/* Variables para temas */
:root {
    --bg-color: #f4f4f4;
    --calculator-bg: #ffffff;
    --display-bg: #f8f8f8;
    --btn-bg: #e0e0e0;
    --btn-color: #333333;
    --btn-hover: #d4d4d4;
    --operator-bg: #4CAF50;
    --operator-color: #ffffff;
    --operator-hover: #45a049;
    --function-bg: #ff9800;
    --function-color: #ffffff;
    --function-hover: #f57c00;
    --display-text: #333333;
    --history-text: #666666;
    --shadow: rgba(0, 0, 0, 0.1);
}

/* Tema oscuro */
.dark-mode {
    --bg-color: #1a1a1a;
    --calculator-bg: #2d2d2d;
    --display-bg: #363636;
    --btn-bg: #424242;
    --btn-color: #ffffff;
    --btn-hover: #4f4f4f;
    --operator-bg: #2e7d32;
    --operator-color: #ffffff;
    --operator-hover: #1b5e20;
    --function-bg: #e65100;
    --function-color: #ffffff;
    --function-hover: #bf360c;
    --display-text: #ffffff;
    --history-text: #b3b3b3;
    --shadow: rgba(0, 0, 0, 0.3);
}

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

body {
    background-color: var(--bg-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s ease;
}

.calculator-container {
    width: 100%;
    max-width: 400px;
    padding: 20px;
}

.calculator {
    background-color: var(--calculator-bg);
    border-radius: 20px;
    padding: 20px;
    box-shadow: 0 8px 24px var(--shadow);
    transition: all 0.3s ease;
}

.theme-toggle {
    text-align: right;
    margin-bottom: 10px;
}

#themeToggle {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    transition: transform 0.3s ease;
}

#themeToggle:hover {
    transform: scale(1.1);
}

.display-container {
    background-color: var(--display-bg);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    text-align: right;
}

.history {
    height: 100px;
    color: var(--history-text);
    font-size: 0.9rem;
    margin-bottom: 5px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 5px;
}

.display {
    color: var(--display-text);
    font-size: 2.5rem;
    font-weight: bold;
    overflow-x: auto;
    white-space: nowrap;
}

.keypad {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
}

.btn {
    border: none;
    padding: 15px;
    font-size: 1.1rem;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    background-color: var(--btn-bg);
    color: var(--btn-color);
}

.btn:hover {
    transform: scale(0.95);
    background-color: var(--btn-hover);
}

.operator {
    background-color: var(--operator-bg);
    color: var(--operator-color);
}

.operator:hover {
    background-color: var(--operator-hover);
}

.function {
    background-color: var(--function-bg);
    color: var(--function-color);
}

.function:hover {
    background-color: var(--function-hover);
}

.equals {
    background-color: var(--operator-bg);
    color: var(--operator-color);
}

.equals:hover {
    background-color: var(--operator-hover);
}

/* Responsive design */
@media (max-width: 480px) {
    .calculator-container {
        padding: 10px;
    }

    .calculator {
        padding: 15px;
    }

    .btn {
        padding: 12px;
        font-size: 1rem;
    }

    .display {
        font-size: 2rem;
    }
}

/* Estilos para la barra de desplazamiento */
.history::-webkit-scrollbar {
    width: 8px;
}

.history::-webkit-scrollbar-track {
    background-color: var(--display-bg);
    border-radius: 10px;
}

.history::-webkit-scrollbar-thumb {
    background-color: var(--function-bg);
    border-radius: 10px;
    border: 2px solid var(--display-bg);
    transition: background-color 0.3s ease;
}

.history::-webkit-scrollbar-thumb:hover {
    background-color: var(--function-hover);
}

/* Animaciones */
@keyframes buttonPress {
    0% { transform: scale(1); }
    50% { transform: scale(0.95); }
    100% { transform: scale(1); }
}

.btn:active {
    animation: buttonPress 0.2s ease;
}