* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Arial', sans-serif;
}

body {
    background-color: #f5f5f5;
    color: #333;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
    text-align: center;
}

header {
    margin-bottom: 20px;
}

h1 {
    color: #3f51b5;
    margin-bottom: 15px;
}

.score-container {
    display: flex;
    justify-content: space-around;
    margin: 15px 0;
    font-size: 1.2em;
    font-weight: bold;
}

.instructions {
    font-size: 1.5em;
    background-color: #fff;
    padding: 10px;
    border-radius: 10px;
    margin: 15px auto;
    width: fit-content;
    min-width: 300px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.home-button {
    display: inline-block;
    margin: 10px;
    padding: 8px 16px;
    background-color: #3f51b5;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: background-color 0.3s;
}

.home-button:hover {
    background-color: #303f9f;
}

#game-container {
    position: relative;
    width: 100%;
    height: 500px;
    background-color: #e8eaf6;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 6px 12px rgba(0,0,0,0.1);
}

#start-screen, #game-over {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: rgba(255, 255, 255, 0.9);
    z-index: 10;
}

#game-area {
    width: 100%;
    height: 100%;
    padding: 20px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

#numbers-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 15px;
    margin-bottom: 30px;
    min-height: 200px;
    width: 100%;
}

.number-card {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #5c6bc0, #3f51b5);
    color: white;
    font-size: 2em;
    font-weight: bold;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
    cursor: move;
    user-select: none;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
    transition: transform 0.2s;
}

.number-card:hover {
    transform: scale(1.05);
}

.number-card.dragging {
    opacity: 0.5;
    transform: scale(1.1);
}

.success-animation {
    animation: success 0.5s ease-in-out;
}

@keyframes success {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); background: linear-gradient(135deg, #66bb6a, #43a047); }
    100% { transform: scale(1); }
}

.error-animation {
    animation: error 0.5s ease-in-out;
}

@keyframes error {
    0% { transform: scale(1); }
    25% { transform: scale(1.05); background: linear-gradient(135deg, #ef5350, #e53935); }
    50% { transform: scale(0.95); background: linear-gradient(135deg, #ef5350, #e53935); }
    75% { transform: scale(1.05); background: linear-gradient(135deg, #ef5350, #e53935); }
    100% { transform: scale(1); }
}

button {
    padding: 12px 25px;
    margin: 15px 0;
    background-color: #3f51b5;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 1.1em;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #303f9f;
}

#check-button {
    background-color: #4caf50;
}

#check-button:hover {
    background-color: #388e3c;
}

.hidden {
    display: none !important;
}

/* For drag and drop functionality */
.drop-target {
    border: 2px dashed #3f51b5;
    background-color: rgba(63, 81, 181, 0.1);
}