/* AI協作觀察誌 — 單一樣式表
   色票／間距集中在 CSS 變數；美術席之後接手可只改這個區塊。
*/

:root {
  /* 色票（placeholder，等美術席正式版） */
  --color-bg: #faf9f7;
  --color-bg-elevated: #ffffff;
  --color-text: #1f2422;
  --color-text-muted: #5b625f;
  --color-accent: #2f6f5e;
  --color-accent-contrast: #ffffff;
  --color-border: #e2e0db;
  --color-link: #1c5c4b;

  /* 間距 */
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2.5rem;
  --space-5: 4rem;

  /* 排版 */
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang TC", "Heiti TC",
    "Microsoft JhengHei", "Noto Sans TC", "Segoe UI", sans-serif;
  --radius: 12px;
  --max-width: 720px;

  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #14181a;
    --color-bg-elevated: #1c2224;
    --color-text: #eef1ef;
    --color-text-muted: #a9b2ae;
    --color-accent: #6fd3b4;
    --color-accent-contrast: #0c1412;
    --color-border: #313a37;
    --color-link: #7fe0c2;
    color-scheme: dark;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-link);
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  padding: var(--space-1) var(--space-2);
  z-index: 100;
  border-radius: 0 0 var(--radius) 0;
}

.skip-link:focus {
  left: 0;
}

.site-header {
  padding: var(--space-2) var(--space-2) 0;
  text-align: center;
}

.brand-mark {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

main {
  display: block;
}

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-2);
}

section {
  padding: var(--space-4) 0;
}

section + section {
  border-top: 1px solid var(--color-border);
}

.hero {
  text-align: center;
  padding-top: var(--space-4);
}

.hero-avatar {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  margin: 0 auto var(--space-2);
  object-fit: cover;
  border: 1px solid var(--color-border);
}

.hero h1 {
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  margin: 0 0 var(--space-1);
}

.hero-position {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 46ch;
  margin: 0 auto var(--space-1);
}

.hero-sub {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-3);
}

.btn {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
}

.btn:hover,
.btn:focus-visible {
  filter: brightness(1.08);
}

h2 {
  font-size: 1.3rem;
  margin: 0 0 var(--space-2);
}

.about-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-2);
}

.about-list li {
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-2);
}

.post-grid {
  display: grid;
  gap: var(--space-2);
  grid-template-columns: 1fr;
}

.post-card {
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-2);
}

.post-card time {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.25rem;
}

.post-card h3 {
  font-size: 1.05rem;
  margin: 0 0 var(--space-1);
}

.post-card p {
  margin: 0 0 var(--space-1);
  color: var(--color-text);
}

.post-card .post-link {
  font-size: 0.9rem;
  font-weight: 600;
}

.follow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

.follow-list a {
  display: inline-block;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.6rem 1.1rem;
  text-decoration: none;
  font-weight: 600;
}

.follow-list a:hover,
.follow-list a:focus-visible {
  border-color: var(--color-accent);
}

footer {
  padding: var(--space-3) 0 var(--space-4);
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

footer p {
  margin: 0.35rem 0;
}

.not-found {
  text-align: center;
  padding: var(--space-5) var(--space-2);
}

@media (min-width: 768px) {
  .wrap {
    max-width: 760px;
  }

  .about-list {
    grid-template-columns: repeat(3, 1fr);
  }

  .post-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1280px) {
  .wrap {
    max-width: 900px;
  }

  .post-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    animation: none !important;
    scroll-behavior: auto !important;
  }
}