/* Kontrail. The sky follows the time of day on your device: a daytime blue in light mode, the
   Aerodex night in dark mode, with the logo's four contrails across it. */

:root {
    --sky-top: #6fa8dc;
    --sky-low: #cfe4f5;
    --bg: #f3f8fc;
    --surface: #ffffff;
    --text: #10233f;
    --text-2: #4a5d78;
    --border: rgba(16, 35, 63, 0.12);
    --link: #1f5fbf;
    color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
    :root {
        --sky-top: #0b1630;
        --sky-low: #070c1a;
        --bg: #04070f;
        --surface: #0d1526;
        --text: #ffffff;
        --text-2: rgba(235, 240, 255, 0.7);
        --border: rgba(235, 240, 255, 0.12);
        --link: #6fb2ff;
    }
    .brand .mark { box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.2); }
    .sky-trail { opacity: 0.6; }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: Urbanist, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 18px;
    font-weight: 470;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
:focus-visible { outline: 2px solid var(--link); outline-offset: 3px; border-radius: 6px; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 16px; }

h2 {
    margin: 0 0 32px;
    font-size: clamp(30px, 4.4vw, 44px);
    line-height: 1.1;
    letter-spacing: -0.02em;
    font-weight: 750;
}

/* Top bar: over the sky until you scroll past it. */

.nav {
    position: sticky;
    top: 0;
    z-index: 10;
    background: color-mix(in srgb, var(--sky-top) 72%, transparent);
    backdrop-filter: saturate(160%) blur(18px);
    -webkit-backdrop-filter: saturate(160%) blur(18px);
}
.nav .wrap { display: flex; align-items: center; justify-content: space-between; height: 60px; }

.brand { display: flex; align-items: center; gap: 10px; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand .mark { display: block; width: 32px; height: 32px; border-radius: 7px; }
.brand .wordmark { font-size: 24px; font-weight: 800; letter-spacing: -0.02em; line-height: 1; }

.nav-links { display: flex; gap: 24px; font-size: 16px; font-weight: 600; }
.nav-links a { color: var(--text); opacity: 0.8; }
.nav-links a:hover { opacity: 1; text-decoration: none; }

/* Hero: the sky, with the trail across it. */

.hero {
    position: relative;
    overflow: hidden;
    margin-top: -60px;
    background: linear-gradient(180deg, var(--sky-top) 0, var(--sky-low) 78%, var(--bg) 100%);
}

.sky-trail { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; }
.sky-trail { opacity: 0.9; }

.hero-copy {
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: min(88vh, 760px);
    padding-top: 120px;
    padding-bottom: 96px;
}

.hero h1 {
    max-width: 9em;
    margin: 0;
    font-size: clamp(46px, 7.4vw, 92px);
    line-height: 0.98;
    letter-spacing: -0.035em;
    font-weight: 800;
}

.lede {
    max-width: 30em;
    margin: 28px 0 0;
    font-size: clamp(19px, 2vw, 22px);
    line-height: 1.5;
    color: var(--text-2);
}

/* Sections */

section { padding: 88px 0; }

/* Apps: a wide photo beside each, alternating sides. */

.app {
    display: grid;
    grid-template-columns: 1.25fr 1fr;
    align-items: center;
    gap: 48px;
    margin-bottom: 72px;
}
.app:nth-of-type(even) .shot { order: 2; }

.shot {
    display: block;
    aspect-ratio: 16 / 10;
    border-radius: 24px;
    overflow: hidden;
    background: var(--surface);
    box-shadow: 0 0 0 1px var(--border), 0 24px 48px -24px rgba(16, 35, 63, 0.35);
}
.shot img { display: block; width: 100%; height: 100%; object-fit: cover; }
.shot.pair { display: grid; grid-template-rows: 1fr 1fr; gap: 3px; background: var(--border); }
.shot.pair img { min-height: 0; }

.app-copy .icon {
    display: block;
    width: 64px;
    height: 64px;
    margin-bottom: 18px;
    border-radius: 15px;
    box-shadow: 0 0 0 1px var(--border);
}
.app h3 { margin: 0 0 8px; font-size: 32px; line-height: 1.1; letter-spacing: -0.02em; font-weight: 750; }
.app p { margin: 0; color: var(--text-2); max-width: 28em; }
.app .status { margin-top: 12px; font-size: 16px; font-weight: 600; color: var(--text); }
.go { display: inline-block; margin-top: 20px; font-weight: 700; }

/* The next app: an empty slot in the dashes of a trail still being drawn. */

.next {
    margin: 0;
    padding: 28px 32px;
    border: 2px dashed var(--border);
    border-radius: 24px;
    color: var(--text-2);
    font-size: 20px;
    text-align: center;
}

/* Promise */

.promise { background: var(--surface); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.promise dl { display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; margin: 0; }
.promise dt { font-size: 22px; font-weight: 750; letter-spacing: -0.01em; }
.promise dt::before {
    content: "";
    display: block;
    width: 36px;
    height: 4px;
    margin-bottom: 16px;
    border-radius: 2px;
    background: linear-gradient(90deg, transparent, var(--link));
}
.promise dd { margin: 6px 0 0; color: var(--text-2); }

/* Footer */

footer { padding: 28px 0 48px; border-top: 1px solid var(--border); font-size: 15px; color: var(--text-2); }
footer .wrap { display: flex; flex-wrap: wrap; gap: 12px 24px; justify-content: space-between; }
footer nav { display: flex; flex-wrap: wrap; gap: 8px 20px; }
footer a { color: var(--text-2); }
footer a:hover { color: var(--text); }

/* The 404 page */

.lost { padding: 140px 16px 120px; }
.lost h1 { margin: 0 0 12px; font-size: clamp(40px, 6vw, 64px); letter-spacing: -0.03em; line-height: 1; }
.lost p { margin: 0; font-size: 20px; color: var(--text-2); }

/* Phones */

@media (max-width: 760px) {
    body { font-size: 17px; }
    .nav-links { gap: 18px; font-size: 15px; }
    .hero-copy { justify-content: flex-end; min-height: 640px; padding-bottom: 56px; }
    .sky-trail { height: 62%; }
    section { padding: 64px 0; }
    .app { grid-template-columns: 1fr; gap: 24px; margin-bottom: 56px; }
    .app:nth-of-type(even) .shot { order: 0; }
    .promise dl { grid-template-columns: 1fr; gap: 28px; }
    .next { padding: 22px; font-size: 18px; }
}