.site-main--solver {
  --solver-surface: var(--panel);
  --solver-soft: color-mix(in srgb, var(--panel) 80%, var(--bg));
  --solver-muted: var(--article-body-color, #5e6e84);
  --isf: 1;
  --cell-digit-font-weight: 400;
  --chain-arrow-color-0: var(--user-color);
  --chain-arrow-color-1: var(--little-orange-2);
  --chain-arrow-color-2: var(--green-color);
  --chain-arrow-weak-color: var(--grid-icons-color);
  --chain-arrow-width: 2.5px;
  --chain-arrow-dash: 5 4;
  --chain-root-border-color: var(--title-color);
  --chain-root-border-width: 2.5px;
  --chain-note-on-bg: var(--green-color);
  --chain-note-off-bg: var(--little-orange-1);
  display: block;
  align-items: initial;
  justify-content: initial;
  padding: 0;
}

.solver-shell { max-width: var(--article-container); margin: 0 auto; padding: 0 20px 90px; }
.solver-eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.solver-hero { max-width: var(--article-prose-width); margin-bottom: 30px; }
.solver-hero h1 {
  margin: 0 0 16px;
  font-size: var(--article-h1-size);
  font-weight: var(--article-h1-weight);
  line-height: var(--article-h1-line);
  letter-spacing: var(--article-h1-spacing);
}
.solver-hero > p:last-child {
  margin: 0;
  max-width: 720px;
  color: var(--article-body-color);
  font-size: var(--article-lead-size);
  line-height: var(--article-lead-line);
}

.solver-mode-row {
  display: flex;
  align-items: stretch;
  gap: 12px;
  max-width: 790px;
  margin-bottom: 24px;
}
.solver-paste-top { flex: 0 0 auto; min-height: 60px; padding-inline: 22px; color: var(--accent); }

.solver-summary {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  overflow: hidden;
  margin-bottom: 16px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: var(--border);
}
.solver-summary[hidden], .solver-progress[hidden] { display: none; }
.solver-summary > div { min-width: 0; padding: 16px 18px; background: var(--solver-surface); }
.solver-summary span { display: block; margin-bottom: 4px; color: var(--solver-muted); font-size: 12px; text-transform: uppercase; letter-spacing: .06em; }
.solver-summary strong { display: block; overflow: hidden; font-size: 16px; font-weight: 600; text-overflow: ellipsis; white-space: nowrap; }

.solver-progress { margin: 0 0 22px; padding-top: 26px; }
.solver-progress__head { display: flex; justify-content: space-between; margin-bottom: 8px; color: var(--solver-muted); font-size: 13px; }
.solver-progress__row { display: flex; align-items: center; gap: 10px; }
.solver-progress__track { display: flex; flex: 1 1 auto; align-items: flex-end; gap: 2px; height: 9px; position: relative; }
.solver-progress__nav {
  display: grid;
  flex: 0 0 32px;
  place-items: center;
  width: 32px;
  height: 32px;
  padding: 0 0 3px;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--accent);
  background: var(--panel);
  font-family: inherit;
  font-size: 20px;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
}
.solver-progress__nav:hover:not(:disabled) { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--panel)); }
.solver-progress__nav:disabled { opacity: .35; cursor: default; }
.solver-progress__track button {
  flex: 1 1 0;
  min-width: 2px;
  height: 9px;
  padding: 0;
  border: 0;
  border-radius: 4px;
  background: color-mix(in srgb, var(--step-color, var(--border)) 34%, var(--border));
  cursor: pointer;
  transition: height 420ms cubic-bezier(0.22, 1, 0.36, 1);
}
.solver-progress__track button.is-complete { background: var(--step-color, var(--green-color)); }
.solver-progress__track button.is-current {
  background: var(--step-color, var(--accent));
  height: 16px;
  position: relative;
  z-index: 2;
}
.solver-progress__track button.is-search { background: var(--little-orange-1); }

.solver-workspace { display: grid; grid-template-columns: minmax(0, 1.45fr) minmax(320px, .9fr); gap: 24px; align-items: stretch; }
.solver-side-col { position: relative; min-width: 0; }
.solver-board-card, .solver-coach {
  border: 1px solid var(--border);
  border-radius: 24px;
  background: transparent;
  box-shadow: none;
}
.solver-board-card { display: flex; flex-direction: column; align-items: center; padding: 22px; }
.solver-board-head { display: flex; align-items: center; justify-content: space-between; width: 100%; margin-bottom: 17px; }
.solver-board-head p { margin: 0 0 3px; color: var(--solver-muted); font-size: 12px; font-weight: 600; text-transform: uppercase; letter-spacing: .08em; }
.solver-board-head h2 { margin: 0; font-size: 21px; font-weight: 600; }
.solver-entry-head { width: 100%; margin: 0 0 17px; }
.solver-entry-head p { margin: 0 0 3px; color: var(--solver-muted); font-size: 12px; font-weight: 600; text-transform: uppercase; letter-spacing: .08em; }
.solver-coach .solver-entry-head h2 { margin: 0; font-size: 21px; font-weight: 600; line-height: normal; letter-spacing: normal; }
.solver-link-button { border: 0; background: transparent; color: var(--accent); font: inherit; font-weight: 600; cursor: pointer; }
.solver-grid-wrap { position: relative; width: var(--grid-size); height: var(--grid-size); max-width: 100%; }
#solverGrid { width: var(--grid-size); height: var(--grid-size); max-width: 100%; }
#solverGrid .sudoku-grid__canvas { border-radius: var(--grid-radius, 8px); }
#solverGrid::before {
  border-radius: var(--grid-radius, 8px);
  background: none;
  box-shadow: inset 0 0 0 var(--grid-line-thick) var(--grid-line-thick-color);
}
.solver-board-card.is-solving .sudoku-grid__canvas { cursor: default !important; }

