/* =========================================================
   kp-solver.css — ห้องฝึกเซียนโจทย์ (Problem Solving Dojo)
   ใช้คู่กับ kp.css และ kp-quest.css (ใช้แท็บ/กล่องคำพูด/หน้าต่างผลลัพธ์ร่วมกัน)
   ========================================================= */

.solver { max-width: 1180px; margin: 0 auto; padding: 16px 16px 40px; }
.solver [hidden], .kp-modal [hidden] { display: none !important; }

/* ---------- ระดับเซียน ---------- */
.s-rank { display: flex; align-items: center; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 10px; }
.s-rank .badge { font-size: 1.8rem; }
.s-rank b { font-family: var(--font-head); font-size: 1.1rem; }
.s-rank .meter { width: 160px; height: 10px; border-radius: 99px; background: var(--bg-soft); overflow: hidden; }
.s-rank .meter i { display: block; height: 100%; background: linear-gradient(90deg, var(--primary), var(--accent)); }

/* ---------- แถบขั้นตอน 3 ขั้น + นาฬิกา ---------- */
.s-head { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
.s-stepper { display: flex; gap: 6px; flex: 1 1 520px; }
.s-stepper div {
  flex: 1; display: flex; align-items: center; gap: 8px; padding: 8px 10px; border-radius: 14px;
  background: var(--surface); border: 2px solid var(--line); font: 500 .88rem var(--font-head); color: var(--muted); min-width: 0;
}
.s-stepper div span { flex: none; width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center; background: var(--bg-soft); font-weight: 600; }
.s-stepper div.now { border-color: var(--c); color: var(--ink); background: color-mix(in srgb, var(--c) 10%, var(--surface)); }
.s-stepper div.now span { background: color-mix(in srgb, var(--c) 22%, var(--surface)); color: color-mix(in srgb, var(--c) 45%, var(--ink)); box-shadow: inset 0 0 0 2px var(--c); }
.s-stepper div.done span { background: var(--good); color: var(--surface); }
.s-stepper div.done span::before { content: "✓"; }
.s-stepper div.done span b { display: none; }
@media (max-width: 640px) { .s-stepper div em { display: none; } .s-stepper div { justify-content: center; } }
.s-timer { font: 600 1.1rem var(--font-head); font-variant-numeric: tabular-nums; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 6px 12px; }
.s-timer.over { color: var(--warn); }

/* ---------- ผังหน้า ---------- */
.s-grid { display: grid; grid-template-columns: minmax(0, 1fr) 360px; grid-template-areas: "prob board" "pane board"; gap: 14px; align-items: start; }
.s-prob { grid-area: prob; }
.s-pane { grid-area: pane; }
.s-board { grid-area: board; position: sticky; top: 140px; }
@media (max-width: 960px) {
  .s-grid { grid-template-columns: 1fr; grid-template-areas: "prob" "board" "pane"; }
  .s-board { position: static; }
}

/* ---------- โจทย์ ---------- */
.s-text { font-size: 1.2rem; line-height: 2.05; }
.s-text .clue { cursor: pointer; border-radius: 6px; padding: 1px 2px; transition: background .2s; }
.s-text .clue:hover { background: var(--bg-soft); }
.s-text .clue.found { padding: 2px 6px; font-weight: 600; }
.s-text .clue.given, .s-text .clue.hidden { background: var(--good-soft); box-shadow: inset 0 -2px 0 var(--good); }
.s-text .clue.hidden { background: color-mix(in srgb, var(--st1) 18%, var(--surface)); box-shadow: inset 0 -2px 0 var(--st1); }
.s-text .clue.ask { background: var(--warn-soft); box-shadow: inset 0 -2px 0 var(--warn); }
.s-text .clue.cond { background: color-mix(in srgb, var(--st2) 16%, var(--surface)); box-shadow: inset 0 -2px 0 var(--st2); }
.s-text .clue.trap { text-decoration: line-through; color: var(--muted); background: var(--bg-soft); }
.s-text .clue.pulse { animation: s-pulse 1s ease 3; }
.s-text.reveal .clue:not(.found) { outline: 2px dashed var(--warn); }
@keyframes s-pulse { 50% { background: var(--accent); color: var(--on-vivid); } }
.s-found { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin-top: 10px; }
.s-legend { display: flex; gap: 10px; flex-wrap: wrap; font-size: .8rem; color: var(--muted); margin-top: 6px; }
.s-legend i { display: inline-block; width: 12px; height: 12px; border-radius: 3px; vertical-align: -1px; margin-right: 4px; }

