:root {
  --color-bg: #f7fbff;
  --color-bg-soft: #eef6fc;
  --color-surface: #ffffff;
  --color-text: #15263d;
  --color-text-soft: #5f6f82;
  --color-primary: #2f90d0;
  --color-primary-dark: #1e6fa7;
  --color-accent: #ef8a77;
  --color-line: #dce8f1;
  --font-heading: "Zen Kaku Gothic New", "Noto Sans JP", sans-serif;
  --font-body: "Noto Sans JP", sans-serif;
  --container: 1180px;
  --article-container: 820px;
  --radius-sm: 12px;
  --radius-md: 22px;
  --shadow-card: 0 14px 34px rgba(44, 85, 122, 0.09);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--color-text);
  background: var(--color-surface);
  font-family: var(--font-body);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: var(--color-primary-dark);
  text-decoration: none;
}

a:hover {
  color: var(--color-primary);
}

.container {
  width: min(calc(100% - 48px), var(--container));
  margin-inline: auto;
}

/* GLOBAL HEADER */

.site-header{
  position:sticky;
  top:0;
  z-index:1000;
  border-bottom:1px solid rgba(220,232,241,.72);
  background:rgba(255,255,255,.90);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
  transition:
    background-color .25s ease,
    box-shadow .25s ease,
    border-color .25s ease;
}

.site-header.is-scrolled{
  border-bottom-color:rgba(208,224,236,.88);
  background:rgba(255,255,255,.96);
  box-shadow:0 8px 28px rgba(44,85,122,.07);
}

.site-header__inner{
  position:relative;
  display:flex;
  min-height:76px;
  align-items:center;
  justify-content:space-between;
  gap:36px;
}

.site-header__brand{
  display:inline-flex;
  flex:0 0 auto;
  align-items:center;
}

.site-header__brand img{
  width:138px;
  height:auto;
}

.site-nav{
  display:flex;
  align-items:center;
  gap:30px;
}

.site-nav a{
  position:relative;
  padding:7px 0;
  color:var(--color-text-soft);
  font-size:.75rem;
  font-weight:700;
  line-height:1.4;
  letter-spacing:.12em;
  transition:color .2s ease;
}

.site-nav a::after{
  position:absolute;
  right:0;
  bottom:0;
  left:0;
  height:1px;
  background:var(--color-primary);
  content:"";
  transform:scaleX(0);
  transform-origin:right center;
  transition:transform .25s ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a[aria-current="page"]{
  color:var(--color-primary-dark);
}

.site-nav a:hover::after,
.site-nav a:focus-visible::after,
.site-nav a[aria-current="page"]::after{
  transform:scaleX(1);
  transform-origin:left center;
}

.site-header__toggle{
  display:none;
  width:44px;
  height:44px;
  align-items:center;
  justify-content:center;
  flex-direction:column;
  gap:5px;
  padding:0;
  border:0;
  border-radius:12px;
  color:var(--color-text);
  background:transparent;
  cursor:pointer;
}

.site-header__toggle span{
  display:block;
  width:21px;
  height:2px;
  border-radius:999px;
  background:currentColor;
  transition:
    transform .25s ease,
    opacity .2s ease;
}

.site-header.is-menu-open .site-header__toggle span:nth-child(1){
  transform:translateY(7px) rotate(45deg);
}

.site-header.is-menu-open .site-header__toggle span:nth-child(2){
  opacity:0;
}

.site-header.is-menu-open .site-header__toggle span:nth-child(3){
  transform:translateY(-7px) rotate(-45deg);
}

@media(max-width:820px){
  .site-header__inner{
    min-height:66px;
  }

  .site-header__brand img{
    width:124px;
  }

  .site-header__toggle{
    display:flex;
    position:relative;
    z-index:2;
  }

