/*
  Series A website styles
  -----------------------
  Main goals:
  1. Keep the layout simple and professional.
  2. Make the header larger and clearer than the old version.
  3. Preserve easy maintenance for static hosting.
*/
:root {
  --primary: #1f3b6d;
  --primary-dark: #27497f;
  --primary-soft: #e8f0fb;
  --accent: #79a7ff;
  --bg: #eef2f6;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-solid: #ffffff;
  --border: #d7dee8;
  --text: #1f2937;
  --muted: #5f6b7a;
  --shadow: 0 16px 36px rgba(31, 41, 55, 0.08);
}

html {
  scroll-behavior: smooth;
}
body.site-body {
  font-family:
    'Inter',
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    'Segoe UI',
    sans-serif;
  background: var(--bg);
  color: var(--text);
}

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

.site-header {
  z-index: 1030;
}
.site-navbar {
  background: var(--primary);
  min-height: 86px;
  box-shadow: 0 6px 20px rgba(17, 24, 39, 0.14);
}
.brand-mark {
  width: 44px;
  height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.18);
  color: #fff;
  font-weight: 800;
  font-size: 1.1rem;
  border: 1px solid rgba(255, 255, 255, 0.16);
}
.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.05;
}
.brand-text small {
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.brand-text strong {
  color: #fff;
  font-size: 1.22rem;
  letter-spacing: 0.02em;
}
.site-navbar .nav-link,
.site-navbar .navbar-brand {
  color: rgba(255, 255, 255, 0.95) !important;
}
.site-navbar .nav-link {
  position: relative;
  padding: 1rem 1rem !important;
  font-weight: 700;
  font-size: 0.97rem;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}
.site-navbar .nav-link:hover,
.site-navbar .nav-link.active {
  color: #fff !important;
}
.site-navbar .nav-link::after {
  content: '';
  position: absolute;
  left: 1rem;
  right: 1rem;
  bottom: 0.62rem;
  height: 2px;
  transform: scaleX(0);
  transform-origin: center;
  background: var(--accent);
  transition: transform 0.22s ease;
}
.site-navbar .nav-link:hover::after,
.site-navbar .nav-link.active::after {
  transform: scaleX(1);
}

.page-shell {
  padding: 3.7rem 0 5rem;
}
.page-card,
.content-panel,
.contact-panel {
  background: var(--surface);
  border: 1px solid rgba(255, 255, 255, 0.7);
  border-radius: 24px;
  box-shadow: var(--shadow);
}
.page-card {
  padding: 2rem;
}
.content-panel,
.contact-panel {
  padding: 1.5rem;
}
.hero-title,
.section-title {
  color: var(--primary);
  font-family: 'Inter', sans-serif;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  line-height: 1.08;
}
.hero-title {
  font-size: clamp(2.1rem, 4vw, 3.55rem);
  margin-bottom: 1.25rem;
}
.section-title {
  font-size: clamp(1.8rem, 3vw, 2.7rem);
  margin-bottom: 1.1rem;
}
.series-line {
  color: var(--primary);
  font-size: clamp(1.2rem, 2vw, 1.75rem);
  font-weight: 700;
  margin-bottom: 1.2rem;
}
.lead-line {
  font-size: 1.3rem;
  line-height: 1.5;
  font-weight: 700;
  color: #111827;
  margin-bottom: 0.7rem;
}
.copy-block p,
.contact-list p,
.person-card p,
.accordion-body,
.archive-link,
.helper-note {
  font-size: 1.06rem;
  line-height: 1.88;
}
.cover-image {
  width: 100%;
  max-width: 350px;
  border-radius: 8px;
  box-shadow: 0 18px 34px rgba(17, 24, 39, 0.18);
}
.meta-box {
  margin-top: 1.75rem;
  padding: 1rem 1.15rem;
  background: var(--surface-solid);
  border: 1px solid var(--border);
  border-radius: 18px;
}
.meta-box p {
  margin-bottom: 0.45rem;
  font-size: 1.05rem;
}
.panel-title {
  color: var(--primary);
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 1rem;
}
.person-card {
  margin-bottom: 1.6rem;
}
.person-card:last-child {
  margin-bottom: 0;
}
.person-card h3 {
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: 0.45rem;
}
.accordion-item {
  border: 1px solid var(--border);
  border-radius: 18px !important;
  overflow: hidden;
  margin-bottom: 1rem;
  background: var(--surface-solid);
}
.accordion-button {
  font-weight: 700;
  color: var(--primary);
  background: var(--surface-solid);
}
.accordion-button:not(.collapsed) {
  color: var(--primary-dark);
  background: var(--primary-soft);
  box-shadow: none;
}
.accordion-button:focus {
  box-shadow: none;
}