/* ---------- กระดานตัวแปร ---------- */
.s-board h3 { display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px; }
.s-axis { border: 1px dashed var(--line); border-radius: 14px; padding: 8px 10px; margin-bottom: 8px; }
.s-axis > small { display: block; font: 500 .78rem var(--font-head); color: var(--muted); margin-bottom: 4px; }
.s-axis.bridge { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 6%, transparent); }
.s-chips { display: flex; flex-wrap: wrap; gap: 6px; min-height: 30px; }
.s-chip { display: inline-flex; align-items: center; gap: 4px; border-radius: 10px; padding: 3px 9px; font-size: .95rem; border: 1.5px solid var(--line); background: var(--surface); }
.s-chip.given { border-color: var(--good); background: var(--good-soft); }
.s-chip.hidden { border-color: var(--st1); background: color-mix(in srgb, var(--st1) 14%, var(--surface)); }
.s-chip.const { border-style: dashed; color: var(--muted); }
.s-chip.target { border-color: var(--warn); background: var(--warn-soft); font-weight: 600; }
.s-chip.derived { border-color: var(--st2); background: color-mix(in srgb, var(--st2) 14%, var(--surface)); }
.s-chip.unknown { border-style: dashed; color: var(--muted); }
.s-empty { color: var(--muted); font-size: .8rem; }
.s-trap { font-size: .85rem; color: var(--muted); }
.s-cond { font-size: .88rem; color: var(--st2-ink); margin-bottom: 4px; }

/* ---------- ขั้นที่ 2: การ์ดสมการ ---------- */
.s-eqs { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; }
.s-eq {
  appearance: none; text-align: left; font: inherit; color: var(--ink); cursor: pointer; background: var(--surface);
  border: 2px solid var(--line); border-radius: 16px; padding: 10px 12px; display: grid; gap: 6px; transition: border-color .2s, transform .15s;
}
.s-eq:hover { border-color: var(--primary); transform: translateY(-2px); }
.s-eq .tag { font: 500 .72rem var(--font-head); color: var(--muted); }
.s-eq.short { border-color: color-mix(in srgb, var(--accent) 55%, var(--line)); background: color-mix(in srgb, var(--accent) 6%, var(--surface)); }
.s-eq .tex { font-size: 1.12rem; text-align: center; padding: 4px 0; overflow-x: auto; }
.s-eq .vars { display: flex; gap: 4px; flex-wrap: wrap; justify-content: center; }
.s-eq .vars .s-chip { font-size: .8rem; padding: 1px 7px; }
.s-eq .st { font: 500 .8rem var(--font-head); text-align: center; border-radius: 8px; padding: 2px 6px; }
.s-eq .st.ok { background: var(--good-soft); color: var(--good); }
.s-eq .st.no { background: var(--bg-soft); color: var(--muted); }
.s-eq .st.warn { background: var(--warn-soft); color: var(--warn); }
.s-eq.used { opacity: .55; }
/* โหมดเซียน: ซ่อนตัวช่วยบอกสถานะตัวแปร */
.expert .s-eq .st { display: none; }
.expert .s-eq .vars .s-chip { border: 1.5px solid var(--line); background: var(--surface); color: var(--ink); font-weight: 400; }
.s-plan { counter-reset: p; display: grid; gap: 6px; margin: 12px 0 0; padding: 0; list-style: none; }
.s-plan li { counter-increment: p; display: flex; align-items: center; gap: 10px; background: var(--surface-2); border: 1px solid var(--line); border-radius: 12px; padding: 8px 12px; }
.s-plan li::before { content: counter(p); flex: none; width: 26px; height: 26px; border-radius: 50%; background: color-mix(in srgb, var(--st2) 22%, var(--surface)); color: var(--st2-ink); box-shadow: inset 0 0 0 2px var(--st2); display: grid; place-items: center; font: 600 .85rem var(--font-head); }
.s-plan li.goal::before { background: var(--warn); }
.s-tools { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; justify-content: space-between; margin-bottom: 10px; }

