:root {
    color-scheme: light;
    --page: #e7e2d8;
    --ink: #171a17;
    --muted: #656b63;
    --panel: #f6f2e9;
    --panel-2: #eee8dc;
    --line: #c8bead;
    --line-strong: #8f806b;
    --board: #11673e;
    --board-dark: #0d4a30;
    --accent: #8b2f23;
    --gold: #b28b45;
    --shadow: 0 18px 42px rgba(45, 37, 26, 0.18);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    overflow-x: hidden;
    color: var(--ink);
    font-family: "Yu Gothic", "Hiragino Sans", "Meiryo", system-ui, sans-serif;
    background:
        linear-gradient(90deg, rgba(23, 26, 23, 0.06) 1px, transparent 1px),
        linear-gradient(rgba(23, 26, 23, 0.04) 1px, transparent 1px),
        var(--page);
    background-size: 28px 28px;
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input {
    font: inherit;
}

button {
    min-height: 40px;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: #fffaf1;
    color: var(--ink);
    cursor: pointer;
}

button:hover,
button:focus-visible {
    border-color: var(--accent);
    outline: none;
}

.shell {
    width: min(1160px, calc(100% - 28px));
    margin: 0 auto;
    padding: 22px 0 42px;
}

.header {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 16px;
    align-items: start;
    margin-bottom: 18px;
}

.back-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 74px;
    min-height: 36px;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: rgba(255, 250, 241, 0.76);
    color: var(--muted);
}

.eyebrow {
    margin: 0 0 6px;
    color: var(--accent);
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0;
    text-transform: uppercase;
}

h1,
h2,
p {
    margin-top: 0;
}

h1 {
    margin-bottom: 8px;
    font-size: clamp(2.2rem, 5vw, 4rem);
    line-height: 1;
    letter-spacing: 0;
}

h2 {
    margin-bottom: 10px;
    font-size: 0.98rem;
}

.lead {
    max-width: 34rem;
    margin: 0;
    color: var(--muted);
    line-height: 1.7;
}

.layout {
    display: grid;
    grid-template-columns: minmax(320px, 684px) minmax(292px, 360px);
    gap: 18px;
    align-items: start;
}

.board-panel,
.panel {
    border: 1px solid var(--line);
    border-radius: 6px;
    background: rgba(246, 242, 233, 0.92);
    box-shadow: var(--shadow);
}

.board-panel {
    padding: clamp(10px, 2vw, 18px);
    overflow: hidden;
}

#boardCanvas {
    display: block;
    width: 100%;
    max-width: 640px;
    aspect-ratio: 1 / 1;
    height: auto;
    border: 10px solid #2b2218;
    border-radius: 4px;
    background: var(--board);
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.18);
}

.side {
    display: grid;
    gap: 12px;
}

.panel {
    padding: 15px;
}

.status-text,
.winner-text,
.note p,
.ranking-head span,
.ranking-list .entry span,
.ranking-list .empty,
.submit-status {
    color: var(--muted);
}

.status-text {
    min-height: 1.6em;
    margin-bottom: 12px;
    line-height: 1.55;
}

.winner-text {
    min-height: 1.4em;
    margin-bottom: 12px;
    color: var(--accent);
    font-weight: 800;
}

.score-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
}

.score-grid div {
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: var(--panel-2);
}

.score-grid span {
    display: block;
    min-height: 1.35em;
    color: var(--muted);
    font-size: 0.82rem;
}

.score-grid strong {
    display: block;
    margin-top: 4px;
    font-size: 1.8rem;
    line-height: 1;
}

.controls {
    display: grid;
    gap: 11px;
}

.segmented {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 6px;
}

.side-choice {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.difficulty-button.is-active,
.side-button.is-active {
    border-color: var(--accent);
    background: #2b2218;
    color: #fffaf1;
}

#newGameButton {
    border-color: var(--line-strong);
    background: var(--accent);
    color: #fff;
    font-weight: 800;
}

.ranking-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}

.ranking-list {
    display: grid;
    gap: 8px;
    margin: 0;
    padding-left: 1.35rem;
}

.ranking-list li {
    padding: 8px 0;
    border-top: 1px solid var(--line);
}

.ranking-list .entry {
    display: grid;
    gap: 3px;
}

.ranking-list .entry strong {
    color: var(--ink);
}

.ranking-list .entry span {
    font-size: 0.84rem;
}

.score-form {
    display: grid;
    gap: 8px;
    margin-top: 14px;
}

.score-form[hidden] {
    display: none;
}

.submit-row {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 8px;
}

.submit-row input {
    min-width: 0;
    min-height: 40px;
    padding: 0 10px;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: #fffaf1;
    color: var(--ink);
}

.note p {
    margin-bottom: 0;
    line-height: 1.7;
}

@media (max-width: 900px) {
    .layout {
        grid-template-columns: 1fr;
    }

    .side {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 640px) {
    .shell {
        width: min(100% - 18px, 520px);
        padding-top: 14px;
    }

    .header,
    .side {
        grid-template-columns: 1fr;
    }

    .back-link {
        width: fit-content;
    }

    .segmented,
    .side-choice {
        grid-template-columns: 1fr;
    }

    .board-panel {
        padding: 8px;
    }

    #boardCanvas {
        border-width: 6px;
    }

    .score-grid,
    .submit-row {
        grid-template-columns: 1fr;
    }

    h1 {
        font-size: clamp(2rem, 12vw, 3rem);
    }
}