:root {
    --background-color: #f0f2f5;
    --container-background: #ffffff;
    --text-color: #333;
    --h1-color: #333;
    --number-color: #fff;
    --button-text-color: #fff;
    --background-image-opacity: 0.1;
}

[data-theme="dark"] {
    --background-color: #121212;
    --container-background: #1e1e1e;
    --text-color: #e0e0e0;
    --h1-color: #e0e0e0;
    --background-image-opacity: 0.05;
}

@keyframes fadeInSlideUp {
    0% {
        opacity: 0;
        transform: translateY(20px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes textFocusIn {
    0% {
        filter: blur(12px);
        opacity: 0;
    }
    100% {
        filter: blur(0px);
        opacity: 1;
    }
}

@keyframes popAndRotate {
    0% {
        transform: scale(0) rotateY(360deg);
    }
    70% {
        transform: scale(1.2) rotateY(0deg);
    }
    100% {
        transform: scale(1) rotateY(0deg);
    }
}


body {
    font-family: 'Helvetica Neue', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: var(--background-color);
    background-image: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%239C92AC' fill-opacity='var(--background-image-opacity)'%3E%3Cpath d='M0 38.59l2.83-2.83 1.41 1.41L1.41 40H0v-1.41zM0 1.4l2.83 2.83 1.41-1.41L1.41 0H0v1.41zM38.59 40l-2.83-2.83 1.41-1.41L40 38.59V40h-1.41zM40 1.41l-2.83 2.83-1.41-1.41L38.59 0H40v1.41zM20 18.6l2.83-2.83 1.41 1.41L21.41 20l2.83 2.83-1.41 1.41L20 21.41l-2.83 2.83-1.41-1.41L18.59 20l-2.83-2.83 1.41-1.41L20 18.59z'/%3E%3C/g%3E%3C/svg%3E");
    color: var(--text-color);
    perspective: 1000px;
}

.container {
    text-align: center;
    padding: 40px;
    border-radius: 20px;
    background-color: var(--container-background);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1), 0 6px 6px rgba(0, 0, 0, 0.1);
    position: relative;
    animation: fadeInSlideUp 0.8s ease-out forwards;
}

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

.theme-switch {
    display: inline-block;
    height: 34px;
    position: relative;
    width: 60px;
}

.theme-switch input {
    display: none;
}

.slider {
    background-color: #ccc;
    bottom: 0;
    cursor: pointer;
    left: 0;
    position: absolute;
    right: 0;
    top: 0;
    transition: .4s;
}

.slider:before {
    background-color: #fff;
    bottom: 4px;
    content: "";
    height: 26px;
    left: 4px;
    position: absolute;
    transition: .4s;
    width: 26px;
}

input:checked + .slider {
    background-color: #2575fc;
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}


h1 {
    font-size: 3rem;
    color: var(--h1-color);
    margin-bottom: 30px;
    letter-spacing: -1px;
    animation: textFocusIn 1s ease-in-out;
}

.numbers-container {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
}

.number {
    width: 60px;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.8rem;
    font-weight: bold;
    color: var(--number-color);
    border-radius: 50%;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2), 0 2px 5px rgba(0,0,0,0.15);
    animation-duration: 0.8s;
    animation-timing-function: cubic-bezier(0.34, 1.56, 0.64, 1);
    animation-fill-mode: forwards;
}

.number.pop {
    animation-name: popAndRotate;
}


#generate-btn {
    padding: 15px 30px;
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--button-text-color);
    background: linear-gradient(45deg, #6a11cb, #2575fc);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

#generate-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(37, 117, 252, 0.4), 0 4px 10px rgba(106, 17, 203, 0.3);
}

#generate-btn:active {
    transform: translateY(-1px);
    box-shadow: 0 2px 10px rgba(37, 117, 252, 0.3), 0 2px 5px rgba(106, 17, 203, 0.2);
}