/* ==========================================================================
   base.css - reset, typography, and the app shell (topbar / sidebar / main).
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--topbar-h) + 16px);
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: var(--fs-md);
  line-height: 1.65;
  font-feature-settings: 'cv11', 'ss03';
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
h1,
h2,
h3,
h4 {
  line-height: 1.2;
  letter-spacing: -0.015em;
  margin: 0 0 var(--sp-3);
  font-weight: 650;
  text-wrap: balance;
}
h1 {
  font-size: var(--fs-hero);
  letter-spacing: -0.03em;
  font-weight: 700;
}
h2 {
  font-size: var(--fs-2xl);
}
h3 {
  font-size: var(--fs-xl);
}
h4 {
  font-size: var(--fs-md);
}
p {
  margin: 0 0 var(--sp-4);
  text-wrap: pretty;
}
ul,
ol {
  margin: 0 0 var(--sp-4);
  padding-left: 1.25em;
}
li {
  margin-bottom: 0.35em;
}
a {
  color: var(--accent);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}
a:hover {
  color: var(--accent-hover);
  text-decoration-thickness: 2px;
}
code,
kbd,
pre,
.mono {
  font-family: var(--font-mono);
  font-size: 0.9em;
}
code {
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0.05em 0.35em;
}
strong {
  font-weight: 650;
}
small,
.small {
  font-size: var(--fs-sm);
}
.muted {
  color: var(--ink-3);
}
.lead {
  font-size: var(--fs-lg);
  color: var(--ink-2);
  max-width: 62ch;
}
hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: var(--sp-5) 0;
}
table {
  border-collapse: collapse;
  width: 100%;
}
button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}
img,
svg {
  max-width: 100%;
}

:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}
/* The page heading receives focus after navigation (for screen readers); it is not interactive, so no ring. */
#section-title:focus {
  outline: none;
}
:focus:not(:focus-visible) {
  outline: none;
}

.sr-only {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: fixed;
  left: 12px;
  top: -60px;
  z-index: 100;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  transition: top 0.15s var(--ease);
}
.skip-link:focus {
  top: 10px;
}

/* ------------------------------------------------------------------ topbar */
.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--topbar-h);
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: 0 var(--sp-4);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(14px);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  border-bottom: 1px solid var(--line);
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
  font-weight: 700;
  letter-spacing: -0.02em;
  font-size: var(--fs-lg);
}
.brand:hover {
  color: var(--ink);
}
.brand__mark {
  width: 30px;
  height: 30px;
  flex: none;
}
.brand__sub {
  font-weight: 500;
  color: var(--ink-3);
  font-size: var(--fs-sm);
  letter-spacing: 0;
  padding-left: 12px;
  margin-left: 2px;
  border-left: 1px solid var(--line-2);
}
.topbar__spacer {
  flex: 1;
}
.topbar__progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  height: 3px;
  background: var(--accent);
  width: 0;
  transition: width 0.4s var(--ease);
  border-radius: 0 3px 3px 0;
}
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 11px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--line);
  font-size: var(--fs-sm);
  color: var(--ink-2);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
.icon-btn {
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--ink-2);
  cursor: pointer;
  transition: background 0.15s var(--ease), color 0.15s var(--ease), border-color 0.15s var(--ease);
}
.icon-btn:hover {
  background: var(--surface-2);
  color: var(--ink);
}
.icon-btn[aria-pressed='true'] {
  background: var(--accent-soft);
  color: var(--accent);
  border-color: color-mix(in srgb, var(--accent) 30%, transparent);
}
.icon-btn svg {
  width: 20px;
  height: 20px;
}
.menu-btn {
  display: none;
}

