:root {
    --bg-color: #f0f0f0;
    --container-bg: #ffffff;
    --text-color: #333333;
    --number-bg: #eeeeee;
    --number-text: #000000;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --btn-bg: #4CAF50;
    --btn-text: #ffffff;
    --transition-speed: 0.3s;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --number-bg: #444444;
    --number-text: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.3);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 2.5rem;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--shadow-color);
    transition: background-color var(--transition-speed), box-shadow var(--transition-speed);
    position: relative;
    max-width: 400px;
    width: 90%;
}

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

#theme-btn {
    background: none;
    border: 2px solid var(--text-color);
    color: var(--text-color);
    padding: 0.5rem;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-speed);
}

#theme-btn:hover {
    background-color: var(--text-color);
    color: var(--container-bg);
}

h1 {
    margin-bottom: 2rem;
    font-size: 1.8rem;
}

.lotto-numbers {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-bottom: 2rem;
}

.number {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background-color: var(--number-bg);
    color: var(--number-text);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.1rem;
    font-weight: bold;
    box-shadow: 0 4px 6px var(--shadow-color);
    transition: transform 0.2s, background-color var(--transition-speed);
}

.number:not(:empty) {
    transform: scale(1.1);
}

#generate-btn {
    padding: 1rem 2rem;
    font-size: 1.1rem;
    background-color: var(--btn-bg);
    color: var(--btn-text);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
    transition: transform 0.1s, opacity 0.2s;
    box-shadow: 0 4px 10px rgba(76, 175, 80, 0.3);
}

#generate-btn:active {
    transform: scale(0.95);
}

#generate-btn:hover {
    opacity: 0.9;
}