/* ========== CSS Variables ========== */
:root {
  --bg: #e8f2fb;
  --blue-50:  #e3f1fd;
  --blue-100: #bbdefb;
  --blue-300: #64b5f6;
  --blue-500: #2196f3;
  --blue-700: #1565c0;
  --blue-900: #0d47a1;
  --text:       #1a1a2e;
  --text-muted: #546e7a;
  --text-light: #546e7a; /* 对比度 5.4:1 on white, WCAG AA 通过 */
  --glass-bg:   rgba(255,255,255,0.15);
  --glass-border: rgba(255,255,255,0.35);
  --glass-shadow: rgba(100,180,246,0.12);
  --card-bg:    rgba(255,255,255,0.35);
  --card-border: rgba(180,210,240,0.4);
  --card-hover-bg: rgba(255,255,255,0.52);
  --shadow-sm: 0 2px 16px rgba(100,180,246,0.06);
  --shadow-md: 0 6px 24px rgba(100,180,246,0.12);
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.3s cubic-bezier(0.4,0,0.2,1);
  --max-width: 960px;
  --nav-height: 64px;
}

* { margin:0; padding:0; box-sizing:border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: "Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ========== Full-screen Fixed Background ========== */
body::before {
  content: "";
  position: fixed; inset: 0; z-index:-2;
  background: url("../images/background.webp") center/cover no-repeat;
  filter: brightness(0.85);
}

body::after {
  content: "";
  position: fixed; inset: 0; z-index:-1;
  background: rgba(232,242,251,0.35);
  pointer-events: none;
}

/* ========== NAV ========== */
.nav {
  position: fixed; top: 0; left: 72px; right: 40px; z-index:1000;
  height: var(--nav-height);
  max-width: calc(var(--max-width) - 32px);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 0 0 var(--radius) var(--radius);
  box-shadow: var(--shadow-sm);
  display: flex; align-items: center;
}

.nav-inner {
  width: 100%;
  padding: 0 28px;
  display: flex; align-items: center; justify-content: space-between;
}

.nav-brand {
  font-size: 1.25rem; font-weight:700;
  color: var(--blue-700);
  letter-spacing: 0.02em;
  text-decoration: none;
}

.nav-links {
  display: flex; gap: 6px;
  list-style: none;
}

.nav-links a {
  display: inline-block; padding: 8px 18px;
  border-radius: 24px;
  font-size: 0.92rem; font-weight:500;
  color: var(--text-muted);
  text-decoration: none;
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--blue-700);
  background: rgba(33,150,243,0.10);
}

/* ========== Author Card ========== */
.author-section {
  position: relative; z-index: 1;
  padding: calc(var(--nav-height) + 140px) 40px 48px;
  display: flex; justify-content: flex-start;
}

.author-card {
  padding: 8px 4px;
  padding-left: 64px;
  text-align: left;
}

.author-name {
  font-size: 2.4rem; font-weight: 800;
  color: var(--blue-700);
  letter-spacing: 0.04em;
  line-height: 1.2;
}

.author-bio {
  margin-top: 10px;
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.65;
}

.author-social {
  margin-top: 16px;
  display: flex; gap: 20px;
}

.author-social a {
  color: var(--blue-500);
  text-decoration: none;
  font-size: 0.9rem; font-weight: 500;
  transition: var(--transition);
}

.author-social a:hover {
  color: var(--blue-700);
}

/* ========== Feed Section ========== */
.feed-section {
  position: relative; z-index:1;
  padding: 60px 40px 80px;
}

.feed-inner {
  max-width: var(--max-width);
  margin: 0 auto 0 0;
}

/* Section header with subtle branding */
.feed-header {
  margin-bottom: 28px;
  padding-left: 32px;
}

.feed-header-inner {
  display: flex; align-items: baseline; gap: 14px;
  padding: 14px 28px;
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.feed-header-inner h2 {
  font-size: 1.5rem; font-weight: 700;
  color: var(--blue-900);
  letter-spacing: 0.03em;
}

.feed-header-inner .feed-count {
  font-size: 0.85rem; color: var(--text-light);
  font-weight: 400;
}

/* ========== Feed Card ========== */
.feed-list {
  position: relative;
  display: flex; flex-direction: column;
  padding-left: 32px;
}

.feed-list::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(
    180deg,
    transparent 0%,
    rgba(100,180,246,0.22) 12%,
    rgba(100,180,246,0.22) 88%,
    transparent 100%
  );
}

.feed-item {
  position: relative;
  padding-bottom: 24px;
}

.feed-item:last-child { padding-bottom: 0; }

/* Timeline dot — 对齐到 .status-date 行的垂直中心 */
.feed-item::before {
  content: "";
  position: absolute;
  left: -40px; top: 26px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--blue-300);
  border: 3px solid var(--bg);
  box-shadow: 0 0 0 3px rgba(100,180,246,0.3);
  z-index: 2;
  transition: var(--transition);
}

/* ===== Status Card ===== */
.status-card {
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 22px 28px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.status-card:hover,
.status-card:focus-visible {
  background: var(--card-hover-bg);
  border-color: var(--blue-300);
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
}