  .site-nav{
    position:absolute;
    top:calc(100% + 1px);
    right:0;
    left:0;
    display:flex;
    flex-direction:column;
    gap:0;
    align-items:stretch;
    padding:10px 22px 16px;
    border:1px solid rgba(220,232,241,.92);
    border-top:0;
    border-radius:0 0 22px 22px;
    background:rgba(255,255,255,.98);
    box-shadow:0 22px 40px rgba(44,85,122,.12);
    opacity:0;
    visibility:hidden;
    pointer-events:none;
    transform:translateY(-8px);
    transition:
      opacity .2s ease,
      visibility .2s ease,
      transform .2s ease;
  }

  .site-header.is-menu-open .site-nav{
    opacity:1;
    visibility:visible;
    pointer-events:auto;
    transform:translateY(0);
  }

  .site-nav a{
    display:block;
    padding:15px 2px;
    border-bottom:1px solid var(--color-line);
    font-size:.78rem;
    letter-spacing:.14em;
  }

  .site-nav a:last-child{
    border-bottom:0;
  }

  .site-nav a::after{
    display:none;
  }
}

@media(max-width:680px){
  .site-header__inner{
    min-height:62px;
  }

  .site-header__brand img{
    width:116px;
  }

  .site-header__toggle{
    width:42px;
    height:42px;
  }

  .site-nav{
    padding-inline:18px;
    border-radius:0 0 18px 18px;
  }
}

/* Page hero */


.article-page-hero {
  padding: 88px 0 72px;
  border-bottom: 1px solid var(--color-line);
  background:
    radial-gradient(
      circle at 78% 20%,
      rgba(47, 144, 208, 0.11),
      transparent 34%
    ),
    linear-gradient(180deg, #f7fbff 0%, #ffffff 100%);
}

.article-page-hero__eyebrow {
  margin: 0 0 16px;
  color: var(--color-primary-dark);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.18em;
}

.article-page-hero h1 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(2.25rem, 5vw, 4rem);
  line-height: 1.35;
  letter-spacing: -0.04em;
}

.article-page-hero__lead {
  max-width: 660px;
  margin: 22px 0 0;
  color: var(--color-text-soft);
  font-size: 1rem;
}

/* Main */

.article-main {
  padding: 72px 0 104px;
  background: var(--color-surface);
}

/* Footer */

.footer {
  margin-top: 0;
  color: rgba(255, 255, 255, 0.82);
  background: linear-gradient(180deg, #173a5c 0%, #12263d 100%);
}

.footer__inner {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 80px;
  align-items: start;
  padding: 72px 0 56px;
}

.footer__brand {
  max-width: 200px;
}

.footer__brand img {
  width: 200px;
  height: auto;
}

.footer__message {
  width: 200px;
  margin-top: 22px;
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.7rem;
  line-height: 1.8;
  text-align: center;
}

.footer__message strong {
  display: block;
  margin-bottom: 6px;
  color: #fff;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.footer__menu {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 56px;
}

.footer__column h2 {
  margin: 0 0 22px;
  color: #fff;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
}

.footer__column ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer__column li + li {
  margin-top: 14px;
}

.footer__column a {
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.93rem;
  line-height: 1.8;
  transition: color 0.25s;
}

.footer__column a:hover {
  color: #fff;
}

.footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer__bottom .container {
  padding: 24px 0;
  text-align: center;
}

.footer__bottom small {
  color: rgba(255, 255, 255, 0.52);
  font-size: 0.78rem;
}

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 999;
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--color-primary);
  box-shadow: 0 10px 25px rgba(30, 111, 167, 0.26);
  opacity: 0;
  pointer-events: none;
  transition:
    opacity 0.25s,
    transform 0.25s,
    background 0.25s;
}

.back-to-top:hover {
  color: #fff;
  background: var(--color-primary-dark);
  transform: translateY(-4px);
}

@media (max-width: 760px) {
  .container {
    width: min(calc(100% - 32px), var(--container));
  }

  .article-page-hero {
    padding: 64px 0 54px;
  }

  .article-main {
    padding: 52px 0 76px;
  }

  .footer__inner {
    grid-template-columns: 1fr;
    gap: 46px;
    padding: 56px 0 40px;
  }