.archive-group {
  margin-bottom: 1.45rem;
}
.archive-year {
  color: #374151;
  font-weight: 800;
  font-size: 1.1rem;
  margin-bottom: 0.3rem;
}
.archive-link {
  display: block;
  color: #274d79;
  text-decoration: none;
  transition:
    transform 0.18s ease,
    color 0.18s ease;
}
.archive-link:hover {
  color: var(--primary);
  transform: translateX(4px);
}
.archive-link.is-empty {
  opacity: 0.9;
}
.archive-link.is-empty::after {
  content: '  (add link)';
  color: var(--muted);
  font-size: 0.9rem;
}
.helper-note {
  margin-top: 2rem;
  color: var(--muted);
}
.map-frame {
  width: 100%;
  min-height: 315px;
  border: 0;
  border-radius: 18px;
}
.form-label {
  font-weight: 700;
}
.form-control {
  min-height: 50px;
  border-radius: 14px;
  border-color: var(--border);
}
textarea.form-control {
  min-height: 150px;
}
.form-control:focus {
  border-color: #91b2ea;
  box-shadow: 0 0 0 0.2rem rgba(31, 95, 151, 0.12);
}
.btn-primary {
  background: #5f92f3;
  border-color: #5f92f3;
  min-height: 52px;
  border-radius: 14px;
  font-weight: 700;
}
.btn-primary:hover,
.btn-primary:focus {
  background: #4d82e8;
  border-color: #4d82e8;
}
.alert {
  border-radius: 16px;
}
.site-footer {
  background: var(--primary);
  color: rgba(255, 255, 255, 0.94);
  text-align: center;
  padding: 1.8rem 0;
}
.site-footer p {
  margin: 0;
  font-size: 0.98rem;
}

@media (max-width: 991.98px) {
  .site-navbar {
    min-height: 76px;
  }
  .site-navbar .nav-link {
    padding: 0.75rem 0.4rem !important;
    font-size: 0.94rem;
  }
  .site-navbar .nav-link::after {
    left: 0.4rem;
    right: auto;
    width: 68px;
    bottom: 0.3rem;
  }
  .page-shell {
    padding: 2.5rem 0 3.8rem;
  }
  .page-card {
    padding: 1.35rem;
  }
  .lead-line {
    font-size: 1.08rem;
  }
  .copy-block p,
  .contact-list p,
  .person-card p,
  .accordion-body,
  .archive-link {
    font-size: 1rem;
    line-height: 1.78;
  }
}

