/* Globální styly a styly pro hlavičku a patičku */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: #fafafa;
    color: #333;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: #fff;
    padding: 10px 20px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    justify-content: space-between;
    z-index: 1000;
}

header img {
    height: 50px;
}

main {
    padding: 100px 20px 40px;
    width: 75%;
    max-width: 960px;
    margin: 0 auto;
    flex-grow: 1;
}

main h2 {
    margin-bottom: 20px;
    text-align: center;
    font-weight: 600;
    font-size: 1.8rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
}

.card {
    background: #7d0043;
    padding: 20px;
    text-align: center;
    cursor: pointer;
    border-radius: 0;
    color: white;
}

.card-sh {
    background: #0069b4;
    padding: 20px;
    text-align: center;
    cursor: pointer;
    border-radius: 0;
    color: white;
}


footer {
    text-align: center;
    padding: 20px;
    color: #777;
    font-size: 0.9rem;
    background-color: #f1f3f5;
    margin-top: auto;
    display: flex;
    justify-content: center;
    align-items: center;
    padding-bottom: 30px;
}

footer a {
    color: #777;
}

.copyright {
    margin: 0 auto;
}

/* Styly pro sekci procvičování */
#practice-section {
background: #fff;
padding: 30px;
box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
margin-top: 30px;
max-width: 500px;
margin-left: auto;
margin-right: auto;
text-align: center;
}

.problem p {
    font-size: 2rem;
    margin-bottom: 20px;
}

#user-answer {
width: 100%;
padding: 10px;
margin-bottom: 15px;
border: 1px solid #ced4da;
text-align: center;
font-size: 1.5rem;
}

#check-btn,
#next-problem-btn {
display: block;
width: 100%;
padding: 12px;
border: none;
cursor: pointer;
font-size: 1rem;
font-weight: bold;
}

#check-btn {
background-color: #7d0043;
color: white;
}

#next-problem-btn {
background-color: #28a745;
color: white;
margin-top: 10px;
}

#result-message {
font-weight: bold;
margin-top: 15px;
}

@media (max-width: 768px) {
    main {
        width: 90%;
    }
}

main hr {
    border: none;
    border-top: 1px solid #ccc;
    margin: 40px 0;
}