.category {
    padding-top: 10px;
    height: 5vmin;
	/* Center slide text vertically */
	display: -webkit-box;
	display: -ms-flexbox;
	display: -webkit-flex;
	display: flex;
	-webkit-box-pack: space-around;
	-ms-flex-pack: space-around;
	-webkit-justify-content: space-around;
	justify-content: space-around;
	-webkit-box-align: center;
	-ms-flex-align: center;
	-webkit-align-items: center;
    align-items: center;
}

.category label {
    width: calc(100% / 3);
    height: 100%;
    font-size: 2.5vmin;
    text-align: center;
}

.category input[type="radio"] {
    /* hiding radio button */
    display: none;
}

.category input[type="radio"] ~ span {
    /* make as block element (enabling to set size) */
    display: inline-block;
    /* shape and size */
    border: thin solid gray;
    border-radius: 5px 5px 0 0;
    /* size is same as the parent */
    width: 100%;
    height: 100%;
    /* text centering */
    line-height: 5vmin;
    vertical-align: middle;
    /* mouse cursor */
    cursor: pointer;
}

.category input[type="radio"]:checked ~ span {
    font-weight: bold;
}
.category input[type="radio"][value="company"]:checked ~ span {
    background: linear-gradient(to top, var(--reve-color-violet), transparent);
    border-bottom: thin solid var(--reve-color-violet);
}
.category input[type="radio"][value="history"]:checked ~ span {
    background: linear-gradient(to top, var(--reve-color-blue), transparent);
    border-bottom: thin solid var(--reve-color-blue);
}
.category input[type="radio"][value="member"]:checked ~ span {
    background: linear-gradient(to top, var(--reve-color-purple), transparent);
    border-bottom: thin solid var(--reve-color-purple);
}

main {
    position: relative;
    /* no horizontal scroll bar (need to set position and height) */
    overflow-x: hidden;
}

article {
    position: absolute;
    height: calc(100% - 5vmin - 10px);
    overflow-y: auto;
    /* make clearance on both sides */
    width: 60%;
    padding: 0 calc((100% - 60%) / 2);
    /* font */
    font-family: Cambria, Cochin, Georgia, Times, 'Times New Roman', serif;
    font-size: 2rem;
	/* animation */
	transition: opacity .5s, visibility .5s, transform .5s;
	/* fade out */
	opacity: 0;
    visibility: hidden;
    transform: translateX(100%);
}
article.visible {
	/* fade in */
	opacity: 1;
    visibility: visible;
    transform: translateX(0%);
}

article section {
    margin: 15px auto;
    list-style-position: inside;
}

article#company .profile .title {
    margin-right: 0;
}

article#company .profile .title h1 {
    font-size: 8vmin;
}

article#company .profile .phonics {
    font-size: 3vmin;
}

article#company .profile img {
    max-width: 20%;
    margin: auto;
    margin-left: 0;
}

article#history {
    display: inline-flex;
    /* make clearance on both sides */
    width: 90%;
    padding: 0 calc((100% - 90%) / 2);
}

article#history > section {
    width: 30%;
    /* max-width: calc(100% / 3); */
    /* padding: 0 5%; */
}

article#history section h1 {
    font-size: 3.2rem;
    color: gray;
    font-style: italic;
}

article#history section h2 {
    font-size: 2.4rem;
}

article#history section.title {
    border-bottom: ridge thin lightgray;
}

article#history section.title .description > * {
    font-size: 1.6rem;
    word-break: break-all;
}

article#member .person {
    margin-bottom: 50px;
}

article#member .person h1 {
    font-size: 2.4em;
    text-align: center;
}
article#member .person h2 {
    font-size: 1.6em;
}
article#member .person li {
    font-size: 0.8em;
}

/* adjusting to small screen size */
@media screen and (max-width: 480px) {
    article{
        /* make clearance on both sides */
        width: 90%;
        padding: 0 calc((100% - 90%) / 2);
    }
    
    article#company .profile .title h1 {
        font-size: 10vmin;
    }

    article#history {
        display: inline-block;
        flex-direction: column;
    }
    article#history section {
        /* max-width: 100%; */
        width: 100%;
    }
}