:root {
  color-scheme: light;
  --paper: oklch(94% 0.026 76);
  --paper-deep: oklch(89% 0.038 75);
  --ink: oklch(25% 0.038 52);
  --ink-soft: oklch(43% 0.032 58);
  --line: oklch(79% 0.035 69);
  --red: oklch(48% 0.145 32);
  --red-soft: oklch(92% 0.045 38);
  --moss: oklch(43% 0.064 125);
  --moss-soft: oklch(90% 0.043 121);
  --gold: oklch(72% 0.11 82);
  --surface: oklch(97% 0.016 80);
  --shadow: 0 20px 50px oklch(35% 0.05 60 / 0.16);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--paper-deep);
}

body {
  min-height: 100%;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, oklch(82% 0.08 42 / 0.22), transparent 42%),
    linear-gradient(180deg, var(--paper), var(--paper-deep));
  overflow-x: hidden;
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
}

.phone-shell {
  position: relative;
  width: min(100%, 480px);
  min-height: 100vh;
  margin: 0 auto;
  background: var(--paper);
  box-shadow: 0 0 0 1px oklch(70% 0.035 65 / 0.42);
  overflow: hidden;
}

.app-header {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  padding: calc(14px + env(safe-area-inset-top)) 18px 12px;
  background: oklch(94% 0.026 76 / 0.94);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 4px;
  color: var(--red);
  font-size: 0.72rem;
  font-weight: 760;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-block-start: 0;
}

h1 {
  margin: 0;
  font-size: 1.46rem;
  line-height: 1.18;
  letter-spacing: 0;
}

.icon-button,
.back-button {
  border: 1px solid var(--line);
  background: var(--surface);
  min-height: 42px;
  min-width: 42px;
  border-radius: 8px;
  box-shadow: 0 1px 0 oklch(100% 0 0 / 0.52) inset;
}

.icon-button {
  display: grid;
  place-items: center;
  padding: 0 12px;
  font-size: 1.25rem;
}

.back-button {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 0 12px;
  font-weight: 700;
}

.icon-button:focus-visible,
.back-button:focus-visible,
.search-box input:focus-visible,
.chip:focus-visible,
.position-tab:focus-visible,
.tactic-card:focus-visible {
  outline: 3px solid oklch(65% 0.12 72 / 0.66);
  outline-offset: 2px;
}

.app-main {
  padding: 14px 14px calc(24px + env(safe-area-inset-bottom));
}

.tools {
  position: sticky;
  top: calc(73px + env(safe-area-inset-top));
  z-index: 4;
  padding: 0 0 12px;
  background: linear-gradient(180deg, var(--paper) 72%, oklch(94% 0.026 76 / 0));
}

.search-box {
  display: grid;
  gap: 7px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.search-box span {
  color: var(--ink-soft);
  font-size: 0.76rem;
  font-weight: 760;
}

.search-box input {
  width: 100%;
  border: 0;
  padding: 0;
  color: var(--ink);
  background: transparent;
  font-size: 1rem;
  outline: 0;
}

.search-box input::placeholder {
  color: oklch(52% 0.03 58 / 0.72);
}

.chip-row {
  display: flex;
  gap: 8px;
  margin-top: 10px;
  padding-bottom: 2px;
  overflow-x: auto;
  scrollbar-width: none;
}

.chip-row::-webkit-scrollbar {
  display: none;
}

.chip {
  flex: 0 0 auto;
  min-height: 36px;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0 13px;
  color: var(--ink-soft);
  background: var(--surface);
  font-size: 0.88rem;
  font-weight: 700;
}

.chip[aria-selected="true"] {
  color: oklch(25% 0.045 39);
  background: var(--red-soft);
  border-color: oklch(67% 0.08 38);
}

.summary-strip {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 2px 2px 10px;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.summary-strip strong {
  color: var(--ink);
  font-size: 1.3rem;
}

.tactic-list {
  display: grid;
  gap: 10px;
}

.tactic-card {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 13px 12px;
  text-align: left;
  background: var(--surface);
  box-shadow: 0 1px 0 oklch(100% 0 0 / 0.5) inset;
}

.tactic-card:active {
  transform: translateY(1px);
}

.card-main {
  min-width: 0;
}

.card-kicker {
  display: flex;
  align-items: center;
  gap: 7px;
  margin-bottom: 7px;
}

.category-pill,
.level-pill {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  border-radius: 999px;
  padding: 0 8px;
  font-size: 0.72rem;
  font-weight: 780;
}

.category-pill {
  color: oklch(28% 0.052 126);
  background: var(--moss-soft);
}

.level-pill {
  color: oklch(32% 0.07 42);
  background: oklch(91% 0.051 62);
}

.tactic-card h2 {
  margin: 0 0 5px;
  font-size: 1.04rem;
  line-height: 1.28;
  letter-spacing: 0;
}

.tactic-card p {
  display: -webkit-box;
  margin: 0;
  overflow: hidden;
  color: var(--ink-soft);
  font-size: 0.88rem;
  line-height: 1.46;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.card-arrow {
  align-self: center;
  color: var(--red);
  font-size: 1.4rem;
}