.solver-loading {
  position: absolute;
  inset: 0;
  z-index: 7;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 35px;
  text-align: center;
  color: var(--text);
  background: color-mix(in srgb, var(--panel) 91%, transparent);
  backdrop-filter: blur(5px);
}
.solver-loading[hidden] { display: none; }
.solver-loading > span:last-child { max-width: 330px; color: var(--solver-muted); line-height: 1.5; }
.solver-spinner { width: 34px; height: 34px; border: 3px solid var(--border); border-top-color: var(--accent); border-radius: 50%; animation: solver-spin .8s linear infinite; }
@keyframes solver-spin { to { transform: rotate(360deg); } }

.solver-keypad-side-mount { display: contents; }
.solver-keypad { display: grid; grid-template-columns: repeat(9, 1fr); gap: 7px; width: var(--grid-size); max-width: 100%; margin-top: 17px; }
.solver-keypad[hidden] { display: none; }
.solver-keypad button {
  aspect-ratio: 1;
  min-width: 0;
  border: 1px solid var(--tone-2);
  border-radius: 10px;
  color: var(--puzzle-color);
  background: var(--tone-1);
  font: inherit;
  font-size: clamp(19px, 2.4vw, 26px);
  font-weight: 400;
  cursor: pointer;
  transition: background-color 120ms ease, transform 80ms ease, filter 120ms ease;
}
[data-orientation='portrait'] .solver-keypad button { aspect-ratio: 2 / 3; }
.solver-keypad button:hover { background: var(--tone-0); }
.solver-keypad.is-pencil button { background: var(--deep-color); border-color: transparent; color: var(--puzzle-color); }
.solver-keypad.is-pencil button:hover { filter: brightness(1.06); }
.solver-keypad button:not(:disabled):active { transform: scale(0.94); }
/* Navy theme: darken pencil buttons so pen/pencil are distinguishable. */
[data-theme-index='5'] .solver-keypad.is-pencil button { background: color-mix(in srgb, var(--deep-color) 50%, var(--tone-11)); }

.solver-button { min-height: 46px; padding: 10px 16px; border-radius: 12px; font: inherit; font-weight: 600; cursor: pointer; }
.solver-button:disabled { opacity: .42; cursor: default; }
.solver-button--primary { border: 1px solid var(--accent); color: var(--tone-minus-one, #fff); background: var(--accent); }
.solver-button--quiet { border: 1px solid var(--tone-2); color: var(--puzzle-color); background: var(--tone-1); }

.solver-coach { position: absolute; inset: 0; box-sizing: border-box; padding: 22px; overflow: hidden; }
.solver-coach h2 { margin: 0 0 11px; font-size: clamp(23px, 2.5vw, 30px); line-height: 1.17; letter-spacing: -.025em; }
.solver-coach__lead { margin: 0; color: var(--solver-muted); font-size: 16px; line-height: 1.6; }
.solver-entry-tools { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin: 24px 0; }
.solver-entry-tools button {
  display: grid;
  min-width: 0;
  min-height: 48px;
  padding: 8px;
  place-items: center;
  border: 1px solid var(--tone-2);
  border-radius: 13px;
  background: var(--tone-1);
  color: var(--puzzle-color);
  cursor: pointer;
  transition: background-color 120ms ease, transform 80ms ease, filter 120ms ease;
}
.solver-entry-tools button:hover:not(:disabled):not(.is-active) { background: var(--tone-0); }
.solver-entry-tools button.is-active { background: var(--deep-color); border: 2px solid var(--puzzle-color); }
.solver-entry-tools button.is-active:hover { filter: brightness(1.06); }
.solver-entry-tools button:not(:disabled):active { transform: scale(0.94); }
.solver-entry-tools button:disabled { opacity: .35; cursor: default; }
.solver-entry-tools .solver-entry-tool-icon { width: 22px; height: 22px; color: var(--puzzle-color); }
.solver-entry-actions { margin-top: 12px; }
.solver-entry-actions .solver-button { width: 100%; min-height: 52px; }