/* ------------------------------------------------------------------ shell */
.shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  align-items: start;
  max-width: 1440px;
  margin: 0 auto;
}
.sidebar {
  position: sticky;
  top: var(--topbar-h);
  height: calc(100vh - var(--topbar-h));
  height: calc(100dvh - var(--topbar-h));
  overflow-y: auto;
  padding: var(--sp-5) var(--sp-4) var(--sp-5) var(--sp-5);
  border-right: 1px solid var(--line);
}
.sidebar__title {
  font-size: var(--fs-xs);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  font-weight: 650;
  margin: 0 0 var(--sp-3);
}
.nav {
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav li {
  margin: 0 0 2px;
}
.nav__link {
  display: grid;
  grid-template-columns: 28px 1fr auto;
  align-items: center;
  gap: 10px;
  padding: 9px 10px;
  border-radius: 10px;
  text-decoration: none;
  color: var(--ink-2);
  font-size: var(--fs-sm);
  line-height: 1.35;
  transition: background 0.15s var(--ease), color 0.15s var(--ease);
}
.nav__link:hover {
  background: var(--surface-2);
  color: var(--ink);
}
.nav__link[aria-current='page'] {
  background: var(--accent-soft);
  color: var(--ink);
  font-weight: 600;
  box-shadow: inset 3px 0 0 var(--accent);
}
.nav__num {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: var(--fs-xs);
  font-weight: 650;
  background: var(--surface-3);
  color: var(--ink-2);
  font-variant-numeric: tabular-nums;
}
.nav__link[aria-current='page'] .nav__num {
  background: var(--accent);
  color: var(--accent-ink);
}
.nav__link[data-done='true'] .nav__num {
  background: var(--good-bg);
  color: var(--good);
  border: 1px solid var(--good-line);
}
.nav__num svg {
  width: 14px;
  height: 14px;
}
.nav__min {
  font-size: var(--fs-xs);
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.timebox {
  margin-top: var(--sp-5);
  padding: var(--sp-4);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  font-size: var(--fs-sm);
}
.timebox strong {
  font-size: var(--fs-xl);
  letter-spacing: -0.02em;
  display: block;
  line-height: 1.2;
}
.timebox .bar {
  height: 6px;
  background: var(--track);
  border-radius: 999px;
  overflow: hidden;
  margin: 10px 0 8px;
}
.timebox .bar > span {
  display: block;
  height: 100%;
  background: var(--accent);
  border-radius: 999px;
  transition: width 0.4s var(--ease);
}

main {
  min-width: 0;
  padding: var(--sp-6) var(--sp-6) var(--sp-7);
  outline: none;
}
.view {
  max-width: var(--content-w);
  margin: 0 auto;
}
.view > * + * {
  margin-top: var(--sp-5);
}
.view.enter {
  animation: rise 0.35s var(--ease) both;
}
@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.pager {
  max-width: var(--content-w);
  margin: var(--sp-6) auto 0;
  display: flex;
  justify-content: space-between;
  gap: var(--sp-3);
  padding-top: var(--sp-5);
  border-top: 1px solid var(--line);
}

.scrim {
  display: none;
}

/* ------------------------------------------------------------------ responsive */
@media (max-width: 960px) {
  .shell {
    grid-template-columns: minmax(0, 1fr);
  }
  .menu-btn {
    display: inline-grid;
  }
  .sidebar {
    position: fixed;
    inset: var(--topbar-h) auto 0 0;
    width: min(340px, 88vw);
    height: auto;
    z-index: 45;
    background: var(--bg);
    transform: translateX(-102%);
    transition: transform 0.25s var(--ease);
    box-shadow: var(--shadow-md);
    visibility: hidden;
  }
  .sidebar[data-open='true'] {
    transform: none;
    visibility: visible;
  }
  .scrim[data-open='true'] {
    display: block;
    position: fixed;
    inset: var(--topbar-h) 0 0 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: 44;
  }
  main {
    padding: var(--sp-5) var(--sp-4) var(--sp-7);
  }
  .brand__sub {
    display: none;
  }
}
@media (max-width: 560px) {
  :root {
    --topbar-h: 56px;
  }
  .hide-sm {
    display: none !important;
  }
  .topbar {
    gap: 6px;
    padding: 0 10px;
  }
  .pager .btn {
    flex: 1;
    justify-content: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}

@media print {
  .topbar,
  .sidebar,
  .pager,
  .scrim {
    display: none !important;
  }
  .shell {
    display: block;
  }
  body {
    background: #fff;
    color: #000;
  }
}