:root {
  --bg: #F6F7FB; --surface: #FFFFFF; --text: #1B1D29; --muted: #585D70;
  --line: #E3E5EE; --line-strong: #CBCFDD; --hover: #F1F2F8;
  --accent: #4F46E5; --accent-hover: #4338CA; --accent-ink: #4338CA;
  --accent-soft: #ECEEFF; --accent-line: #8F95F0; --ring: #4F46E5;
  --danger: #B42318; --danger-soft: #FDECEA;
  --shadow: 0 1px 2px rgba(20,22,40,.05), 0 6px 18px rgba(20,22,40,.05);
  --t0: #FFF5D1; --t1: #E3F3E8; --t2: #E6ECFF; --t3: #FDE8ED; --t4: #EFE7FA;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --bg: #0F1117; --surface: #171A23; --text: #ECEDF4; --muted: #A3A8BC;
  --line: #272B39; --line-strong: #3A3F54; --hover: #1F2330;
  --accent: #5B5FEF; --accent-hover: #6D70F5; --accent-ink: #B4B9FF;
  --accent-soft: #222543; --accent-line: #6469E8; --ring: #A5ABFF;
  --danger: #FDA29B; --danger-soft: #3A1D1D;
  --shadow: 0 1px 2px rgba(0,0,0,.3), 0 6px 18px rgba(0,0,0,.25);
  --t0: #2B2820; --t1: #1F2B25; --t2: #222842; --t3: #2E2128; --t4: #282339;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
body {
  margin: 0; min-height: 100vh; background: var(--bg); color: var(--text);
  font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
  font-size: 16px; line-height: 1.5;
}
:focus-visible { outline: 3px solid var(--ring); outline-offset: 2px; }
[hidden] { display: none !important; }

.wrap { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
@media (min-width: 720px) { .wrap { padding: 0 32px; } }

/* header */
.site-header { background: var(--surface); border-bottom: 1px solid var(--line); }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 68px; }
.header-actions { display: flex; align-items: center; gap: 4px; }
.brand {
  display: inline-flex; align-items: center; gap: 10px; font-weight: 650; font-size: 17px;
  letter-spacing: -.01em; text-decoration: none; color: var(--text); border-radius: 10px;
}
.logo {
  width: 32px; height: 32px; border-radius: 10px; background: var(--accent); color: #fff;
  display: inline-flex; align-items: center; justify-content: center;
}

/* buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 0 14px; border-radius: 12px; border: 1px solid transparent;
  background: transparent; color: var(--text); font: inherit; font-weight: 600; font-size: 15px;
  text-decoration: none; cursor: pointer;
}
.btn:hover { background: var(--hover); }
.btn-small { min-height: 40px; padding: 0 12px; font-size: 14px; color: var(--muted); }
.iconbtn {
  display: inline-flex; align-items: center; justify-content: center; width: 44px; height: 44px;
  border-radius: 12px; border: 1px solid transparent; background: transparent; color: var(--muted); cursor: pointer;
}
.iconbtn:hover { background: var(--hover); color: var(--text); }
.theme-dark-icon { display: none; }
:root[data-theme="dark"] .theme-dark-icon { display: block; }
:root[data-theme="dark"] .theme-light-icon { display: none; }

/* page intro */
.board-main { padding-top: 36px; padding-bottom: 72px; }
.intro { display: flex; flex-direction: column; gap: 4px; margin-bottom: 28px; }
.intro h1 { margin: 0; font-size: 28px; line-height: 1.2; letter-spacing: -.015em; }
.intro p { margin: 0; color: var(--muted); }

/* grid + cards */
.grid {
  list-style: none; margin: 0; padding: 0; display: grid; gap: 16px;
  grid-template-columns: repeat(1, minmax(0, 1fr));
}
@media (min-width: 640px) { .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; } }
@media (min-width: 960px) { .grid { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
@media (min-width: 1240px) { .grid { grid-template-columns: repeat(4, minmax(0, 1fr)); } }

.card {
  display: flex; flex-direction: column; gap: 10px; min-height: 176px; padding: 20px;
  border-radius: 12px; border: 1px solid var(--line); background: var(--surface);
  box-shadow: var(--shadow); color: var(--text);
}
.card.t0 { background: var(--t0); } .card.t1 { background: var(--t1); } .card.t2 { background: var(--t2); }
.card.t3 { background: var(--t3); } .card.t4 { background: var(--t4); }
.card.is-pinned { border: 1.5px solid var(--accent-line); box-shadow: 0 0 0 3px var(--accent-soft), var(--shadow); }
.card-title {
  margin: 0; font-size: 17px; line-height: 1.35; font-weight: 700; letter-spacing: -.005em;
  display: flex; align-items: flex-start; justify-content: space-between; gap: 10px;
  overflow-wrap: anywhere;
}
.card-body {
  margin: 0; font-size: 16px; line-height: 1.55; color: var(--text); flex: 1;
  white-space: pre-wrap; overflow-wrap: anywhere;
  display: -webkit-box; -webkit-box-orient: vertical; -webkit-line-clamp: 6; line-clamp: 6; overflow: hidden;
}
.card-date { font-size: 13px; color: var(--muted); margin-top: auto; }
.pinicon { flex: none; color: var(--accent-ink); margin-top: 2px; }

/* empty / error / loading */
.state {
  display: flex; flex-direction: column; align-items: center; text-align: center; gap: 8px; padding: 96px 20px;
}
.state h2 { margin: 12px 0 0; font-size: 20px; letter-spacing: -.01em; }
.state p { margin: 0; color: var(--muted); max-width: 320px; }
.state .btn { margin-top: 12px; border-color: var(--line-strong); }
.skeleton { min-height: 176px; border-radius: 12px; background: var(--hover); border: 1px solid var(--line); animation: pulse 1.2s ease-in-out infinite; }
@keyframes pulse { 50% { opacity: .5; } }
@media (prefers-reduced-motion: reduce) { .skeleton { animation: none; } }