:root {
    --background: #151515;
    --surface: #202020;
    --surface-hover: #8b3a3a;

    --text: #e8e8e8;
    --text-muted: #999;

    --border: #383838;
    --border-hover: #8b3a3a;

    --max-width: 1080px;
}


/* Base
-------------------------------------------------- */

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--background);
    color: var(--text);

    font-family:
        -apple-system,
        BlinkMacSystemFont,
        "Helvetica Neue",
        "Hiragino Kaku Gothic ProN",
        "Hiragino Sans",
        "Yu Gothic",
        YuGothic,
        Meiryo,
        sans-serif;

    font-size: 16px;
    line-height: 1.8;
}

a {
    color: inherit;
}


/* Header
-------------------------------------------------- */

.site-header {
    border-bottom: 1px solid var(--border);
    background: var(--background);
}

.site-header__inner {
    width: min(calc(100% - 40px), var(--max-width));
    margin: 0 auto;
    padding: 30px 0;
}

.site-title {
    display: inline-block;
    color: var(--text);
    font-size: 2rem;
    font-weight: 500;
    line-height: 1.3;
    letter-spacing: .04em;
    text-decoration: none;
}

.site-title:hover,
.site-title:focus-visible {
    color: #fff;
}


/* Main
-------------------------------------------------- */

.main {
    width: min(calc(100% - 40px), var(--max-width));
    margin: 0 auto;
    padding: 60px 0 80px;
}


/* Page Header
-------------------------------------------------- */

.page-header {
    margin-bottom: 52px;
}

.page-header h1 {
    margin: 0;
    color: var(--text);
    font-size: clamp(2rem, 5vw, 2.8rem);
    font-weight: 500;
    line-height: 1.3;
    letter-spacing: .02em;
}

.page-header h1::after {
    content: "";
    display: block;
    width: 36px;
    height: 2px;
    margin-top: 16px;
    background: var(--text);
}

.page-header > p:not(.thanks) {
    max-width: 700px;
    margin: 18px 0 0;
    color: var(--text-muted);
    font-size: .9rem;
}


/* Special Thanks
-------------------------------------------------- */

.thanks {
    margin: 24px 0 0;
    color: var(--text-muted);
    font-size: .82rem;
    font-style: italic;
}

.thanks a {
    text-decoration: underline;
    text-underline-offset: 3px;
}

.thanks a:hover,
.thanks a:focus-visible {
    color: #fff;
}


/* Section
-------------------------------------------------- */

.section {
    margin-top: 56px;
}

.section-header {
    display: flex;
    align-items: baseline;
    gap: 14px;
    margin-bottom: 18px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border);
}

.section-header h2 {
    margin: 0;
    color: var(--text);
    font-size: 1.25rem;
    font-weight: 500;
    letter-spacing: .03em;
}

.section-header span {
    color: var(--text-muted);
    font-size: .75rem;
}


/* Link Cards
-------------------------------------------------- */

.link-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

.link-card {
    display: flex;
    align-items: center;
    justify-content: space-between;

    min-height: 82px;
    padding: 20px 22px;

    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);

    font-size: .95rem;
    font-weight: 500;
    text-decoration: none;

    transition:
        background-color .18s ease,
        border-color .18s ease,
        color .18s ease;
}

.link-card span:last-child {
    color: var(--text-muted);
    font-size: 1rem;

    transition:
        color .18s ease,
        transform .18s ease;
}

.link-card:hover,
.link-card:focus-visible {
    border-color: var(--border-hover);
    background: var(--surface-hover);
    color: #fff;
}

.link-card:hover span:last-child,
.link-card:focus-visible span:last-child {
    color: #fff;
    transform: translateX(3px);
}


/* Song Index
-------------------------------------------------- */

.section--song-index {
    margin-top: 64px;
}

.song-index {
    width: 100%;
}


/* Note
-------------------------------------------------- */

.note {
    margin: 48px 0 0;
    padding: 16px 18px;

    border-left: 2px solid #555;
    background: #1c1c1c;

    color: var(--text-muted);
    font-size: .78rem;
}


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

.site-footer {
    border-top: 1px solid var(--border);
    background: var(--background);
}

.site-footer__inner {
    width: min(calc(100% - 40px), var(--max-width));
    margin: 0 auto;
    padding: 28px 0 34px;

    color: var(--text-muted);
    font-size: .72rem;
}

.site-footer p {
    margin: 0;
}

.site-footer p + p {
    margin-top: 5px;
}


/* Tablet
-------------------------------------------------- */

@media (max-width: 800px) {

    .link-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}


/* Smartphone
-------------------------------------------------- */

@media (max-width: 600px) {

    .site-header__inner,
    .main,
    .site-footer__inner {
        width: min(calc(100% - 28px), var(--max-width));
    }

    .site-header__inner {
        padding: 22px 0;
    }

    .site-title {
        font-size: 1.7rem;
    }

    .main {
        padding: 42px 0 58px;
    }

    .page-header {
        margin-bottom: 40px;
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .section {
        margin-top: 44px;
    }

    .link-grid {
        gap: 9px;
    }

    .link-card {
        min-height: 72px;
        padding: 16px;
        font-size: .88rem;
    }

    .section--song-index {
        margin-top: 48px;
    }
}


/* Very small screens
-------------------------------------------------- */

@media (max-width: 380px) {

    .link-grid {
        grid-template-columns: 1fr;
    }
}


/* Accessibility
-------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {

    html {
        scroll-behavior: auto;
    }

    .link-card,
    .link-card span:last-child {
        transition: none;
    }
}