* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f4f4f9;
    color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    display: flex;
    flex-direction: column;
    width: 600px;
    max-width: 95vw;
    background: white;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    overflow: hidden;
    position: relative;
}

/* Cabecera superior */
.header {
    background: #2c3e50;
    color: white;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.header h1 {
    font-size: 2.5rem;
    letter-spacing: 2px;
}

#btn-lang {
    position: absolute;
    top: 20px;
    right: 20px;
    background: #34495e;
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: background 0.3s;
    z-index: 10;
}

#btn-lang:hover {
    background: #3498db;
}

nav {
    display: flex;
    gap: 15px;
}

nav button, #btn-restart {
    padding: 10px 20px;
    background: #34495e;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.3s;
}

nav button:hover, #btn-restart:hover {
    background: #465c71;
}

nav button.active {
    background: #3498db;
}

/* Área principal */
.content {
    flex: 1;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hidden {
    display: none !important;
}

/* Estilos para el contenedor de dificultad */
#difficulty-container {
display: flex;
flex-direction: column;
align-items: center;
width: 100%;
max-width: 335px;
gap: 10px;
padding: 12px;
background: #ecf0f1;
border-radius: 5px;
}

#difficulty-label {
font-weight: bold;
color: #2c3e50;
font-size: 0.95rem;
}

.diff-buttons {
    display: flex;
    gap: 6px;
    width: 100%;
    justify-content: space-between;
}

.diff-btn {
    flex: 1;
    padding: 8px 4px;
    background: #bdc3c7;
    color: #2c3e50;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: bold;
    transition: all 0.2s ease;
}

.diff-btn:hover {
    background: #95a5a6;
    color: white;
}

.diff-btn.active {
    background: #3498db;
    color: white;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.15);
}


/* Estilos el tablero */
#board-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 25px;
    width: 100%;
}

#game-board {
    display: grid;
    grid-template-columns: repeat(4, 80px);
    grid-template-rows: repeat(4, 80px);
    gap: 5px;
    background: #bdc3c7;
    padding: 10px;
    border-radius: 5px;
}

.cell {
    background: #ecf0f1;
    width: 80px;
    height: 80px;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 3px;
    cursor: pointer;
    position: relative;
}

/* Controles de estado y reinicio */
#game-controls {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    width: 100%;
}

#status {
    padding: 10px;
    text-align: center;
    font-weight: bold;
    width: 100%;
    max-width: 335px;
}

#btn-restart {
    width: 100%;
    max-width: 335px;
    background: #e74c3c;
}

#btn-restart:hover {
    background: #c0392b;
}

/* Fichas */
.piece {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    transition: transform 0.2s, box-shadow 0.2s;
}

.player1 {
    background: #e74c3c;
    box-shadow: inset -5px -5px 10px rgba(0,0,0,0.2);
}

.player2 {
    background: #2980b9;
    box-shadow: inset -5px -5px 10px rgba(0,0,0,0.2);
}

.piece.selected {
    transform: scale(1.1);
    box-shadow: 0 0 15px rgba(241, 196, 15, 0.8);
    border: 3px solid #f1c40f;
}

.invalid-move {
    background-color: #e74c3c !important; /* Rojo */
    transition: background-color 0.2s ease-in-out;
}

/* Sección de Reglas */
#rules-section {
    max-width: 500px;
}

#rules-section h2, #rules-section h3 {
    margin-bottom: 10px;
    color: #2c3e50;
}

#rules-section p, #rules-section ul {
    margin-bottom: 15px;
    line-height: 1.6;
}

#rules-section ul {
    padding-left: 20px;
}

hr {
    border: 0;
    height: 1px;
    background: #ccc;
    margin: 15px 0;
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: flex-end;
    padding-bottom: 40px;
    z-index: 1000;
}

.modal-content {
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 -5px 25px rgba(0,0,0,0.2);
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 20px;
    width: 600px;
    max-width: 90%;
    animation: slideUp 0.3s ease-out;
}

#modal-btn-restart {
    padding: 15px 30px;
    background: #e74c3c;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.3s;
}

#modal-btn-restart:hover {
    background: #c0392b;
}

@keyframes slideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}