:root {
    --bg: #fff;
    --text: #000;
    --btn: #000;
    --btn-text: #fff;
    --card: #f9f9f9;
    --border: #ccc;
}

body {
    margin:0;
    font-family: Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
}

.container {
    max-width: 900px;
    margin: auto;
    padding: 20px;
    text-align: center;
}

h1 {
    margin-bottom: 30px;
}

.buttons a.btn {
    display: inline-block;
    background: var(--btn);
    color: var(--btn-text);
    text-decoration: none;
    padding: 12px 25px;
    margin: 10px;
    border-radius: 8px;
    font-weight: bold;
    transition: 0.3s;
}

.buttons a.btn:hover {
    opacity: 0.8;
}

/* Flashcards CSS */
.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 20px;
    padding: 20px 0;
}

.card {
    perspective: 1000px;
    width: 100%;
    padding-top: 60%;
    position: relative;
}

.card-inner {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: transform 0.6s;
    border-radius: 16px;
}

.card.flipped .card-inner {
    transform: rotateY(180deg);
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 16px;
    border: 1px solid var(--border);
    background: var(--card);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 10px;
    backface-visibility: hidden;
    font-size: 0.9rem;
    text-align: center;
    box-sizing: border-box;
}

.card-back {
    transform: rotateY(180deg);
}

/* Formok */
.form-box {
    max-width: 400px;
    margin: auto;
    background: var(--card);
    padding: 25px;
    border-radius: 12px;
    text-align: left;
}

.form-box input {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.form-box button {
    width: 100%;
    padding: 12px;
    margin-top: 10px;
    border: none;
    background: var(--btn);
    color: var(--btn-text);
    font-weight: bold;
    border-radius: 8px;
    cursor: pointer;
}