* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, Helvetica, sans-serif;
}

.container {
    display: flex;
    height: 100vh;
    flex-wrap: wrap; /* allows wrapping for small screens */
}

/* Left half */
#lightMode {
    background-color: #f4f4f2;
    width: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

/* Right half */
#darkMode {
    background-color: #42404b;
    width: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.box1, .box2 {
    height: auto;
    width: 90%;
    max-width: 500px;
    padding: 30px 20px;
    text-align: center;
    border-radius: 30px;
    transition: all 0.5s ease;
}

span {
    font-size: 6em;
}

h2 {
    font-size: 1.8em;
    margin-top: 20px0;
}

p {
    font-size: 1em;
    margin: 15px 10px;
    text-align: center;
}

button {
    margin-top: 20px;
}

.btn {
    border: none;
    border-radius: 50px;    
    font-size: 1.1em;
    font-weight: 900;
    padding: 12px 35px;
    background-color: #e5e5e5;
    color: #333;
    cursor: pointer;
    transition: transform 0.3s;
}

.btn:active {
    transform: scale(1.1);
}

/* Modes */
.light-mode {
    background-color: #ffffff;
    color: #000000;
}

.dark-mode {
    background-color: #26242f;
    color: #ffffff;
}

/* Labels */
.light, .dark {
    font-size: 6em;
    margin-top: 20px;
}

@media (max-width: 992px) {
    .container {
        flex-direction: column; /* stack on tablets & mobiles */
        height: auto;
    }

    #lightMode, #darkMode {
        width: 100%;
        min-height: 50vh; /* each takes full screen height */
    }

    .light, .dark {
        font-size: 4em;
    }

    span {
        font-size: 4em;
    }
}

@media (max-width: 600px) {
    .box1, .box2 {
        width: 95%;
        padding: 20px 15px;
    }

    h2 {
        font-size: 1.5em;
    }

    p {
        font-size: 0.9em;
    }

    .btn {
        font-size: 1em;
        padding: 10px 25px;
    }

    .light, .dark {
        font-size: 3em;
    }

    span {
        font-size: 3.5em;
    }
}