/*
  Archive detail pages
  --------------------
  These blocks style the issue overview page and each article detail page.
  They are separated from the global page styles so later archive volumes can
  reuse the same visual system without touching the main pages.
*/
.issue-page-shell,
.article-page-shell {
  padding-top: 2.8rem;
}
.issue-page-wrap,
.article-page-wrap {
  max-width: 1380px;
}
.issue-volume-title {
  color: var(--primary);
  font-size: clamp(2rem, 3vw, 3.1rem);
  font-weight: 800;
  margin-bottom: 1.8rem;
}
.issue-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 2rem;
  align-items: start;
}
.issue-main-column {
  min-width: 0;
}
.issue-article-card {
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid #e1e7ef;
  border-radius: 14px;
  box-shadow: 0 8px 18px rgba(31, 41, 55, 0.05);
  padding: 1.5rem 1.5rem 1.2rem;
  margin-bottom: 1.8rem;
}
.issue-article-title {
  font-size: clamp(1.5rem, 2.1vw, 2.6rem);
  line-height: 1.12;
  font-weight: 500;
  margin-bottom: 1rem;
}
.issue-article-title a {
  color: var(--primary);
  text-decoration: none;
}
.issue-article-title a:hover {
  color: var(--primary-dark);
}
.issue-meta,
.issue-keywords {
  margin-bottom: 0.35rem;
  font-size: 1.02rem;
}
.issue-keywords {
  color: #5f92f3;
}
.issue-side-column {
  position: sticky;
  top: 110px;
}
.issue-cover-box {
  text-align: center;
}
.issue-cover-image,
.article-cover-image {
  width: 100%;
  max-width: 285px;
  box-shadow: 0 10px 26px rgba(17, 24, 39, 0.1);
}
.issue-side-title {
  color: var(--primary);
  font-size: clamp(1.55rem, 1.8vw, 2.1rem);
  font-weight: 800;
  line-height: 1.06;
  margin: 1.15rem 0 0;
  text-transform: uppercase;
}
.article-detail-layout {
  display: grid;
  grid-template-columns: 380px minmax(0, 1fr);
  gap: 2.8rem;
  align-items: start;
}
.article-content-column {
  min-width: 0;
}
.article-breadcrumb a {
  text-decoration: none;
}
.article-breadcrumb span {
  margin: 0 0.35rem;
  color: var(--muted);
}
.article-detail-title {
  color: var(--primary);
  font-size: clamp(2rem, 3vw, 4rem);
  font-weight: 800;
  line-height: 1.08;
  margin-bottom: 1.25rem;
}
.article-detail-meta {
  font-size: clamp(1.05rem, 1.3vw, 1.4rem);
  margin-bottom: 0.5rem;
}
.article-detail-keywords {
  color: #4b5563;
}
.article-download-wrap {
  margin: 1.4rem 0 3rem;
}
.article-download-link {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--primary);
  font-size: clamp(1.2rem, 1.6vw, 1.8rem);
  font-weight: 800;
  text-decoration: none;
}
.article-download-link::before {
  content: '📄';
  font-size: 2rem;
  line-height: 1;
}
.article-abstract-title {
  color: var(--primary);
  font-size: clamp(1.6rem, 2vw, 2.5rem);
  font-weight: 800;
  margin-bottom: 1rem;
}
.article-abstract-block p {
  font-size: clamp(1.1rem, 1.45vw, 1.5rem);
  line-height: 1.75;
  margin-bottom: 0;
}
@media (max-width: 1199.98px) {
  .issue-layout {
    grid-template-columns: 1fr 280px;
  }
  .article-detail-layout {
    grid-template-columns: 300px minmax(0, 1fr);
    gap: 2rem;
  }
}
@media (max-width: 991.98px) {
  .issue-layout,
  .article-detail-layout {
    grid-template-columns: 1fr;
  }
  .issue-side-column {
    position: static;
  }
  .issue-cover-box,
  .article-cover-column {
    text-align: center;
  }
  .article-detail-title {
    font-size: clamp(1.9rem, 6vw, 3rem);
  }
}

/* Archive article placeholder note */
.article-placeholder-note {
  margin: 1rem 0 1.25rem;
  padding: 0.9rem 1rem;
  border-left: 4px solid #1f5f97;
  background: #eef5fb;
  color: #214766;
  border-radius: 0.5rem;
}
.article-placeholder-note code {
  color: #143852;
  word-break: break-all;
}


.doi-link {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 2px;
}
.article-placeholder-note a.doi-link {
  font-weight: 700;
}