/* Birchboard site — minimal dark-first theme with a light-mode pass. */

:root {
    --bg:            #0f1310;
    --bg-panel:      #161b17;
    --bg-card:       #1a211c;
    --border:        #272d28;
    --border-soft:   #20251f;

    --text:          #e8ece7;
    --text-muted:    #a2a9a0;
    --text-subtle:   #7b827a;
    --text-tertiary: #5f6660;

    --accent:        #b4d388;   /* pale birch-leaf green */
    --accent-dim:    #8aa964;
    --kbd-bg:        #22281f;
    --kbd-border:    #323a2e;

    --link:          #cfe5a8;

    --font-sans:     -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    --font-mono:     ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

@media (prefers-color-scheme: light) {
    :root {
        --bg:            #fbfbf8;
        --bg-panel:      #ffffff;
        --bg-card:       #ffffff;
        --border:        #e0e1dd;
        --border-soft:   #ececea;

        --text:          #1a1e1a;
        --text-muted:    #50554f;
        --text-subtle:   #7b827a;
        --text-tertiary: #9da49d;

        --accent:        #5a7f3a;
        --accent-dim:    #7a9f5a;
        --kbd-bg:        #f1f3ee;
        --kbd-border:    #d8dcd4;

        --link:          #3b5c22;
    }
}

* { box-sizing: border-box; }

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--link);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.12s ease;
}

a:hover { border-bottom-color: var(--link); }

code, kbd {
    font-family: var(--font-mono);
    font-size: 0.875em;
}

code {
    background: var(--bg-card);
    border: 1px solid var(--border-soft);
    border-radius: 3px;
    padding: 0.1em 0.35em;
}

kbd {
    background: var(--kbd-bg);
    border: 1px solid var(--kbd-border);
    border-radius: 4px;
    padding: 0.1em 0.45em;
    font-weight: 500;
    box-shadow: 0 1px 0 rgba(0,0,0,0.15);
    white-space: nowrap;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 28px;
}

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

.hero {
    padding: 88px 0 56px;
    background:
      radial-gradient(ellipse 800px 400px at 50% -100px, rgba(180, 211, 136, 0.08), transparent 60%),
      var(--bg);
    border-bottom: 1px solid var(--border-soft);
    text-align: left;
}

.wordmark {
    font-size: 56px;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin: 0 0 10px;
    color: var(--text);
}

.tagline {
    font-size: 22px;
    color: var(--text);
    font-weight: 500;
    margin: 0 0 10px;
    line-height: 1.35;
}

.lede {
    font-size: 16px;
    color: var(--text-muted);
    max-width: 640px;
    margin: 0 0 28px;
}

.cta {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 18px;
}

.btn {
    display: inline-block;
    padding: 10px 18px;
    border-radius: 6px;
    font-weight: 500;
    font-size: 14px;
    border: 1px solid var(--border);
    color: var(--text);
    background: var(--bg-card);
    transition: border-color 0.12s ease, background 0.12s ease;
}

.btn:hover {
    border-color: var(--text-muted);
    border-bottom-color: var(--text-muted);
}

.btn.primary {
    background: var(--accent);
    border-color: var(--accent);
    color: #1a1e1a;
}

.btn.primary:hover {
    background: var(--accent-dim);
    border-color: var(--accent-dim);
    border-bottom-color: var(--accent-dim);
}

.meta {
    font-size: 13px;
    color: var(--text-subtle);
    margin: 0;
}

/* ---------- Screenshot ------------------------------------------------ */

.screenshot {
    margin: 48px 0 8px;
    text-align: center;
}

.screenshot img {
    width: 100%;
    max-width: 680px;
    height: auto;
    display: inline-block;
    border-radius: 10px;
    border: 1px solid var(--border);
    box-shadow:
        0 12px 36px rgba(0, 0, 0, 0.45),
        0 2px 8px rgba(0, 0, 0, 0.3);
}

@media (prefers-color-scheme: light) {
    .screenshot img {
        box-shadow:
            0 12px 36px rgba(0, 0, 0, 0.12),
            0 2px 8px rgba(0, 0, 0, 0.06);
    }
}

@media (max-width: 640px) {
    .screenshot img { max-width: 100%; }
}

/* ---------- Sections ------------------------------------------------- */

main section {
    padding: 48px 0;
    border-bottom: 1px solid var(--border-soft);
}

main section:last-of-type { border-bottom: none; }

h2 {
    font-size: 26px;
    letter-spacing: -0.015em;
    margin: 0 0 20px;
}

h3 {
    font-size: 16px;
    font-weight: 600;
    margin: 0 0 10px;
    letter-spacing: -0.005em;
}

ul, ol { padding-left: 22px; }

li { margin-bottom: 5px; }

.subtle {
    color: var(--text-subtle);
    font-size: 14px;
    margin: 0 0 12px;
}

/* ---------- Highlights bullet list ----------------------------------- */

.highlights {
    list-style: none;
    padding: 0;
    columns: 2;
    column-gap: 36px;
}

.highlights li {
    margin-bottom: 10px;
    break-inside: avoid;
}

/* ---------- Feature grid --------------------------------------------- */

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 18px;
}

.feature {
    background: var(--bg-card);
    border: 1px solid var(--border-soft);
    border-radius: 10px;
    padding: 20px 22px;
}

.feature p:first-of-type {
    color: var(--text-muted);
    font-size: 14px;
    margin: 0 0 10px;
}

.feature ul {
    padding-left: 18px;
    margin: 0;
}

.feature li {
    font-size: 14px;
    color: var(--text);
    margin-bottom: 4px;
}

/* ---------- Placeholder reference ------------------------------------ */

.placeholders {
    display: grid;
    grid-template-columns: max-content 1fr;
    gap: 6px 18px;
    margin: 8px 0 4px;
}

.placeholders dt {
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--text);
}

.placeholders dd {
    margin: 0;
    color: var(--text-muted);
    font-size: 13px;
}

/* ---------- Keyboard cheat sheet ------------------------------------- */

.shortcuts {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

.shortcuts td {
    padding: 9px 0;
    border-bottom: 1px solid var(--border-soft);
}

.shortcuts td:first-child {
    width: 200px;
}

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

footer {
    padding: 40px 0 60px;
    border-top: 1px solid var(--border-soft);
    text-align: center;
    color: var(--text-muted);
    font-size: 13px;
}

footer p {
    margin: 4px 0;
}

.tagline-small {
    margin-top: 14px !important;
    color: var(--text-subtle);
    font-size: 12px;
}

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

@media (max-width: 640px) {
    .hero {
        padding: 56px 0 40px;
    }
    .wordmark { font-size: 44px; }
    .tagline  { font-size: 18px; }
    .lede     { font-size: 15px; }
    .highlights { columns: 1; }
    .screenshot.placeholder .screenshot-inner { height: 240px; }
    h2 { font-size: 22px; }
    .shortcuts td:first-child { width: auto; padding-right: 16px; }
    .container { padding: 0 20px; }
}