  .footer__brand {
    width: 200px;
    max-width: 100%;
    margin: 0 auto;
    text-align: center;
  }

  .footer__brand img {
    width: 160px;
    margin: 0 auto;
  }

  .footer__message {
    width: 100%;
  }

  .footer__menu {
    grid-template-columns: 1fr;
    gap: 38px;
    text-align: center;
  }

  .back-to-top {
    right: 16px;
    bottom: 16px;
  }
}

/* Category filter */

.category-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 48px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--color-line);
}

.category-filter__item {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  padding: 8px 18px;
  border: 1px solid var(--color-line);
  border-radius: 999px;
  color: var(--color-text-soft);
  background: #fff;
  font-size: 0.86rem;
  font-weight: 600;
  transition:
    color 0.2s,
    border-color 0.2s,
    background 0.2s,
    transform 0.2s;
}

.category-filter__item:hover {
  border-color: rgba(47, 144, 208, 0.5);
  color: var(--color-primary-dark);
  background: var(--color-bg);
  transform: translateY(-1px);
}

.category-filter__item.is-active {
  border-color: var(--color-primary);
  color: #fff;
  background: var(--color-primary);
}

/* Article list */

.article-list {
  border-top: 1px solid var(--color-line);
}

.article-list-item {
  padding: 42px 8px;
  border-bottom: 1px solid var(--color-line);
}

.article-list-item__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
  align-items: center;
  margin-bottom: 16px;
  color: var(--color-text-soft);
  font-size: 0.82rem;
}

.article-category {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  padding: 4px 11px;
  border-radius: 999px;
  color: var(--color-primary-dark);
  background: var(--color-bg-soft);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.article-category:hover {
  color: #fff;
  background: var(--color-primary);
}

.article-list-item__title {
  max-width: 880px;
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(1.35rem, 2.5vw, 1.85rem);
  line-height: 1.55;
  letter-spacing: -0.025em;
}

.article-list-item__title a {
  color: var(--color-text);
}

.article-list-item__title a:hover {
  color: var(--color-primary-dark);
}

.article-list-item__excerpt {
  max-width: 800px;
  margin: 18px 0 0;
  color: var(--color-text-soft);
  font-size: 0.95rem;
  line-height: 1.95;
}

.article-list-item__link {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  margin-top: 22px;
  color: var(--color-primary-dark);
  font-size: 0.86rem;
  font-weight: 700;
}

.article-list-item__link span {
  transition: transform 0.2s;
}

.article-list-item__link:hover span {
  transform: translateX(4px);
}

/* Empty */

.article-empty {
  padding: 64px 24px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  text-align: center;
}

.article-empty p {
  margin: 0;
  color: var(--color-text-soft);
}

/* Pagination */

.pagination {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-top: 56px;
}

.pagination__item {
  display: inline-flex;
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-line);
  border-radius: 50%;
  color: var(--color-text-soft);
  background: #fff;
  font-size: 0.84rem;
  font-weight: 600;
}

.pagination__item:hover {
  border-color: var(--color-primary);
  color: var(--color-primary-dark);
  background: var(--color-bg);
}

.pagination__item.is-active {
  border-color: var(--color-primary);
  color: #fff;
  background: var(--color-primary);
}

.pagination__item--wide {
  width: auto;
  min-width: 66px;
  padding-inline: 14px;
  border-radius: 999px;
}

@media (max-width: 760px) {
  .category-filter {
    gap: 8px;
    margin-bottom: 34px;
    padding-bottom: 22px;
  }

  .category-filter__item {
    min-height: 38px;
    padding: 7px 14px;
    font-size: 0.8rem;
  }

