:root {
    --bg: #0b1020;
    --panel: rgba(255, 255, 255, 0.06);
    --panel-border: rgba(255, 255, 255, 0.1);
    --text: #e5e7eb;
    --muted: rgba(229, 231, 235, 0.7);
    --primary: #8b5cf6; /* purple */
    --danger: #ef4444; /* red */
    --btn: rgba(255, 255, 255, 0.08);
    --btn-hover: rgba(255, 255, 255, 0.14);
    --shadow: 0 18px 60px rgba(0, 0, 0, 0.45);
}

* {
    box-sizing: border-box;
}

html,
body {
    height: 100%;
}

body {
    margin: 0;
    background:
        radial-gradient(
            1200px 800px at 75% 40%,
            rgba(139, 92, 246, 0.16),
            transparent 60%
        ),
        radial-gradient(
            1200px 800px at 25% 70%,
            rgba(239, 68, 68, 0.1),
            transparent 55%
        ),
        var(--bg);
    color: var(--text);
    font-family:
        ui-sans-serif,
        system-ui,
        -apple-system,
        Segoe UI,
        Roboto,
        Helvetica,
        Arial,
        'Apple Color Emoji',
        'Segoe UI Emoji';
}

#app {
    display: flex;
    height: 100vh;
    width: 100%;
}

#sidebar {
    width: 320px;
    padding: 18px 16px;
    border-right: 1px solid var(--panel-border);
    background: rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(12px);
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.brand-title {
    font-size: 22px;
    font-weight: 700;
    letter-spacing: 0.2px;
}

.brand-version {
    margin-top: 6px;
    color: var(--muted);
    font-size: 13px;
}

.panel {
    border: 1px solid var(--panel-border);
    background: var(--panel);
    border-radius: 14px;
    padding: 14px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    display: flex;
    flex-direction: column;
    gap: 12px;
    font-size: 18px;
}

.hud-line {
    font-size: 18px;
    color: var(--muted);
    min-height: 18px;
}

.seed-field label {
    display: block;
    font-size: 18px;
    color: var(--muted);
    margin-bottom: 6px;
}

.seed-field input {
    width: 100%;
    padding: 10px 12px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: rgba(0, 0, 0, 0.25);
    color: var(--text);
    font-size: 18px;
    outline: none;
}

.seed-field input:focus {
    border-color: rgba(139, 92, 246, 0.65);
    box-shadow: 0 0 0 4px rgba(139, 92, 246, 0.14);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: var(--btn);
    color: var(--text);
    cursor: pointer;
    font-weight: 600;
    font-size: 18px;
    letter-spacing: 0.2px;
    user-select: none;
}

.btn:hover {
    background: var(--btn-hover);
}

.btn-primary {
    border-color: rgba(139, 92, 246, 0.5);
    background: rgba(139, 92, 246, 0.2);
}

.btn-primary:hover {
    background: rgba(139, 92, 246, 0.28);
}

.btn-secondary {
    border-color: rgba(255, 255, 255, 0.12);
}

.btn-icon {
    width: 18px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    opacity: 0.9;
}

.score {
    display: grid;
    gap: 6px;
    margin-top: 4px;
}

.score-line {
    font-size: 18px;
    color: var(--muted);
}

.score-line.player strong,
.score-line.player {
    color: rgba(139, 92, 246, 0.9);
}

.score-line.computer strong,
.score-line.computer {
    color: rgba(239, 68, 68, 0.95);
}

.status-bar {
    margin-top: 6px;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    height: 34px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 10px;
}

.mute-button {
    width: 34px;
    height: 34px;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: rgba(0, 0, 0, 0.22);
}

#gameArea {
    flex: 1;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 18px;
}

#gameCanvas {
    width: 100%;
    height: 100%;
    max-width: 1100px;
    max-height: 820px;
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: rgba(0, 0, 0, 0.25);
    box-shadow: var(--shadow);
}

#gameOverlay {
    position: absolute;
    inset: 18px;
    display: none;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(6px);
    border-radius: 16px;
    z-index: 1000;
}

.modal {
    width: min(520px, calc(100% - 28px));
    border-radius: 18px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: rgba(20, 24, 40, 0.92);
    box-shadow: var(--shadow);
    padding: 18px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.modal-title {
    font-size: 22px;
    font-weight: 800;
}

.modal-subtitle {
    color: var(--muted);
    font-size: 18px;
}

.modal .seed-field {
    margin-top: 4px;
}

@media (max-width: 860px) {
    #app {
        flex-direction: column;
    }
    #sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--panel-border);
    }
    #gameArea {
        padding: 12px;
    }
    #gameOverlay {
        inset: 12px;
    }
    #gameCanvas {
        max-width: none;
        max-height: none;
    }
}

/* Legacy */
.overlay {
    display: none;
}