:root {
    --bg-gradient-start: #3498db;
    --bg-gradient-end: #8e44ad;
    --container-bg: rgba(255, 255, 255, 0.1);
    --text-color: #fff;
    --border-color: rgba(255, 255, 255, 0.2);
    --button-bg: #e74c3c;
    --button-hover-bg: #c0392b;
}

body.dark-mode {
    --bg-gradient-start: #2c3e50;
    --bg-gradient-end: #34495e;
    --container-bg: rgba(0, 0, 0, 0.2);
    --text-color: #ecf0f1;
    --border-color: rgba(255, 255, 255, 0.1);
    --button-bg: #e74c3c;
    --button-hover-bg: #c0392b;
}


body {
    margin: 0;
    font-family: 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(45deg, var(--bg-gradient-start), var(--bg-gradient-end));
    transition: background 0.5s ease;
}

.container {
    text-align: center;
    background: var(--container-bg);
    padding: 40px;
    border-radius: 15px;
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    transition: background 0.5s ease;
}

h1 {
    color: var(--text-color);
    margin-bottom: 30px;
}

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

.number-circle {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    color: #fff;
    opacity: 0;
    transform: scale(0.5);
    animation: appear 0.5s forwards;
}

#generate-btn {
    background-color: var(--button-bg);
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 18px;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
}

#generate-btn:hover {
    background-color: var(--button-hover-bg);
    transform: scale(1.05);
}

@keyframes appear {
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Theme Switch */
.theme-switch-wrapper {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    margin-bottom: 20px;
}

.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: #2196F3;
}

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

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

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