* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

body {
    transition: background-color 0.3s, color 0.3s;
    min-height: 100vh;
}

body.day-mode {
    background-color: #f5f6f8;
    color: #333;
}

body.night-mode {
    background-color: #1a1b1e;
    color: #e0e0e0;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding: 10px 0;
}

h1 {
    font-size: 24px;
    font-weight: 500;
}

.theme-buttons {
    display: flex;
    gap: 10px;
}

.theme-btn {
    padding: 6px 16px;
    border: 1px solid #ddd;
    background: transparent;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    color: inherit;
}

body.night-mode .theme-btn {
    border-color: #444;
}

.game-container {
    display: flex;
    gap: 30px;
    align-items: flex-start;
}

.board-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.board-container {
    background: #deb887;
    padding: 15px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

body.night-mode .board-container {
    background: #a67b5b;
}

#board {
    display: block;
    width: 100%;
    max-width: 600px;
    height: auto;
}

.coordinates-toggle {
    margin-top: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.toggle-label {
    font-size: 14px;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 40px;
    height: 20px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    border-radius: 20px;
    transition: .3s;
}

body.night-mode .toggle-slider {
    background-color: #555;
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 14px;
    width: 14px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    border-radius: 50%;
    transition: .3s;
}

input:checked + .toggle-slider {
    background-color: #007bff;
}

input:checked + .toggle-slider:before {
    transform: translateX(20px);
}

.controls {
    width: 340px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.score-display {
    display: flex;
    gap: 15px;
}

.player {
    flex: 1;
    padding: 20px 10px;
    text-align: center;
    border-radius: 4px;
    border: 1px solid transparent;
}

.player.black {
    background-color: #1a1a1a;
    color: #fff;
}

.player.white {
    background-color: #fff;
    color: #333;
    border-color: #ddd;
}

body.night-mode .player.white {
    background-color: #2c2c2c;
    color: #fff;
    border-color: #444;
}

.player.current-player {
    border-color: #007bff;
    box-shadow: 0 0 0 2px rgba(0,123,255,0.2);
}

.player-title {
    font-size: 14px;
    margin-bottom: 10px;
}

.timer {
    font-size: 20px;
    font-family: monospace;
    font-weight: bold;
    margin-bottom: 15px;
}

.stats {
    display: flex;
    flex-direction: column;
    gap: 5px;
    font-size: 12px;
    color: #aaa;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.btn-row {
    display: flex;
    gap: 8px;
}

.diff-btn, .rule-btn, .action-btn {
    flex: 1;
    padding: 10px;
    border: 1px solid #ddd;
    background: transparent;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    color: inherit;
}

body.night-mode .diff-btn, 
body.night-mode .rule-btn, 
body.night-mode .action-btn {
    border-color: #444;
}

.btn-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.full-width {
    width: 100%;
}

.diff-btn.active, .rule-btn.active {
    background-color: #007bff;
    color: white;
    border-color: #007bff;
}

.time-settings {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.time-title {
    font-size: 14px;
    color: #666;
}

body.night-mode .time-title {
    color: #aaa;
}

.time-inputs {
    display: flex;
    gap: 10px;
}

.time-input {
    flex: 1;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    text-align: center;
    background: transparent;
    color: inherit;
}

body.night-mode .time-input {
    border-color: #444;
}

.game-status {
    padding: 15px;
    text-align: center;
    font-size: 13px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

body.night-mode .game-status {
    border-color: #444;
}

.footer {
    margin-top: 50px;
    text-align: center;
    font-size: 13px;
    color: #888;
    padding-bottom: 20px;
}

@media (max-width: 900px) {
    .game-container {
        flex-direction: column;
        align-items: center;
    }
    .controls {
        width: 100%;
        max-width: 600px;
    }
}