:root {
    color-scheme: light;
    --paper: #f5f1e8;
    --ink: #1c2420;
    --muted: #69716b;
    --line: #d8d5cc;
    --accent: #e25332;
    --accent-dark: #b83d24;
    --panel: #ebe7dc;
    --shadow: rgba(34, 42, 35, 0.08);
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        color-scheme: dark;
        --paper: #17201c;
        --ink: #eef1e8;
        --muted: #a7b0a6;
        --line: #36413a;
        --accent: #f47752;
        --accent-dark: #ff9574;
        --panel: #202b25;
        --shadow: rgba(0, 0, 0, 0.18);
    }
}

:root[data-theme="dark"] {
    color-scheme: dark;
    --paper: #17201c;
    --ink: #eef1e8;
    --muted: #a7b0a6;
    --line: #36413a;
    --accent: #f47752;
    --accent-dark: #ff9574;
    --panel: #202b25;
    --shadow: rgba(0, 0, 0, 0.18);
}

:root[data-theme="light"] {
    color-scheme: light;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-width: 280px;
    min-height: 100vh;
    background: var(--paper);
    color: var(--ink);
    font-family: "Avenir Next", "Trebuchet MS", sans-serif;
    transition: background 180ms ease, color 180ms ease;
}

body::before {
    position: fixed;
    inset: 0;
    z-index: -1;
    background-image: linear-gradient(rgba(105, 113, 107, .08) 1px, transparent 1px), linear-gradient(90deg, rgba(105, 113, 107, .08) 1px, transparent 1px);
    background-size: 40px 40px;
    content: "";
    mask-image: linear-gradient(to bottom, black, transparent 75%);
    pointer-events: none;
}

.app-shell {
    display: flex;
    flex-direction: column;
    width: min(100% - 48px, 1080px);
    min-height: 100vh;
    margin: 0 auto;
    padding: 28px 0 32px;
}

.topbar,
.footer-note,
.control-heading,
.result-label,
.brand,
.theme-toggle {
    display: flex;
    align-items: center;
}

.topbar,
.footer-note,
.control-heading {
    justify-content: space-between;
}

.brand {
    gap: 10px;
    color: var(--ink);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: .15em;
    text-decoration: none;
    text-transform: uppercase;
}

.brand-mark {
    display: grid;
    width: 28px;
    height: 28px;
    border: 1px solid var(--ink);
    border-radius: 50%;
    place-items: center;
    font-size: 17px;
    font-weight: 400;
}

.theme-toggle {
    gap: 9px;
    padding: 8px 12px;
    border: 1px solid var(--line);
    border-radius: 100px;
    background: transparent;
    color: var(--ink);
    cursor: pointer;
    font: inherit;
    font-size: 12px;
}

.theme-toggle:hover {
    border-color: var(--accent);
    color: var(--accent-dark);
}

.theme-icon {
    font-size: 16px;
    line-height: 1;
}

.hero {
    max-width: 700px;
    margin: auto 0 58px;
    padding-top: 12vh;
}

.eyebrow {
    margin: 0 0 20px;
    color: var(--accent-dark);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: .18em;
    text-transform: uppercase;
}

h1 {
    max-width: 700px;
    margin: 0;
    font-family: Georgia, "Times New Roman", serif;
    font-size: clamp(48px, 8vw, 94px);
    font-weight: 400;
    letter-spacing: -0.03em;
    line-height: .94;
}

h1 span {
    color: var(--accent);
    font-style: italic;
}

.intro {
    margin: 23px 0 0;
    color: var(--muted);
    font-size: 16px;
}

.converter-panel {
    display: grid;
    grid-template-columns: minmax(260px, .85fr) 1.15fr;
    gap: 7vw;
    align-items: end;
    padding: 34px 0 40px;
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
}

.result-label {
    gap: 9px;
    color: var(--muted);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: .12em;
    text-transform: uppercase;
}

.dot,
.status-light {
    display: inline-block;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent);
}

.result-value {
    display: block;
    margin-top: 18px;
    font-family: Georgia, "Times New Roman", serif;
    font-size: clamp(58px, 8vw, 100px);
    letter-spacing: -0.045em;
    line-height: .95;
}

.result-value small {
    color: var(--accent);
    font-family: "Avenir Next", "Trebuchet MS", sans-serif;
    font-size: .28em;
    font-weight: 700;
    letter-spacing: .02em;
}

.formula {
    margin: 16px 0 0;
    color: var(--muted);
    font-family: monospace;
    font-size: 12px;
}

.control-heading {
    margin-bottom: 32px;
    font-size: 15px;
    font-weight: 700;
}

.control-heading output {
    color: var(--accent-dark);
    font-family: monospace;
    font-size: 14px;
}

.slider-wrap {
    padding-bottom: 6px;
}

input[type="range"] {
    display: block;
    width: 100%;
    height: 8px;
    margin: 0;
    accent-color: var(--accent);
    cursor: pointer;
}

input[type="range"]:focus-visible {
    outline: 3px solid color-mix(in srgb, var(--accent) 40%, transparent);
    outline-offset: 8px;
}

.scale {
    display: flex;
    justify-content: space-between;
    margin-top: 14px;
    color: var(--muted);
    font-family: monospace;
    font-size: 11px;
}

.footer-note {
    margin-top: auto;
    padding-top: 22px;
    color: var(--muted);
    font-family: monospace;
    font-size: 11px;
}

.status {
    display: flex;
    align-items: center;
    gap: 8px;
}

.status-light {
    width: 6px;
    height: 6px;
    background: #5d9c72;
}

@media (max-width: 680px) {
    .app-shell {
        width: min(100% - 32px, 560px);
        padding-top: 20px;
    }

    .hero {
        margin: 88px 0 42px;
        padding-top: 0;
    }

    .converter-panel {
        display: block;
        padding: 28px 0 34px;
    }

    .control-block {
        margin-top: 46px;
    }

    .footer-note {
        align-items: flex-start;
        flex-direction: column;
        gap: 12px;
    }
}

@media (orientation: landscape) and (max-height: 620px) {
    .app-shell {
        padding-top: 18px;
    }

    .hero {
        margin: 50px 0 30px;
        padding-top: 0;
    }

    h1 {
        font-size: clamp(42px, 10vh, 72px);
    }

    .converter-panel {
        padding: 24px 0 28px;
    }

    .result-value {
        margin-top: 12px;
        font-size: clamp(52px, 12vh, 78px);
    }

    .control-heading {
        margin-bottom: 22px;
    }
}