  .article-list-item {
    padding: 34px 2px;
  }

  .article-list-item__meta {
    gap: 10px 14px;
    margin-bottom: 13px;
  }

  .article-list-item__excerpt {
    font-size: 0.9rem;
    line-height: 1.85;
  }

  .pagination {
    margin-top: 44px;
  }

  .pagination__item {
    width: 38px;
    height: 38px;
  }

  .pagination__item--wide {
    width: auto;
  }
}

/* Article detail */

.article-detail-main {
  background: var(--color-surface);
}

.article-detail__header {
  padding: 72px 0 56px;
  border-bottom: 1px solid var(--color-line);
  background:
    radial-gradient(
      circle at 80% 18%,
      rgba(47, 144, 208, 0.1),
      transparent 32%
    ),
    linear-gradient(180deg, var(--color-bg) 0%, #fff 100%);
}

.article-detail__inner {
  width: min(
    calc(100% - 48px),
    var(--article-container)
  );
  margin-inline: auto;
}

.article-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 34px;
  color: var(--color-text-soft);
  font-size: 0.78rem;
}

.article-breadcrumb a {
  color: var(--color-text-soft);
}

.article-breadcrumb a:hover {
  color: var(--color-primary-dark);
}

.article-detail__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
  align-items: center;
  margin-bottom: 20px;
  color: var(--color-text-soft);
  font-size: 0.84rem;
}

.article-detail h1 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(2rem, 4.5vw, 3.5rem);
  line-height: 1.45;
  letter-spacing: -0.04em;
}

.article-detail__lead {
  margin: 26px 0 0;
  color: var(--color-text-soft);
  font-size: 1.04rem;
  line-height: 2;
}

.article-detail__updated {
  margin: 18px 0 0;
  color: var(--color-text-soft);
  font-size: 0.78rem;
}

.article-detail__featured {
  width: min(
    calc(100% - 48px),
    980px
  );
  margin: 64px auto 0;
}

.article-detail__featured img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
}

.article-body {
  padding: 72px 0 96px;
  color: var(--color-text);
  font-size: 1rem;
  line-height: 2.05;
}

.article-body > :first-child {
  margin-top: 0;
}

.article-body > :last-child {
  margin-bottom: 0;
}

.article-body p {
  margin: 0 0 1.8em;
}

.article-body h2 {
  margin: 3.2em 0 1.2em;
  padding-bottom: 0.55em;
  border-bottom: 2px solid var(--color-line);
  font-family: var(--font-heading);
  font-size: clamp(1.55rem, 3vw, 2rem);
  line-height: 1.55;
  letter-spacing: -0.025em;
}

.article-body h3 {
  margin: 2.7em 0 1em;
  padding-left: 16px;
  border-left: 4px solid var(--color-primary);
  font-family: var(--font-heading);
  font-size: clamp(1.25rem, 2.4vw, 1.55rem);
  line-height: 1.6;
}

.article-body strong {
  font-weight: 700;
}

.article-body a {
  color: var(--color-primary-dark);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.article-body a:hover {
  color: var(--color-primary);
}

.article-body ul,
.article-body ol {
  margin: 1.8em 0;
  padding-left: 1.6em;
}

.article-body li {
  margin: 0.55em 0;
  padding-left: 0.25em;
}

.article-body blockquote {
  margin: 2.4em 0;
  padding: 24px 28px;
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--color-text-soft);
  background: var(--color-bg);
}

.article-body blockquote > :last-child {
  margin-bottom: 0;
}

.article-body img {
  max-width: 100%;
  height: auto;
  margin: 2.6em auto;
  border-radius: var(--radius-sm);
}

.article-body hr {
  margin: 4em 0;
  border: 0;
  border-top: 1px solid var(--color-line);
}

.article-body pre {
  overflow-x: auto;
  margin: 2.4em 0;
  padding: 22px 24px;
  border-radius: var(--radius-sm);
  color: #eaf3fa;
  background: #12263d;
  font-size: 0.88rem;
  line-height: 1.75;
}

.article-body code {
  font-family:
    SFMono-Regular,
    Consolas,
    "Liberation Mono",
    monospace;
}

