    font-size: 1.05rem;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    transition: background-color .15s ease, color .15s ease;
}

a { color: inherit; }

/* Navigation */
.nav {
    position: sticky;
    top: 0;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: .8rem 1.25rem;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
}

.nav-cta {
    display: inline-block;
    padding: .5rem 1.1rem;
    border-radius: 999px;
    background: var(--accent);
    color: var(--on-accent);
    font-weight: 600;
    text-decoration: none;
}
.nav-cta:hover { filter: brightness(1.08); }

/* Contenu */
main {
    max-width: var(--max);
    margin: 0 auto;
    padding: 3rem 1.25rem 4rem;
}

.hero { padding: 1.5rem 0 2.5rem; }

.kicker {
    color: var(--accent);
    font-weight: 600;
    font-size: .9rem;
    margin-bottom: .6rem;
}

h1 {
    font-size: clamp(2rem, 5.5vw, 3rem);
    line-height: 1.15;
    letter-spacing: -0.02em;
    font-weight: 700;
    margin-bottom: 1.25rem;
}
h1 em {
    font-family: var(--font-serif);
    font-style: italic;
    font-weight: 500;
    color: var(--dim);
}

h2 {
    font-size: clamp(1.4rem, 3.2vw, 1.8rem);
    line-height: 1.25;
    letter-spacing: -0.01em;
    font-weight: 700;
    margin-bottom: 1rem;
}

.lead { font-size: 1.15rem; color: var(--dim); }

.block {
    padding: 2.25rem 0;
    border-top: 1px solid var(--border);
}
.block p { margin-bottom: 1rem; }
.block p:last-child { margin-bottom: 0; }

.note {
    background: var(--bg-2);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent);
    border-radius: 10px;
    padding: .9rem 1.1rem;
    font-size: .95rem;
    color: var(--dim);
    margin-top: 1.25rem;
}

.steps, .plain {
    margin: .5rem 0 1rem 1.4rem;
}
.steps li, .plain li { margin-bottom: .6rem; }

.inline-link {
    color: var(--accent);
    font-weight: 600;
    text-decoration: none;
    border-bottom: 1px solid currentColor;
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: .75rem;
    margin-top: 1.5rem;
}

.btn {
    display: inline-block;
    padding: .8rem 1.4rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    background: var(--bg-2);
    color: var(--fg);
    font-weight: 600;
    text-decoration: none;
    transition: transform .1s ease, filter .15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--on-accent);
}

/* Pied de page */
.foot {
    max-width: var(--max);
    margin: 0 auto;
    padding: 2rem 1.25rem 3rem;
    border-top: 1px solid var(--border);
    color: var(--dim);
    font-size: .95rem;
}
.foot-links { margin-top: .5rem; }
.foot-links a { text-decoration: none; border-bottom: 1px solid var(--border); }

@media (max-width: 600px) {
    body { font-size: 1rem; }
    main { padding-top: 2rem; }
    .nav { padding: .7rem 1rem; }
}