:root {
    --editorial-bg: #1d1d1b;
    --editorial-surface: #242421;
    --editorial-text: #f1f0ea;
    --editorial-muted: #9b9990;
    --editorial-soft: #c7c2b7;
    --editorial-rule: #3c3b36;
    --editorial-accent: #e8e0d0;
    --board-surface: #242421;
    --mark-x: #f1f0ea;
    --mark-o: #c7c2b7;
    --sidebar-width: 312px;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    min-height: 100vh;
    min-height: 100svh;
    color: var(--editorial-text);
    background:
        radial-gradient(circle at 76% 14%, rgba(232, 224, 208, 0.06), transparent 28rem),
        var(--editorial-bg);
    font-family: 'Newsreader', Georgia, serif;
    font-size: 19px;
    line-height: 1.65;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    transition: background 180ms ease, color 180ms ease;
}

body.light-theme {
    --editorial-bg: #f1f0ea;
    --editorial-surface: #e8e0d0;
    --editorial-text: #1d1d1b;
    --editorial-muted: #6f6b60;
    --editorial-soft: #3c3b36;
    --editorial-rule: #c7c2b7;
    --editorial-accent: #1d1d1b;
    --board-surface: #f7f3ea;
    --mark-x: #1d1d1b;
    --mark-o: #6f6b60;
}

.app {
    min-height: 100vh;
    min-height: 100svh;
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr;
    gap: 28px;
    padding: 28px;
}

.sidebar {
    min-height: calc(100svh - 56px);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 28px;
    padding: 4px 0;
    border-right: 1px solid var(--editorial-rule);
}

.kicker {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 0 0 26px;
    color: var(--editorial-muted);
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.18em;
    line-height: 1.2;
    text-transform: uppercase;
}

.kicker span {
    width: 34px;
    height: 1px;
    background: var(--editorial-muted);
    display: inline-block;
}

h1 {
    margin: 0;
    max-width: 240px;
    color: var(--editorial-text);
    font-family: 'Newsreader', Georgia, serif;
    font-size: clamp(3rem, 6vw, 5rem);
    font-weight: 700;
    letter-spacing: -0.055em;
    line-height: 0.95;
}

.subtitle {
    margin: 20px 0 30px;
    max-width: 250px;
    color: var(--editorial-soft);
    font-size: 1.08rem;
    font-style: italic;
    line-height: 1.42;
}

#game-status {
    margin: 0;
    padding-top: 20px;
    border-top: 1px solid var(--editorial-rule);
    color: var(--editorial-accent);
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.14em;
    line-height: 1.45;
    text-transform: uppercase;
    min-height: 58px;
}

.sidebar-bottom {
    padding-right: 28px;
}

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

button {
    width: 100%;
    height: 56px;
    border: 1px solid var(--editorial-rule);
    border-radius: 0;
    padding: 0 16px;
    color: var(--editorial-text);
    background: transparent;
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.13em;
    line-height: 56px;
    text-align: center;
    text-transform: uppercase;
    cursor: pointer;
    transition: background 180ms ease, color 180ms ease, border-color 180ms ease, transform 180ms ease;
}

#start-button {
    border-color: var(--editorial-accent);
    color: var(--editorial-bg);
    background: var(--editorial-accent);
}

button:hover,
button:focus {
    border-color: var(--editorial-accent);
}

button:hover:not(#start-button),
button:focus:not(#start-button) {
    color: var(--editorial-bg);
    background: var(--editorial-accent);
}

button:active { transform: translateY(1px); }

.board-wrap {
    min-width: 0;
    min-height: calc(100svh - 56px);
    display: grid;
    place-items: center;
}

#game-board {
    position: relative;
    width: min(calc(100vw - var(--sidebar-width) - 84px), calc(100svh - 56px), 680px);
    height: min(calc(100vw - var(--sidebar-width) - 84px), calc(100svh - 56px), 680px);
    min-width: 280px;
    min-height: 280px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    border: 1px solid var(--editorial-rule);
    background: var(--board-surface);
    box-shadow: 0 32px 90px rgba(0, 0, 0, 0.28);
}

.cell {
    position: relative;
    z-index: 1;
    width: 100%;
    height: 100%;
    border: 0;
    border-right: 1px solid var(--editorial-rule);
    border-bottom: 1px solid var(--editorial-rule);
    display: grid;
    place-items: center;
    color: var(--editorial-text);
    background: transparent;
    font-family: 'Inter', system-ui, sans-serif;
    font-size: clamp(3.3rem, 13vmin, 8rem);
    font-weight: 800;
    line-height: 1;
    cursor: pointer;
    transition: background 140ms ease, color 140ms ease;
}

.cell:nth-child(3n) { border-right: 0; }
.cell:nth-child(n + 7) { border-bottom: 0; }

