:root {
    --bg-gradient-start: #d16ba5;
    --bg-gradient-end: #5ffbf1;
    --container-bg: rgba(255, 255, 255, 0.8);
    --text-color: #333;
    --h1-color: #2c3e50;
    --btn-bg: #3498db;
    --btn-hover-bg: #2980b9;
    --btn-shadow: rgba(52, 152, 219, 0.4);
    --btn-hover-shadow: rgba(41, 128, 185, 0.5);
}

body.dark-mode {
    --bg-gradient-start: #2c3e50;
    --bg-gradient-end: #34495e;
    --container-bg: rgba(44, 62, 80, 0.8);
    --text-color: #ecf0f1;
    --h1-color: #ecf0f1;
    --btn-bg: #1abc9c;
    --btn-hover-bg: #16a085;
    --btn-shadow: rgba(26, 188, 156, 0.4);
    --btn-hover-shadow: rgba(22, 160, 133, 0.5);
}


body {
    font-family: 'Arial', sans-serif;
    background-color: #f0f2f5;
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-image: linear-gradient(to right top, var(--bg-gradient-start), #c777b9, #ba83ca, #aa8fd8, #9a9ae1, #8aa7ec, #79b3f4, #69bff8, #52cffe, #41dfff, #46eefa, var(--bg-gradient-end));
    transition: background-color 0.3s ease, color 0.3s ease;
}

.theme-switcher-container {
    position: absolute;
    top: 1rem;
    right: 1rem;
}

#theme-toggle-btn {
    padding: 0.5rem 1rem;
    font-size: 1rem;
    color: white;
    background-color: var(--btn-bg);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.container {
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    text-align: center;
    backdrop-filter: blur(10px);
}

h1 {
    margin-bottom: 2rem;
    font-size: 2.5rem;
    color: var(--h1-color);
}

.number-display {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.number-circle {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: bold;
    color: white;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

#generate-btn {
    padding: 1rem 2rem;
    font-size: 1.2rem;
    color: white;
    background-color: var(--btn-bg);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--btn-shadow);
}

#generate-btn:hover {
    background-color: var(--btn-hover-bg);
    box-shadow: 0 6px 20px var(--btn-hover-shadow);
    transform: translateY(-2px);
}