styles.css

body {
    background-color: #121212;
    color: #ffffff;
    font-family: Arial, sans-serif;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0;
    transition: background-color 0.3s, color 0.3s;
    padding-bottom: 20px;;
}

.top-right-controls {
    position: absolute;
    top: 20px;
    right: 20px;
    display: flex;
    align-items: center;
}

.icon {
    font-size: 24px;
    cursor: pointer;
    margin-right: 10px;
}

.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}

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

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #3498db;
    transition: .4s;
    border-radius: 28px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked+.slider {
    background-color: #2c3e50;
}

input:checked+.slider:before {
    transform: translateX(22px);
}

.sun-icon,
.moon-icon {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    font-size: 12px;
    transition: .4s;
}

.sun-icon {
    left: 6px;
    color: #f1c40f;
    opacity: 0;
}

.moon-icon {
    right: 6px;
    color: #f1c40f;
    opacity: 1;
}

input:checked+.slider .sun-icon {
    opacity: 1;
}

input:checked+.slider .moon-icon {
    opacity: 0;
}

#game-container {
    position: relative;
    width: 300px;
    height: 300px;
}

#board {
    /* position: absolute; */
    top: 0;
    left: 0;
    display: grid;
    margin: 0 auto;
    grid-template-columns: repeat(3, 100px);
    gap: 0px 2px;
    width: 100%;
    height: 100%;
}

.cell {
    width: calc(300px / var(--board-size));
    height: calc(300px / var(--board-size));
    padding-bottom: 0px;
    border: 2px solid #ffffff;
    background-color: #1e1e1e;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.1s;
}

.cell:hover {
    background-color: #2e2e2e;
    transform: scale(1.05);
    z-index: 1;
}

.cell svg {
    width: 80%;
    height: 80%;
}

button {
    background-color: #6200ea;
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 18px;
    cursor: pointer;
    border-radius: 5px;
    transition: background-color 0.3s, transform 0.1s;
    margin: 5px;
}

button:hover {
    background-color: #3700b3;
    transform: scale(1.05);
}

button.selected {
    background-color: #3700b3;
    border: 2px solid #bb86fc;
    box-shadow: 0 0 10px #bb86fc;
}

.player-mode-buttons {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 20px;
}

.symbol-choice {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
}

.symbol-button {
    width: 60px;
    height: 60px;
    background-color: transparent;
    border: 2px solid #ffffff;
    border-radius: 5px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
}

.symbol-button svg {
    width: 80%;
    height: 80%;
}

.symbol-button.selected {
    box-shadow: 0 0 10px #bb86fc;
}

.symbol-button:hover {
    transform: scale(1.05);
}

.symbol-button .o-symbol,
.symbol-button .x-symbol {
    stroke-width: 8;
    transition: stroke-width 0.3s ease;
}

.symbol-button.selected .o-symbol,
.symbol-button.selected .x-symbol {
    stroke-width: 12;
}

.symbol-button .o-symbol {
    stroke: #e74c3c;
    fill: none;
}

.symbol-button .x-symbol {
    stroke: #3498db;
    stroke-linecap: round;
}

.cell .o-symbol {
    stroke: #e74c3c;
    stroke-width: 12;
    fill: none;
}

.cell .x-symbol {
    stroke: #3498db;
    stroke-width: 12;
    stroke-linecap: round;
}

.cell.selected {
    border: 2px solid #ffff00;
    z-index: 1;
}

body.light {
    background-color: #f0f0f0;
    color: #121212;
}

body.light .cell {
    border-color: #121212;
    background-color: #e0e0e0;
}

body.light .cell:hover {
    background-color: #d0d0d0;
}

body.light .cell.selected {
    border: 2px solid #ff8c00;
    z-index: 1;
}

body.light button {
    background-color: #4a90e2;
    color: white;
}

body.light button:hover {
    background-color: #3a78c2;
}

body.light button.selected {
    background-color: #3a78c2;
    border: 2px solid #4a90e2;
    box-shadow: 0 0 10px #4a90e2;
}

body.light .symbol-button {
    border-color: #121212;
}

body.light .symbol-button.selected {
    background-color: #e6f2ff;
    box-shadow: 0 0 10px #4a90e2;
}

body:not(.light) .symbol-button.selected {
    background-color: #4a00b3;
    /* Légèrement plus clair que #3700b3 */
}

@keyframes pulsate {
    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }

    100% {
        transform: scale(1);
    }
}

.winning-cell svg {
    animation: pulsate 0.5s infinite;
}

#message {
    display: flex;
    position: relative;
    text-align: center;
    align-items: center;
    justify-content: center;
    padding-top: 10px;
}

.popup {
    display: none;
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.4);
}

.popup-content {
    background-color: #fefefe;
    margin: 15% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    text-align: left;
}

.popup-content h2 {
    text-align: center;
    margin-bottom: 20px;
}

.popup-content ul {
    padding-left: 20px;
    margin-bottom: 20px;
}

.popup-content li {
    margin-bottom: 10px;
}

body.dark .popup-content {
    background-color: #333;
    color: #fff;
}

#closePopup {
    display: block;
    margin: 0 auto;
    padding: 10px 20px;
    border: none;
    cursor: pointer;
}

.numpad-layout {
    margin: 20px auto;
    border-collapse: collapse;
}

.numpad-layout td {
    width: 40px;
    height: 40px;
    text-align: center;
    border: 1px solid #ccc;
    font-weight: bold;
}

body.dark .numpad-layout td {
    border-color: #555;
}

#languageSelect {
    margin-right: 10px;
    padding: 5px;
    background-color: #6200ea;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

body.light #languageSelect {
    background-color: #4a90e2;
}

.firework {
    position: fixed;
    width: 0;
    height: 0;
    pointer-events: none;
    z-index: 9999;
}

.particle {
    position: absolute;
    width: 10px;
    height: 10px;
    transform: translate(-50%, -50%);
}

@media (max-width: 768px) {
    body {
      display: flex;
      flex-direction: column;
    }
  
    .top-right-controls {
      position: relative;
      display: inline-flex;
      justify-content: center;
      margin-bottom: 10px;
    }
  
    h1 {
      font-size: 24px;
      margin-bottom: 10px;
    }
  
    button {
      font-size: 14px;
      padding: 8px 16px;
    }
  
    #playerOptions {
      display: flex;
      flex-direction: column;
      align-items: center;
    }
  
    .symbol-choice {
      margin-bottom: 10px;
    }
  
    #resetBtn {
      margin-top: 10px;
    }
  }