.cell:hover {
    background: rgba(232, 224, 208, 0.08);
}

.cell:empty::after {
    content: '';
    width: 10px;
    height: 10px;
    border-radius: 999px;
    background: var(--editorial-rule);
    opacity: 0;
    transition: opacity 140ms ease;
}

.cell:empty:hover::after { opacity: 1; }

.cell.x-mark {
    color: var(--mark-x);
}

.cell.o-mark {
    color: var(--mark-o);
}

#win-line {
    position: absolute;
    z-index: 3;
    top: 50%;
    left: 50%;
    width: 88%;
    height: 7px;
    border-radius: 999px;
    background: var(--editorial-accent);
    box-shadow: 0 0 0 1px var(--editorial-bg), 0 10px 28px rgba(0, 0, 0, 0.28);
    opacity: 0;
    pointer-events: none;
    transform: translate(-50%, -50%) scaleX(0);
    transform-origin: center;
    transition: opacity 180ms ease, transform 360ms ease;
}

#game-board.has-win #win-line {
    opacity: 1;
    transform: translate(-50%, -50%) scaleX(1);
}

#game-board.has-win #win-line.row-0 { top: 16.666%; }
#game-board.has-win #win-line.row-1 { top: 50%; }
#game-board.has-win #win-line.row-2 { top: 83.333%; }
#game-board.has-win #win-line.col-0 { left: 16.666%; transform: translate(-50%, -50%) rotate(90deg) scaleX(1); }
#game-board.has-win #win-line.col-1 { left: 50%; transform: translate(-50%, -50%) rotate(90deg) scaleX(1); }
#game-board.has-win #win-line.col-2 { left: 83.333%; transform: translate(-50%, -50%) rotate(90deg) scaleX(1); }
#game-board.has-win #win-line.diag-main { width: 122%; transform: translate(-50%, -50%) rotate(45deg) scaleX(1); }
#game-board.has-win #win-line.diag-anti { width: 122%; transform: translate(-50%, -50%) rotate(-45deg) scaleX(1); }

.cell.winner {
    animation: winPulse 1.5s ease-in-out infinite;
    background: rgba(232, 224, 208, 0.12);
}

.result-modal {
    position: fixed;
    z-index: 20;
    inset: 0;
    display: grid;
    place-items: center;
    padding: 24px;
    background: rgba(29, 29, 27, 0.72);
    opacity: 0;
    pointer-events: none;
    transition: opacity 180ms ease;
}

.result-modal.show {
    opacity: 1;
    pointer-events: auto;
}

.result-card {
    width: min(420px, 100%);
    padding: 30px;
    border: 1px solid var(--editorial-rule);
    background: var(--editorial-bg);
    box-shadow: 0 32px 90px rgba(0, 0, 0, 0.36);
}

.result-card .kicker { margin-bottom: 18px; }

.result-card h2 {
    margin: 0 0 28px;
    color: var(--editorial-text);
    font-family: 'Newsreader', Georgia, serif;
    font-size: clamp(2.2rem, 6vw, 3.6rem);
    font-weight: 700;
    letter-spacing: -0.045em;
    line-height: 0.95;
}

@keyframes winPulse {
    0%, 100% {
        box-shadow: inset 0 0 0 0 rgba(232, 224, 208, 0.0);
    }
    50% {
        box-shadow: inset 0 0 0 8px rgba(232, 224, 208, 0.18);
    }
}

@media (max-width: 820px) {
    .app {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr;
        gap: 14px;
        padding: 14px;
    }

    .sidebar {
        min-height: auto;
        display: grid;
        grid-template-columns: 1fr;
        gap: 14px;
        padding: 0 0 14px;
        border-right: 0;
        border-bottom: 1px solid var(--editorial-rule);
    }

    .kicker,
    .subtitle { display: none; }

    h1 {
        max-width: none;
        font-size: 2.4rem;
    }

    #game-status {
        margin-top: 10px;
        padding-top: 10px;
        min-height: auto;
    }

    .sidebar-bottom { padding-right: 0; }

    .controls {
        grid-template-columns: repeat(3, 1fr);
    }

    button {
        height: 48px;
        line-height: 48px;
        padding: 0 10px;
        letter-spacing: 0.08em;
    }

    .board-wrap { min-height: auto; }

    #game-board {
        width: min(calc(100vw - 28px), calc(100svh - 190px));
        height: min(calc(100vw - 28px), calc(100svh - 190px));
    }
}

@media (max-width: 560px) {
    body { font-size: 17px; }

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

    #game-board {
        width: min(calc(100vw - 28px), calc(100svh - 250px));
        height: min(calc(100vw - 28px), calc(100svh - 250px));
    }
}