@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300&display=swap');

:root {
    --header-height: 64px;
    --footer-height: 48px;
    --main-font-color: #000000;
    --header-font-color: #ffffff;
    --footer-font-color: #ffffff;
    --header-bg-color: #000000;
    --footer-bg-color: #999999;
    --top-img-ratio: calc(683 / 1024);
}

html {
    font-size: 12px;
}
@media screen and (min-width: 481px) {
    html {
        font-size: 16px;
    }
}

html, body, header, main, footer, div, img, h1, ul, li, p {
    margin: 0;
    padding: 0;
    border-width: 0;
    font-family: 'Noto Sans JP', sans-serif;
}

html, body, header, main, footer {
    box-sizing: border-box;
}

body {
    overflow: hidden;
    line-height: 1.5rem;
}

header {
    display: flex;
    position: fixed;
    top: 0;
    width: 100vw;
    height: var(--header-height);
    z-index: 100;
    background-color: var(--header-bg-color);
}

header h1 {
    order: 1;
    flex-grow: 1;
    margin-left: 1rem;
    margin-right: 1rem;
    line-height: var(--header-height);
    font-size: 2rem;
    font-weight: bold;
    color: var(--header-font-color);
    float: left;
}

header h1 a, header h1 a:hover {
    color: var(--header-font-color);
    text-decoration: none;
}

header h1 img {
    vertical-align: middle;
}

header .menu-button {
    order: 2;
    flex-basis: var(--header-height);
    line-height: var(--header-height);
    text-align: center;
    font-size: 2rem;
    color: var(--header-font-color);
}

footer {
    width: 100vw;
    height: var(--footer-height);
    padding: 5px;
    padding-right: 24px;
    background-color: var(--footer-bg-color);
    color: var(--footer-font-color);
    text-align: right;
    overflow-y: auto;
}

footer .copyright {
    font-size: 0.9rem;
}

nav {
    position: fixed;
    width: 100vw;
    top: 0;
    left: 0;
    z-index: 1010;
    text-align: center;
    color: var(--header-font-color);
    background-color: transparent;
    transform: translateY(-100%);
    transition-property: transform;
    transition-duration: 500ms;
    transition-timing-function: ease;
}

nav.active {
    transform: translateY(0);
}

nav h1 {margin-top: -2.5rem;
    text-align: center;
    font-size: 1.5rem;
    font-weight: bold;
}

nav ul {
    list-style: none;
    padding: 1.2rem;
}

nav ul li {
    margin-bottom: 1.2rem;
}

nav a { 
    color: var(--header-font-color);
    font-weight: normal;
}

nav .close-button {
    width: var(--header-height);
    height: var(--header-height);
    line-height: var(--header-height);
    margin-left: auto;
    margin-right: 0;
    background-color: #000000;
    text-align: center;
    font-size: 2rem;
    color: var(--header-font-color);
}

#curtain {
    position: fixed;
    width: 100vw;
    height: 100vh;
    top: 0;
    left: 0;
    z-index: 1000;
    background-color: #666666;
    visibility: hidden;
    opacity: 0;
    transition-property: visibility, opacity;
    transition-duration: 300ms;
    transition-timing-function: ease;
}

#curtain.active {
    visibility: visible;
    opacity: 0.9;
}

main {
    position: relative;
    width: 100vw;
    margin-top: var(--header-height);
    height: calc(100vh - var(--header-height));
    overflow-y: scroll;
    overflow-x: hidden;
}

article {
    padding: 1rem;
    min-height: calc(100vh - var(--header-height) - var(--footer-height));
}
@media screen and (min-width: 1024px) {
    article {
        padding: 1rem calc(1rem + (100vw - 1024px) / 2);
    }
}

article h1 {
    margin-bottom: 2rem;
    font-size: 2rem;
    font-weight: bold;
}

section {
    width: 100%;
    text-align: left;
}

section h1 {
    margin-top: 2rem;
    margin-bottom: 2rem;
    font-size: 1.6rem;
    font-weight: bold;
}

section h2 {
    margin-top: 1.5rem;
    margin-bottom: 1.5rem;
    font-size: 1.2rem;
    text-decoration-line: underline;
}

section p {
    margin: 1rem;
    font-size: 1rem;
}


ul.sns {
    display: inline-block;
    height: 1.5rem;
    color: var(--footer-font-color);
    list-style: none;
}

ul.sns > li {
    float: left;
    margin-left: 0.6rem;
    line-height: 2.2rem;
    font-size: 1.2rem;
}

ul.sns::after {
    content: "";
    clear: both;
}

ul.sns > li > a {
    color: var(--footer-font-color);
}

a {
    color: var(--main-font-color);
    font-weight: bold;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}