html {
  box-sizing: border-box;
}

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

body {
  font-family: 'Yu Gothic', 'Meiryo', 'Noto Sans JP', sans-serif;
  color: #000;
  background-color: #fff;
  line-height: 1.6;
  margin: 0;
  padding: 0;
}

@media screen and (max-width: 768px) {
  body {
    padding: 0 1rem;
  }
}

header.header {
  background-color: #f5f5f5;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 20%;
}

main {
  max-width: 900px;
  margin: 2rem auto;
}

footer {
  background-color: #f5f5f5;
  padding: 1rem 20%;
  text-align: center;
}

nav {
  font-size: 1.5rem;
  font-weight: bold;
  padding: 0;
  margin: 0;
  width: 100%;
}

nav ul {
  list-style-type: none;
  padding: 0;
  margin: 0;
  display: flex;
}

nav ul li {
  margin: 0 1rem;
}

nav ul li:first-child {
  margin-right: auto;
}

nav ul li a {
  border: none;
  color: #000;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: bold;
}

p {
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: 1rem;
}

a {
  text-decoration: none;
  color: #000;
  border-bottom: 1px solid #000;
}

a:hover {
  color: #666;
}

pre {
  background-color: #f5f5f5;
  padding: 1rem;
  overflow-x: auto;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
}

blockquote {
  background-color: #f5f5f5;
  border-left: 5px solid #000;
  padding: 1rem;
  margin: 1rem 0;
}

.tag {
  display: inline-block;
  background-color: #f5f5f5;
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.9rem;
  margin-right: 5px;
  margin-bottom: 5px;
}

.tag a {
  border: none;
}

code {
  background-color: #f5f5f5;
  padding: 1px 4px;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
  border-radius: 2px;
}

li.revision {
  list-style: inside;
}

h1 {
  font-size: 2.0rem;
}

.post-content h2,
.post-content h3,
.post-content h4,
.post-content h5,
.post-content h6 {
  border-bottom: 1px solid #000;
  margin-bottom: 1rem;
}

.post-content h2 a,
.post-content h3 a,
.post-content h4 a,
.post-content h5 a,
.post-content h6 a {
  border: none;
}

.post-content h2:before {
  content: "#";
  padding-right: 0.3rem;
  color: #333;
  font-weight: bold;
}

.post-content h3:before {
  content: "##";
  padding-right: 0.3rem;
  color: #333;
  font-weight: bold;
}

.post-content h4:before {
  content: "###";
  padding-right: 0.3rem;
  color: #333;
  font-weight: bold;
}

.post-content h5:before {
  content: "####";
  padding-right: 0.3rem;
  color: #333;
  font-weight: bold;
}

.post-content h6:before {
  content: "#####";
  padding-right: 0.3rem;
  color: #333;
  font-weight: bold;
}

article.post-entry {
  background-color: #f5f5f5;
  border-radius: 10px;
  padding: 1.5rem;
  margin: 2rem 0;
}

.post-entry header {
  border: none;
}

.post-entry header h2 {
  margin: 0;
}

.post-entry section {
  color: #666;
}

.post-entry footer {
  background-color: #f5f5f5;
  padding: 0;
  text-align: left;
  color: #666;
}