/* Design tokens from .agents/DESIGN.md */

:root {
  --color-primary: #1c1917;
  --color-secondary: #78716c;
  --color-surface: #ffffff;
  --color-surface-muted: #fafaf9;
  --color-surface-hover: #f5f5f4;
  --color-border: #e7e5e4;
  --color-selection: #f5f5f4;

  --font-title: "IBM Plex Sans", sans-serif;
  --font-body: "IBM Plex Sans JP", sans-serif;

  --radius-sm: 9999px;
  --radius-md: 16px;
  --radius-lg: 32px;
  --radius-xl: 40px;

  --content-max-width: 720px;
  --card-padding: 16px;
  --card-height: 96px;
  --card-shadow: 0 0 25px rgba(22, 22, 22, 0.06);
  --section-gap: 16px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 0.2s var(--ease-out);
  --transition-normal: 0.3s var(--ease-out);
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.74;
  color: var(--color-primary);
  background-color: var(--color-surface);
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

::selection {
  background-color: var(--color-selection);
}

a {
  color: inherit;
  text-decoration: none;
}

img,
svg {
  display: block;
  max-width: 100%;
  border-radius: var(--radius-lg);
  -webkit-user-drag: none;
}

.container {
  width: 100%;
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: 20px;
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background-color: color-mix(in srgb, var(--color-surface) 80%, transparent);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.site-header__panel {
  padding-bottom: 12px;
}

.site-title {
  font-family: var(--font-title);
  font-size: 1.45rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  transition: opacity var(--transition-fast);
}

.site-title:hover {

}

/* Icon button */

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-primary);
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.icon-btn:hover {
  background-color: var(--color-surface-hover);
}

.icon-btn:active {
  transform: scale(0.97);
}

.icon-btn svg {
  width: 18px;
  height: 18px;
}

/* Main layout */

.site-main {
  min-height: 90vh;
}

.section-gap {
  display: flex;
  flex-direction: column;
  gap: var(--section-gap);
}

/* Header actions */

.header-action-btn {
  position: relative;
}

.header-action-btn.is-active,
.header-action-btn.has-query {
  background-color: var(--color-surface-hover);
}

.header-action-btn.has-query::after {
  content: "";
  position: absolute;
  top: 7px;
  right: 7px;
  width: 5px;
  height: 5px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
}

.expand-panel.is-open {
  animation: slideUp 0.3s var(--ease-out) both;
}

/* Search */

.search {
  position: relative;
}

.search__input {
  width: 100%;
  padding: 12px 44px 12px 16px;
  font-family: var(--font-body);
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--color-primary);
  background-color: var(--color-surface-muted);
  border: none;
  border-radius: var(--radius-md);
  outline: none;
  transition: background-color var(--transition-fast);
}

.search__input::-webkit-search-cancel-button {
  -webkit-appearance: none;
  appearance: none;
  display: none;
}

.search__input::-moz-search-clear-button {
  display: none;
}

.search__input::placeholder {
  color: var(--color-secondary);
}

.search__input:focus {
  background-color: var(--color-surface-hover);
}

.search__clear {
  position: absolute;
  top: 50%;
  right: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  padding: 0;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-secondary);
  cursor: pointer;
  transform: translateY(-50%);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.search__clear:hover {
  background-color: var(--color-surface-hover);
  color: var(--color-primary);
}

.search__clear svg {
  width: 14px;
  height: 14px;
  border-radius: 0;
}

/* Article cards */

.article-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.article-card {
  height: var(--card-height);
  /* box-shadow: var(--card-shadow); */
}

.article-card.is-hidden {
  display: none;
}

.article-card__link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  height: 100%;
}

.article-card__title {
  flex: 1;
  min-width: 0;
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  line-height: 1.4;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.article-card__date {
  flex-shrink: 0;
  font-size: 1rem;
  font-weight: 400;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
  font-family: "IBM Plex Sans";
  white-space: nowrap;
}

/* Empty state */

.empty-state {
  padding: var(--card-padding);
  text-align: center;
  color: var(--color-secondary);
}

.empty-state.is-hidden {
  display: none;
}

/* Single post */
.post-content {
  padding-bottom: 64px;
}

.post-header {
  margin-bottom: var(--section-gap);
}

.post-header__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 8px;
}

.post-header__date,
.post-header__category {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--color-secondary);
}

.post-header__category::before {
  content: "#";
  margin-right: 8px;
}

.post-header__title {
  margin: 0;
  font-family: var(--font-title);
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.3;
  margin-bottom: 24px;
}

/* Prose */

.prose {
  color: var(--color-primary);
}

.prose > *:first-child {
  margin-top: 0;
}

.prose > *:last-child {
  margin-bottom: 0;
}

.prose h2 {
  margin: 2em 0 0.75em;
  font-family: var(--font-title);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.4;
}

.prose h3 {
  margin: 1.5em 0 0.5em;
  font-family: var(--font-title);
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.prose p {
  margin: 0 0 1.25em;
  line-height: 1.75em;
  letter-spacing: 0.02em;
}

.prose a {
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: opacity var(--transition-fast);
}

.prose a:hover {
  opacity: 0.7;
}

.prose ul,
.prose ol {
  margin: 0 0 1.25em;
  padding-left: 1.5em;
}

.prose li {
  margin-bottom: 0.5em;
}

.prose blockquote {
  margin: 1.5em 0;
  padding-left: 1em;
  border-left: 2px solid var(--color-border);
  color: var(--color-secondary);
}

.prose code {
  font-size: 0.875em;
  padding: 0.15em 0.4em;
  background-color: var(--color-surface-muted);
  border-radius: 4px;
}

.prose pre {
  margin: 1.5em 0;
  padding: 1em;
  overflow-x: auto;
  font-size: 0.8125rem;
  line-height: 1.6;
  background-color: var(--color-surface-muted);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.prose pre code {
  padding: 0;
  background: none;
  border-radius: 0;
}

/* Footer */

.site-footer {
  padding-block: 24px;
  border-top: 1px solid var(--color-border);
  height: 80px;
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.site-footer__text,
.site-footer__link {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-secondary);
  transition: color var(--transition-fast);
}

.site-footer__link:hover {
  color: var(--color-primary);
}

/* 404 */

.error-page {
  padding-block: 64px;
  text-align: center;
  animation: slideUp 0.5s var(--ease-out) both;
}

.error-page__code {
  margin: 0 0 8px;
  font-family: var(--font-title);
  font-size: 3rem;
  font-weight: 600;
  letter-spacing: -0.04em;
}

.error-page__message {
  margin: 0 0 24px;
  color: var(--color-secondary);
}

/* Stagger animation for cards */

.article-list .article-card:nth-child(1) { animation-delay: 0s; }
.article-list .article-card:nth-child(2) { animation-delay: 0.05s; }
.article-list .article-card:nth-child(3) { animation-delay: 0.1s; }
.article-list .article-card:nth-child(4) { animation-delay: 0.15s; }
.article-list .article-card:nth-child(5) { animation-delay: 0.2s; }