.status-card:focus-visible {
  outline: 2px solid var(--blue-500);
  outline-offset: 2px;
}

.status-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--blue-700);
  margin-bottom: 6px;
}

.status-date {
  font-size: 0.75rem; color: var(--text-light);
  font-family: "JetBrains Mono","Fira Code","Consolas",monospace;
  margin-bottom: 8px;
  display: block;
}

.status-text {
  font-size: 0.95rem; color: var(--text);
  line-height: 1.75;
  margin: 0;
}

.status-text--muted { color: var(--text-light); }

/* ========== Load More Button ========== */
.load-more-wrap {
  text-align: center;
  margin-top: 32px;
}

.btn-loadmore {
  padding: 10px 44px;
  border: 1px solid rgba(33,150,243,0.3);
  border-radius: 24px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--blue-500);
  background: rgba(33,150,243,0.04);
  cursor: pointer;
  outline: none;
  transition: all 0.25s;
}

.btn-loadmore:hover,
.btn-loadmore:focus-visible {
  background: rgba(33,150,243,0.1);
  border-color: rgba(33,150,243,0.5);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-loadmore:disabled {
  opacity: 0.7;
  cursor: default;
  transform: none;
  box-shadow: none;
}

.hidden { display: none; }

/* ========== Footer Links ========== */
.footer-top {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 6px;
}

/* ========== Footer ========== */
.footer {
  position: relative; z-index:1;
  margin-top: auto;
  margin-left: 72px;
  max-width: calc(var(--max-width) - 32px);
  background: rgba(255,255,255,0.18);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-radius: var(--radius) var(--radius) 0 0;
}

.footer-inner {
  padding: 14px 32px;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.footer-links {
  display: flex; gap: 20px;
}

.footer-links a {
  color: var(--blue-700);
  text-decoration: none;
  transition: var(--transition);
}

.footer-links a:hover { color: var(--blue-700); }

/* ========== Back to Top ========== */
#back-to-top {
  position: fixed; bottom: 72px; right: 32px;
  z-index: 999;
  width: 44px; height: 44px;
  border-radius: 50%;
  background: var(--glass-bg);
  backdrop-filter: blur(14px) saturate(180%);
  -webkit-backdrop-filter: blur(14px) saturate(180%);
  border: 1px solid var(--glass-border);
  box-shadow: 0 4px 20px var(--glass-shadow);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: all var(--transition);
}

#back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#back-to-top:hover {
  background: rgba(255,255,255,0.5);
  box-shadow: 0 8px 30px rgba(100,180,246,0.25);
}

#back-to-top::before {
  content: "";
  width: 10px; height: 10px;
  border-left: 2px solid var(--blue-500);
  border-top: 2px solid var(--blue-500);
  transform: rotate(45deg) translate(2px,2px);
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
  /* Nav: full-width, flush top, bottom corners rounded */
  .nav {
    top: 0; left: 0; right: 0;
    border-radius: 0 0 var(--radius) var(--radius);
    box-shadow: none;
    background: rgba(232,242,251,0.2);
    border: none;
    border-bottom: 1px solid rgba(100,180,246,0.10);
  }

  .nav-inner { padding: 0 20px; }
  .nav-brand { font-size: 1.1rem; }
  .nav-links a { padding: 6px 12px; font-size: 0.82rem; }

  /* Background: prioritize right side */
  body::before { background-position: 70% center; }

  /* Author */
  .author-section { padding: calc(var(--nav-height) + 36px) 20px 32px; }
  .author-card { padding-left: 20px; }
  .author-name { font-size: 1.8rem; }
  .author-bio { font-size: 0.9rem; }
  .author-social { gap: 16px; }

  /* Feed — 仅留少量 padding-left 给时间线竖线 */
  .feed-section { padding: 36px 20px 56px; }
  .feed-header { padding-left: 12px; margin-bottom: 24px; }
  .feed-header-inner { padding: 12px 20px; }
  .feed-header-inner h2 { font-size: 1.25rem; }

  .feed-list { padding-left: 12px; }
  .feed-item { padding-bottom: 20px; }
  .feed-item::before { left: -20px; top: 20px; width: 10px; height: 10px; }

  .status-card { padding: 16px 20px; }
  .status-card:hover { transform: translateX(3px); }
  .status-text { font-size: 0.9rem; }

  /* Footer */
  .footer { margin-left: 0; max-width: none; }
  .footer-inner { padding: 14px 20px; }
  .footer-top { flex-direction: column; align-items: flex-start; gap: 8px; }
  .footer-links { gap: 14px; }

  /* Back to top */
  #back-to-top { bottom: 16px; right: 16px; width: 38px; height: 38px; }
}

@media (max-width: 480px) {
  .author-name { font-size: 1.5rem; }
  .author-bio { font-size: 0.85rem; }
  .feed-header-inner h2 { font-size: 1.1rem; }
  .feed-header-inner .feed-count { font-size: 0.78rem; }
  .status-card { padding: 14px 16px; }
  .status-title { font-size: 0.98rem; }
  .status-text { font-size: 0.85rem; }
  .btn-loadmore { padding: 8px 32px; font-size: 0.85rem; }
}