.header-container {
    text-align: center;
    background: linear-gradient(to right, #5d5c49, #d3d5b0);
}

a i {
    font-size: 1.50rem;
    margin-right: 1rem;
    color: #5d5c49;
}

main {
    position: relative;
    display: flex;
    flex-direction: column;
    background-color: aqua;
    height: 100%;
    width: 100%;
}

#problem {
    position: relative;
    display: inline-flex;
    flex-shrink: 0;
    height: 80vh;
    width: 100%;
    justify-content: flex-start;
    align-items: center;
    padding: 0 0 0 80px;
    background-color: aliceblue;
}

.logo {
    filter: grayscale(100%);
}

#problem article {
    position: relative;
    display: flex;
    justify-content: center;
    font-size: 1.75rem;
}

#subject-problem {
    position: absolute;
    display: flex;
    flex-direction: column;
    right: 120px;
    background-image: url('../imgs/problem.jpeg');
    width: 50%;
    height: 300px;
    filter: grayscale(100%);
    background-size: cover;
    justify-content: center;
    align-items: flex-start;
    padding: 0 0 0 50px;
    background-position: center;
    background-repeat: no-repeat;
    transition: transform 0.5s;
}

#title {
    display: flex;
    flex-direction: column;
}

#title h2 {
    font-size: 1.3rem;
    text-align: end;
}

#subject-problem:hover {
    transform: scale(1.10);
}

#subject-problem:hover > .link-access {
    opacity: 1;
}

#subject-problem img {
    height: 200px;
    width: auto;
    filter: grayscale(100%);
}

.problem-subject {
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 10px;
    isolation: isolate;
}

.link-access {
    opacity: 0;
    transition: opacity 0.5s;
}

.link-access > p a {
    color: white;
    font-size: 1rem;
    font-weight: 600;
}

.problem-subject h1 {
    display: inline-block;
    color: white;
    filter: grayscale(0); 
    background-color: aqua;
    position: relative;
}

.problem-subject h1:nth-child(2) {
    width: 67%;
}

#more-subjects {
    position: relative;
    display: flex;
    flex-direction: column;
    height: 70vh;
    width: 100%;
    flex-shrink: 0;
    justify-content: center;
    align-items: center;
    background-color: whitesmoke;
    gap: 50px;
}

#more-subjects-title {
    position: relative;
}

#more-subjects-title h1 {
    font-size: 2rem;
}

#more-subjects-title > h1::before {
    content: '';
    position: absolute;
    height: 2px;
    width: 100%;
    background-color: black;
    bottom: 0;
}

#subjects {
    position: relative;
    display: inline-flex;
    gap: 25px;
}

.subject-content {
    position: relative;
    display: flex;
    height: 30vh;
    width: 20vw;
    background-size: cover;
    justify-content: center;
    align-items: center;
    padding: 0 0 0 20px;
    background-position: center;
    background-repeat: no-repeat;
    filter: grayscale(100%);
    transition: all 0.5s;
}

.subject-content h2 {
    font-size: 1.2rem;
    color: white;
    opacity: 0;
    text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.5);
    transition: opacity 0.5s;
}

.subject-content:hover > h2 {
    opacity: 1;
}

.subject-content:hover {
    transform: scale(1.1);
    border-radius: 10px;
}

#one-subject {
    background-image: url('../img/one-subject.avif');
}

#two-subject {
    background-image: url('../img/two-subject.png')
}

#three-subject {
    background-image: url('../img/three-subject.jpg');
}

#problem-description {
    position: relative;
    display: flex;
    flex-shrink: 0;
    height: 100vh;
    width: 100%;
    justify-content: center;
    align-items: center;
    background-color: azure;
}

#problem-description article {
    display: flex;
    flex-direction: column;
    font-size: 1.5rem;
    line-height: 35px;
    gap: 10px;
    text-align: center;
}

footer {
    display: flex;
    flex-flow: column wrap;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: #3d3d34;
    font-weight: 500;
    padding: 2rem;
    border-top: 1px solid #3d3d34;
    background: linear-gradient(to right, #5d5c49, #d3d5b0);
}