body {
    font-family: sans-serif;
    line-height: 1.6;
    margin: 20px;
    background-color: #f4f4f4;
    color: #333;
}

h1, h2 {
    text-align: center;
}

#add-word-container, #flashcard-container {
    max-width: 500px;
    margin: 20px auto;
    padding: 20px;
    background: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

#add-word-form {
    display: flex;
    flex-direction: column;
}

#add-word-form input, #add-word-form button {
    margin-bottom: 10px;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 3px;
}

#add-word-form button {
    background: #333;
    color: #fff;
    cursor: pointer;
}

#flashcards {
    perspective: 1000px;
    height: 200px;
    margin-bottom: 20px;
}

.flashcard {
    width: 100%;
    height: 100%;
    position: absolute;
    transform-style: preserve-3d;
    transition: transform 0.6s;
    cursor: pointer;
}

.flashcard.is-flipped {
    transform: rotateY(180deg);
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5em;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.card-face-front {
    background: #fff;
}

.card-face-back {
    background: #f0f0f0;
    transform: rotateY(180deg);
}

#prev-btn, #next-btn {
    padding: 10px 20px;
    border: none;
    background: #333;
    color: #fff;
    border-radius: 3px;
    cursor: pointer;
}