.empty-state {
  padding: 22px 14px;
  border: 1px dashed var(--line);
  border-radius: 8px;
  color: var(--ink-soft);
  text-align: center;
  background: oklch(96% 0.018 80 / 0.72);
}

.detail-view {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  justify-items: center;
  background: oklch(18% 0.022 50 / 0.42);
  opacity: 0;
  pointer-events: none;
  transition: opacity 180ms ease-out;
}

.detail-view.is-open {
  opacity: 1;
  pointer-events: auto;
}

.detail-panel {
  width: min(100%, 480px);
  height: 100%;
  background: var(--paper);
  transform: translateY(16px);
  transition: transform 200ms ease-out;
  overflow-y: auto;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
}

.detail-view.is-open .detail-panel {
  transform: translateY(0);
}

.detail-top {
  position: sticky;
  top: 0;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: calc(12px + env(safe-area-inset-top)) 14px 10px;
  background: oklch(94% 0.026 76 / 0.95);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.detail-content {
  padding: 16px 14px calc(28px + env(safe-area-inset-bottom));
}

.detail-heading {
  margin-bottom: 14px;
}

.detail-heading h2 {
  margin: 10px 0 7px;
  font-size: 1.45rem;
  line-height: 1.18;
  letter-spacing: 0;
}

.detail-heading p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.55;
}

.board-card {
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.board-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
  color: var(--ink-soft);
  font-size: 0.82rem;
}

.board-meta strong {
  color: var(--red);
}

.position-tabs {
  display: flex;
  gap: 7px;
  margin-bottom: 8px;
  overflow-x: auto;
  scrollbar-width: none;
}

.position-tabs::-webkit-scrollbar {
  display: none;
}

.position-tab {
  flex: 0 0 auto;
  min-height: 32px;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0 11px;
  color: var(--ink-soft);
  background: oklch(95% 0.018 80);
  font-size: 0.78rem;
  font-weight: 760;
}

.position-tab[aria-selected="true"] {
  color: oklch(26% 0.052 38);
  background: var(--red-soft);
  border-color: oklch(67% 0.08 38);
}

.position-note {
  margin: 0 0 10px;
  color: var(--ink-soft);
  font-size: 0.82rem;
  line-height: 1.48;
}

.chess-board {
  position: relative;
  width: 100%;
  max-width: 100%;
  aspect-ratio: 100 / 116;
  border: 0;
  background:
    linear-gradient(oklch(82% 0.022 82 / 0.45) 1px, transparent 1px),
    linear-gradient(90deg, oklch(82% 0.022 82 / 0.45) 1px, transparent 1px),
    oklch(97% 0.017 86);
  background-size: 9% 5.2%, 9% 5.2%, auto;
  overflow: hidden;
}

.board-lines {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: visible;
}

.board-lines .grid-line {
  stroke: oklch(20% 0.012 70);
  stroke-width: 0.38;
}

.board-lines .outer-line {
  fill: transparent;
  stroke: oklch(18% 0.012 70);
  stroke-width: 1.1;
}

.board-lines .palace-line,
.board-lines .marker-line {
  stroke: oklch(18% 0.012 70);
  stroke-width: 0.38;
  fill: none;
}

.board-lines .palace-dot {
  fill: oklch(18% 0.012 70);
}

.board-lines .coord-label {
  fill: oklch(18% 0.012 70);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  font-size: 4.5px;
  font-weight: 660;
  text-anchor: middle;
  dominant-baseline: middle;
}

.board-lines .river-text {
  fill: oklch(18% 0.012 70);
  font-family: "Songti SC", "SimSun", "STSong", serif;
  font-size: 5.2px;
  font-weight: 900;
  text-anchor: middle;
  dominant-baseline: middle;
}

.piece {
  position: absolute;
  z-index: 1;
  transform: translate(-50%, -50%);
  display: grid;
  place-items: center;
  width: min(7.6%, 32px);
  aspect-ratio: 1;
  border: 2px solid currentColor;
  border-radius: 999px;
  background: oklch(96% 0.018 80);
  box-shadow:
    0 2px 0 oklch(62% 0.047 70 / 0.28),
    0 0 0 2px oklch(96% 0.018 80) inset;
  font-size: 0.95rem;
  font-weight: 900;
  line-height: 1;
}

.piece.red {
  color: var(--red);
}

.piece.black {
  color: oklch(28% 0.03 70);
}

.fact-list {
  display: grid;
  gap: 8px;
  margin: 14px 0;
}

.fact-list div,
.detail-section {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.fact-list div {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 10px;
  padding: 11px 12px;
}

dt {
  color: var(--red);
  font-size: 0.82rem;
  font-weight: 820;
}

dd {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.52;
}

.detail-section {
  margin-top: 10px;
  padding: 13px 13px 12px;
}

.detail-section h3 {
  margin: 0 0 9px;
  font-size: 0.94rem;
  line-height: 1.2;
}

.detail-section ul,
.detail-section ol {
  display: grid;
  gap: 7px;
  margin: 0;
  padding-left: 1.25rem;
  color: var(--ink-soft);
  line-height: 1.52;
}

.detail-section p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.56;
}

.caution {
  background: oklch(93% 0.043 64);
}

body.detail-open {
  overflow: hidden;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}