:root {
  --bg: #0f1216;
  --panel: #1a1f26;
  --panel-2: #222832;
  --text: #e7edf5;
  --muted: #9fb1c7;
  --accent: #5cb3ff;
  --warn: #ffb44c;
  --ok: #7cf49b;
  /* layout vars */
  --cell-size: 64px;
  --gap: 8px;
  --page-pad-x: 20px; /* main horizontal padding */
  --board-pad: 16px;  /* board inner padding */
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, "Helvetica Neue", Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: linear-gradient(180deg, #0c0f13, var(--bg));
  overflow-x: hidden; /* prevent accidental horizontal scroll */
}
header, footer { padding: 16px 20px; }
header h1 { margin: 0 0 8px; }
header p { color: var(--muted); margin: 0; }

main { display: grid; gap: 16px; padding: 16px var(--page-pad-x); }
 .sheet { display: grid; grid-template-columns: 1fr auto; gap: 16px; align-items: start; }
 .board {
  display: grid;
  grid-template-columns: var(--cell-size) repeat(5, var(--cell-size)) var(--cell-size);
  grid-template-rows: var(--cell-size) repeat(5, var(--cell-size));
  gap: var(--gap);
  padding: var(--board-pad);
  background: var(--panel);
  border-radius: 12px;
  box-shadow: 0 6px 24px rgba(0,0,0,0.35);
 }
 .col-top { grid-column: 2 / span 5; grid-row: 1; display: grid; grid-template-columns: repeat(5, var(--cell-size)); gap: var(--gap); }
 .row-right { grid-column: 7; grid-row: 2 / span 5; display: grid; grid-template-rows: repeat(5, var(--cell-size)); gap: var(--gap); }
 .grid { grid-column: 2 / span 5; grid-row: 2 / span 5; display: grid; grid-template-columns: repeat(5, var(--cell-size)); grid-template-rows: repeat(5, var(--cell-size)); gap: var(--gap); }
 .diag-left-top { grid-column: 1; grid-row: 1; }
 .diag-right-top { grid-column: 7; grid-row: 1; }
.cell {
  display: grid;
  place-items: center;
  background: var(--panel-2);
  border-radius: 8px;
  box-shadow: inset 0 2px 0 rgba(255,255,255,0.04), inset 0 -2px 0 rgba(0,0,0,0.3);
}
.cell.diag {
  background: linear-gradient(135deg, #233147, #1c2740);
  box-shadow: inset 0 2px 0 rgba(255,255,255,0.06), inset 0 -2px 0 rgba(0,0,0,0.38);
}
.cell input {
  width: 100%; height: 100%;
  text-align: center;
  font-size: 22px;
  color: var(--text);
  background: transparent;
  border: none; outline: none;
}
.cell input::placeholder { color: #5e6b7c; }
.cell input:focus { box-shadow: 0 0 0 2px var(--accent) inset; border-radius: 8px; }

.scores { padding: 16px; background: var(--panel); border-radius: 12px; box-shadow: 0 6px 24px rgba(0,0,0,0.35); min-width: 280px; }
.scores h2 { margin: 8px 0; font-size: 16px; color: var(--muted); }
.score-list { list-style: none; padding: 0; margin: 0 0 12px; display: grid; gap: 6px; }
.score-item { display: flex; justify-content: space-between; align-items: baseline; padding: 8px 10px; background: var(--panel-2); border-radius: 8px; }
.score-item .label { color: var(--muted); font-size: 12px; }
.score-item .combo { font-size: 12px; color: #b9c8dc; }
.score-item .points { font-weight: 600; }
.total { display: flex; justify-content: space-between; font-size: 18px; padding: 10px; background: #132036; border-radius: 8px; border: 1px solid #1f3354; }

.controls { display: flex; align-items: center; gap: 8px; }
button { cursor: pointer; padding: 10px 14px; border-radius: 8px; border: 1px solid #2b3a52; background: #173053; color: var(--text); font-weight: 600; }
button:hover { background: #1b3a61; }
.settings { padding: 10px 12px; background: var(--panel); border-radius: 8px; }
.settings summary { cursor: pointer; }
.settings-grid { display: grid; grid-template-columns: 1fr 80px; gap: 6px; }
.settings-grid label { color: var(--muted); font-size: 12px; align-self: center; }
.settings-grid input { width: 100%; padding: 6px 8px; border-radius: 6px; border: 1px solid #2b3a52; background: var(--panel-2); color: var(--text); }

.legend { padding: 12px; background: var(--panel); border-radius: 12px; }
.legend h2 { margin-top: 0; font-size: 16px; color: var(--muted); }
.legend ul { margin: 8px 0 0; color: #b9c8dc; }

/* Highlight lines with good combos */
.score-item.good .points { color: var(--ok); }
.score-item.warn .points { color: var(--warn); }

/* Inline row/col score boxes */
.score-box {
  display: grid;
  place-items: center;
  background: #182234;
  border: 1px solid #263753;
  color: var(--text);
  border-radius: 8px;
  font-weight: 700;
}
.score-box.diag {
  background: #1f3150;
  border-color: #32507d;
}

/* Responsive tweaks */
@media (max-width: 700px) {
  /* compute exact cell-size to fit viewport width without horizontal overflow */
  :root { 
    --cell-size: calc((100vw - (var(--page-pad-x) * 2) - (var(--board-pad) * 2) - (var(--gap) * 6)) / 7);
  }
  body { font-size: 16px; }
  .sheet { grid-template-columns: 1fr; }
  #side-scores { order: 2; }
  .board { order: 1; }
  .scores { min-width: unset; }
  .cell input { font-size: clamp(18px, 4.8vw, 22px); }
}
@media (max-width: 420px) {
  :root { 
    --cell-size: calc((100vw - (var(--page-pad-x) * 2) - (var(--board-pad) * 2) - (var(--gap) * 6)) / 7);
  }
  .cell input { font-size: clamp(16px, 5.5vw, 20px); }
}