.article-body :not(pre) > code {
  padding: 0.18em 0.42em;
  border-radius: 5px;
  color: var(--color-primary-dark);
  background: var(--color-bg-soft);
  font-size: 0.9em;
}

.article-body table {
  width: 100%;
  margin: 2.5em 0;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.article-body th,
.article-body td {
  padding: 14px 16px;
  border: 1px solid var(--color-line);
  text-align: left;
  vertical-align: top;
}

.article-body th {
  background: var(--color-bg-soft);
  font-weight: 700;
}

.article-detail__footer {
  padding: 0 0 96px;
  border-top: 1px solid var(--color-line);
}

.article-back-link {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  margin-top: 36px;
  color: var(--color-primary-dark);
  font-size: 0.9rem;
  font-weight: 700;
}

.article-back-link span {
  transition: transform 0.2s;
}

.article-back-link:hover span {
  transform: translateX(-4px);
}

@media (max-width: 760px) {
  .article-detail__header {
    padding: 52px 0 42px;
  }

  .article-detail__inner {
    width: min(
      calc(100% - 32px),
      var(--article-container)
    );
  }

  .article-breadcrumb {
    margin-bottom: 26px;
  }

  .article-detail__lead {
    font-size: 0.96rem;
    line-height: 1.9;
  }

  .article-detail__featured {
    width: calc(100% - 32px);
    margin-top: 42px;
  }

  .article-body {
    padding: 54px 0 72px;
    font-size: 0.96rem;
    line-height: 1.95;
  }

  .article-body h2 {
    margin-top: 2.8em;
  }

  .article-body h3 {
    margin-top: 2.4em;
  }

  .article-body blockquote {
    padding: 20px;
  }

  .article-body table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }

  .article-detail__footer {
    padding-bottom: 72px;
  }
}

/* Article list thumbnail */

.article-list-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 48px;
  align-items: center;
}

.article-list-item__content {
  min-width: 0;
}

.article-list-item__thumbnail {
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-sm);
  background: var(--color-bg-soft);
}

.article-list-item__thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.35s ease;
}

.article-list-item__thumbnail:hover img {
  transform: scale(1.035);
}

.article-list-item:not(:has(.article-list-item__thumbnail)) {
  grid-template-columns: minmax(0, 1fr);
}

@media (max-width: 760px) {
  .article-list-item {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .article-list-item__thumbnail {
    grid-row: 1;
  }

  .article-list-item__content {
    grid-row: 2;
  }
}

/* Featured image size adjustment */

.article-detail__featured {
  width: min(
    calc(100% - 48px),
    var(--article-container)
  );
}

.article-detail__featured img {
  width: 100%;
  max-height: 520px;
  object-fit: cover;
}

@media (max-width: 760px) {
  .article-detail__featured {
    width: calc(100% - 32px);
  }

  .article-detail__featured img {
    max-height: 360px;
  }
}

/* Previous and next articles */

.article-neighbors {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  padding: 40px 0;
  border-bottom: 1px solid var(--color-line);
}

.article-neighbors__item {
  min-width: 0;
}

.article-neighbors__item--next {
  text-align: right;
}

.article-neighbors__item a {
  display: block;
  height: 100%;
  padding: 22px 24px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  transition:
    border-color 0.2s,
    transform 0.2s,
    box-shadow 0.2s;
}

.article-neighbors__item a:hover {
  border-color: rgba(47, 144, 208, 0.45);
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.article-neighbors__label {
  display: block;
  margin-bottom: 8px;
  color: var(--color-primary-dark);
  font-size: 0.76rem;
  font-weight: 700;
}

.article-neighbors__item strong {
  display: block;
  color: var(--color-text);
  font-family: var(--font-heading);
  font-size: 0.94rem;
  line-height: 1.65;
}

.article-back-link {
  display: table;
  margin: 34px auto 0;
}

@media (max-width: 760px) {
  .article-neighbors {
    grid-template-columns: 1fr;
    gap: 14px;
    padding: 30px 0;
  }

  .article-neighbors__item--next {
    text-align: left;
  }
}