/* Design tokens taken from techno-polis.com's rendered CSS custom properties
   (see docs/PLAN.md, "techno-polis.com's actual design tokens" section). */
:root {
  --color-bg: #ffffff;
  --color-text: #1d1e20;
  --color-text-strong: #18181a;
  --color-nav: #0d141a;
  --color-primary: #673de6;
  --color-primary-dark: #5025d1;
  --color-primary-light: #ebe4ff;
  --color-azure: #357df9;
  --color-azure-dark: #265ab2;
  --color-azure-light: #e3ebf9;
  --color-warning: #ffcd35;
  --color-warning-dark: #fea419;
  --color-border: #dadce0;
  --color-gray: #727586;
  --font-primary: 'Inter', sans-serif;
  --content-width: 780px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-primary);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.5;
}

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

a:hover {
  text-decoration: underline;
}

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

/* Header */
.site-header {
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  background: var(--color-bg);
  z-index: 10;
}

.site-header__inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.site-header__logo img {
  height: 48px;
  width: auto;
}

.site-header__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}

.site-header__nav a {
  color: var(--color-nav);
  font-size: 14px;
  font-weight: 500;
}

.site-header__nav a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.site-header__nav a.is-current {
  color: var(--color-primary);
}

/* Desktop header: proportions and link styling copied from techno-polis.com */
@media (min-width: 641px) {
  .site-header__inner {
    padding: 12px 28px 6px;
  }
  .site-header__logo img {
    width: 212px;
    height: auto;
  }
  .site-header__nav {
    gap: 32px;
  }
  .site-header__nav a {
    font-size: 16px;
    font-weight: 400;
    padding-bottom: 3px;
    border-bottom: 1px solid transparent;
  }
  .site-header__nav a:hover {
    color: var(--color-nav);
  }
  .site-header__nav a.is-current {
    color: var(--color-nav);
    border-bottom-color: var(--color-nav);
  }
}

.site-header__toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  background: none;
  cursor: pointer;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 6px;
}

.site-header__toggle span {
  display: block;
  width: 26px;
  height: 2px;
  background: var(--color-nav);
  transition: transform 0.2s, opacity 0.2s;
}

.site-header.is-open .site-header__toggle span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

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

.site-header.is-open .site-header__toggle span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Page header */
.page-title {
  max-width: var(--content-width);
  margin: 40px auto 8px;
  padding: 0 24px;
  font-size: 32px;
  font-weight: 700;
  color: var(--color-text-strong);
}

.page-subtitle {
  max-width: var(--content-width);
  margin: 0 auto 32px;
  padding: 0 24px;
  color: var(--color-gray);
  font-size: 15px;
}

.page-subtitle + .page-subtitle--links {
  margin-top: -24px;
}

.page-subtitle--links a {
  color: var(--color-azure-dark);
  font-weight: 500;
}

/* Article list (key4biz Dailyletter-style rows) */
.article-list {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 24px 40px;
}

.article-card {
  display: flex;
  gap: 20px;
  padding: 24px 0;
  border-bottom: 1px solid var(--color-border);
}

.article-card:first-child {
  padding-top: 0;
}

.article-card__cover {
  flex: 0 0 200px;
  aspect-ratio: 2 / 1;
  overflow: hidden;
  border-radius: 6px;
  background: var(--color-primary-light);
}

.article-card__cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.article-card__body {
  flex: 1;
  min-width: 0;
}

.article-card__title {
  margin: 0 0 8px;
  font-size: 19px;
  line-height: 1.3;
  font-weight: 600;
}

.article-card__title a {
  color: var(--color-text-strong);
}

.article-card__title a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.article-card__meta {
  font-size: 13px;
  color: var(--color-gray);
}

.article-card__meta a {
  color: var(--color-azure-dark);
  font-weight: 500;
}

.article-card__meta a:hover {
  text-decoration: none;
}

/* Pagination */
.pagination {
  max-width: var(--content-width);
  margin: 0 auto 60px;
  padding: 0 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
}

.pagination a,
.pagination span {
  min-width: 36px;
  height: 36px;
  padding: 0 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  font-size: 14px;
  color: var(--color-text);
}

.pagination a:hover {
  background: var(--color-primary-light);
  text-decoration: none;
}

.pagination .is-current {
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
}

.pagination .is-ellipsis {
  color: var(--color-gray);
}

/* Article detail page */
.article {
  max-width: var(--content-width);
  margin: 40px auto;
  padding: 0 24px;
}

.article__back {
  display: inline-block;
  margin-bottom: 24px;
  font-size: 14px;
  color: var(--color-azure-dark);
}

.article__category {
  display: inline-block;
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 16px;
}

.article__title {
  margin: 0 0 12px;
  font-size: 34px;
  line-height: 1.25;
  font-weight: 700;
  color: var(--color-text-strong);
}

.article__meta {
  color: var(--color-gray);
  font-size: 14px;
  margin-bottom: 28px;
}

.article__meta .author {
  color: var(--color-text);
  font-weight: 600;
}

.article__cover {
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 32px;
  background: var(--color-primary-light);
}

.article__cover img {
  width: 100%;
  height: auto;
}

.article__body {
  font-size: 17px;
  line-height: 1.7;
}

.article__body p {
  margin: 0 0 20px;
}

.article__h2 {
  margin: 36px 0 12px;
  font-size: 22px;
  line-height: 1.3;
  font-weight: 700;
  color: var(--color-text-strong);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  margin-top: 40px;
}

.site-footer__inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 32px 24px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.site-footer__tagline {
  font-weight: 600;
  color: var(--color-text-strong);
}

.site-footer__links {
  display: flex;
  gap: 20px;
  font-size: 13px;
  color: var(--color-gray);
}

.site-footer__links a {
  color: var(--color-gray);
}

.site-footer__copy {
  font-size: 13px;
  color: var(--color-gray);
  width: 100%;
}

/* Small screens */
@media (max-width: 640px) {
  .site-header {
    border-bottom: 0;
  }
  .site-header__logo img {
    width: 100px;
    height: auto;
  }
  .site-header__toggle {
    display: flex;
  }
  .site-header__nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    flex-direction: column;
    align-items: flex-end;
    gap: 0;
    padding: 24px 24px 32px;
    background: var(--color-bg);
    box-shadow: 0 12px 24px rgba(13, 20, 26, 0.08);
  }
  .site-header.is-open .site-header__nav {
    display: flex;
  }
  .site-header__nav a {
    font-size: 22px;
    font-weight: 400;
    padding: 14px 0;
  }
  .site-header__nav a.is-current {
    order: -1;
    color: var(--color-nav);
    border-bottom: 2px solid var(--color-nav);
    padding-bottom: 4px;
    margin-bottom: 10px;
  }
  .article-card {
    gap: 14px;
  }
  .article-card__cover {
    flex-basis: 120px;
  }
  .article-card__title {
    font-size: 16px;
  }
  .article__title {
    font-size: 26px;
  }
}