*,*::before,*::after{
box-sizing: border-box;
}

body {
    margin: 0;
    font-family: 'Arial', sans-serif;
    background-color: #121212;
    color: #fff;
}

header {
    background-color: #1a1a1a;
    padding: 1.25rem 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    color: #e63946;
    margin: 0;
    font-size: 2rem;
}

.navbar-nav {
    list-style: none;
    display: flex;
    gap: 1.56rem;
    margin: 0;
    padding: 0;
}

.nav-link {
    color: #fff;
    text-decoration: none;
    font-weight: 600;
}

footer {
    background-color: #1a1a1a;
    padding: 2.5rem 1.25rem;
    color: #fff;
    font-weight: 600;

    display: flex;
    justify-content: space-between;
    align-items: center;
}

main {
    flex: 1;
    margin: 0;
    max-width: none;
    padding: 2.5rem 1.25rem;
}

.card-exercise {
    width: 18.75rem;
    border-radius: 0.75rem;
    overflow: hidden;
    background: #000;
}

.media {
    position: relative;
    width: 100%;
    height: 16.625rem;
}

.card-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.card-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.card-exercise:hover .card-video {
    opacity: 1;
}

.card-exercise:hover .card-img {
    opacity: 0;
}

.card-content {
    background: #e63946;
    color: #000;
    text-align: center;
    padding: 1rem;
    font-weight: 600;
}

.back-container,
.bicep-container {
    display: flex;
    flex-wrap: wrap;
    gap: 1.25rem;
    justify-content: center;
}

.titels {
    text-align: left;
    margin: 2.5rem 0 1.25rem 0;
    font-size: 1.3rem;
    color: #e63946;
    font-weight: 600;
}

.layout {
    display: flex;
    flex-direction: row-reverse;
    gap: 2.5rem;
    padding: 2.5rem;
    align-items: flex-start;
}

#container {
    flex: 0 0 37rem;
    position: sticky;
    top: 1.25rem;
}

#container svg {
    width: 100%;
    height: auto;
}

.cards-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: 1.25rem;
    justify-content: flex-start;
}