.solver-step-head { display: flex; align-items: start; justify-content: space-between; gap: 10px; }
.solver-step-head > span { color: var(--solver-muted); font-size: 13px; white-space: nowrap; }
.solver-hint-nav { display: flex; align-items: center; justify-content: flex-end; gap: 10px; margin: 18px 0; }
.solver-hint-nav[hidden] { display: none; }
.solver-hint-nav span { min-width: 54px; color: var(--solver-muted); font-size: 13px; text-align: center; }
.solver-hint-nav button { display: grid; place-items: center; width: 32px; height: 32px; padding: 0 0 3px; border: 1px solid var(--border); border-radius: 10px; color: var(--accent); background: var(--panel); font-family: inherit; font-size: 20px; font-weight: 600; line-height: 1; cursor: pointer; }
.solver-hint-nav button:hover:not(:disabled) { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--panel)); }
.solver-hint-nav button:disabled { opacity: .35; cursor: default; }
.solver-result { margin: 0 0 20px; padding: 15px; border-left: 3px solid var(--accent); border-radius: 4px 12px 12px 4px; background: color-mix(in srgb, var(--accent) 8%, transparent); }
.solver-result[hidden] { display: none; }
.solver-result span { color: var(--accent); font-size: 11px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.solver-result p { margin: 5px 0 0; line-height: 1.5; }

.solver-description { border-top: 1px solid var(--border); }
.solver-technique-links {
  list-style: none;
  margin: 0 0 var(--article-para-margin);
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px 24px;
}
.solver-technique-links li {
  font-size: var(--article-body-size);
  line-height: var(--article-body-line);
  color: var(--article-body-color);
}
.solver-technique-links a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.solver-technique-links a:hover { text-decoration: underline; }
.solver-description .site-description__inner > p:last-child a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}
@media (max-width: 560px) {
  .solver-technique-links { grid-template-columns: 1fr; }
}
.solver-dialog { width: min(560px, calc(100% - 28px)); padding: 0; border: 1px solid var(--border); border-radius: 20px; color: var(--text); background: var(--panel); box-shadow: 0 28px 90px rgba(0,0,0,.24); }
.solver-dialog::backdrop { background: rgba(8, 14, 28, .48); backdrop-filter: blur(3px); }
.solver-dialog form { padding: 24px; }
.solver-dialog__head { display: flex; align-items: center; justify-content: space-between; }
.solver-dialog h2 { margin: 0; font-size: 24px; }
.solver-dialog__head button { border: 0; color: var(--solver-muted); background: none; font-size: 28px; cursor: pointer; }
.solver-dialog p { color: var(--solver-muted); line-height: 1.5; }
.solver-dialog textarea { width: 100%; resize: vertical; padding: 13px; border: 1px solid var(--border); border-radius: 12px; color: var(--text); background: var(--solver-soft); font: 16px/1.5 monospace; user-select: text; }
.solver-dialog .solver-dialog__error { color: var(--wrong-color); }
.solver-dialog__actions { display: flex; justify-content: flex-end; gap: 9px; margin-top: 18px; }

@media (max-width: 900px) {
  .solver-shell { padding-inline: 14px; }
  .solver-workspace { grid-template-columns: 1fr; }
  .solver-coach { position: static; inset: auto; overflow: visible; height: auto; }
  .solver-coach__inner { zoom: 1 !important; }
  .solver-coach__inner[style] { zoom: 1 !important; }
  .solver-summary { grid-template-columns: repeat(2, 1fr); }
}

[data-orientation='landscape'] .solver-keypad {
  grid-template-columns: repeat(3, 1fr);
  width: min(100%, 300px);
  margin: 24px auto;
  gap: 9px;
}
[data-orientation='landscape'] .solver-keypad button { border-radius: 14px; font-size: clamp(24px, 4vh, 34px); }
[data-orientation='landscape'] .solver-keypad-side-mount:not(:empty) { display: block; }

@media (max-width: 980px) and (orientation: landscape) {
  .solver-workspace { grid-template-columns: minmax(0, 1.25fr) minmax(270px, .85fr); gap: 14px; }
  .solver-coach { padding: 22px; }
}

@media (max-width: 560px) {
  .solver-shell { padding-top: 28px; }
  .solver-hero { margin-bottom: 22px; }
  .solver-mode-row { flex-direction: column; gap: 8px; }
  .solver-paste-top { width: 100%; min-height: 46px; padding-inline: 13px; }
  .solver-board-card { margin-inline: -14px; padding: 8px; border-inline: 0; border-radius: 0; }
  .solver-summary > div { padding: 13px; }
  .solver-summary strong { font-size: 14px; }
  .solver-keypad { gap: 3px; }
  .solver-keypad button { border-radius: 7px; }
  .solver-coach { padding: 21px 18px; border-radius: 18px; }
}

@media (prefers-reduced-motion: reduce) {
  .solver-spinner { animation: none; }
}