/* ---------- ขั้นที่ 3: คำนวณ ---------- */
.s-calc { display: grid; gap: 12px; }
.s-cstep { border-left: 5px solid var(--st3); }
.s-cstep.ok { border-left-color: var(--good); }
.s-cstep .line { background: var(--surface-2); border: 1px solid var(--line); border-radius: 12px; padding: 8px 12px; margin-top: 8px; overflow-x: auto; }
.s-cstep .line b { font-family: var(--font-head); font-size: .8rem; color: var(--muted); display: block; }
.s-cstep .tip { background: color-mix(in srgb, var(--accent) 12%, var(--surface)); border: 1px dashed var(--accent); border-radius: 12px; padding: 8px 12px; margin-top: 8px; }
.s-cstep .answer-row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; margin-top: 10px; }
.s-cstep .answer-row input { max-width: 170px; }

/* ---------- ลากวาง: จัดรูปสมการ + แทนค่า ---------- */
.s-dropzone { justify-content: center; border: 2px dashed var(--st2) !important; background: color-mix(in srgb, var(--st2) 6%, var(--surface)) !important; color: var(--muted); font-size: .9rem; min-height: 48px; }
.s-dropzone::before { display: none !important; }
.s-eq.dragging, .s-tile.dragging { opacity: .35; }
.drop-hover { outline: 3px solid var(--accent) !important; outline-offset: 2px; transform: scale(1.04); }
.dnd-ghost { position: fixed; z-index: 500; pointer-events: none; transform: translate(-50%, -50%) scale(1.08) rotate(-2deg); box-shadow: var(--shadow-lg); opacity: .95; max-width: 260px; }

.s-build { margin-top: 10px; border: 2px solid color-mix(in srgb, var(--st3) 40%, var(--line)); border-radius: 16px; padding: 10px 12px; background: color-mix(in srgb, var(--st3) 5%, var(--surface)); }
.s-phase { display: flex; gap: 6px; flex-wrap: wrap; }
.s-phase span { font: 500 .8rem var(--font-head); padding: 3px 10px; border-radius: 999px; background: var(--bg-soft); color: var(--muted); }
.s-phase span.on { background: color-mix(in srgb, var(--st3) 24%, var(--surface)); color: var(--st3-ink); box-shadow: inset 0 0 0 2px var(--st3); }
.s-instr { margin: 8px 0 6px; }
.s-eqbox { overflow-x: auto; padding: 10px 4px; }
.eq-line, .eq-row { display: inline-flex; align-items: center; gap: 6px; font-size: 1.2rem; }
.eq-frac { display: inline-flex; flex-direction: column; align-items: center; vertical-align: middle; }
.eq-num { padding: 0 4px 4px; border-bottom: 2px solid var(--ink); display: inline-flex; align-items: center; gap: 6px; }
.eq-den { padding: 4px 4px 0; display: inline-flex; align-items: center; gap: 6px; }
.eq-sqrt { display: inline-flex; align-items: stretch; }
.eq-rad { font-size: 1.6em; line-height: 1; margin-right: -2px; }
.eq-under { border-top: 2px solid var(--ink); padding: 4px 4px 0; display: inline-flex; align-items: center; gap: 6px; }
.eq-sup { display: inline-flex; align-items: flex-start; }
.eq-sup sup { font-size: max(12px, .7em); margin-left: 1px; }
.eq-slot {
  appearance: none; min-width: 52px; min-height: 44px; padding: 4px 8px; border-radius: 10px; cursor: pointer;
  border: 2px dashed var(--st3); background: var(--surface); color: var(--muted); font: 600 1.05rem var(--font-head);
  display: inline-grid; place-items: center; transition: transform .15s, background .2s, border-color .2s;
}
.eq-slot .ph { opacity: .45; }
.eq-slot.filled { border-style: solid; color: var(--ink); background: var(--warn-soft); }
.eq-slot.ok { border-color: var(--good); background: var(--good-soft); color: var(--ink); }
.eq-slot.bad { border-color: var(--bad); background: var(--bad-soft); }
.s-pool { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 4px; padding: 8px; border-radius: 12px; background: var(--surface-2); border: 1px dashed var(--line); min-height: 56px; }
.s-tile {
  appearance: none; border: 2px solid var(--st2); background: var(--surface); color: var(--ink); border-radius: 12px;
  min-width: 52px; min-height: 44px; padding: 4px 12px; font: 600 1.05rem var(--font-head); cursor: grab; user-select: none;
  box-shadow: 0 3px 0 color-mix(in srgb, var(--st2) 45%, transparent); transition: transform .12s;
}
.s-tile:hover { transform: translateY(-2px); }
.s-tile.val { border-color: var(--st4); box-shadow: 0 3px 0 color-mix(in srgb, var(--st4) 45%, transparent); font-size: .95rem; }
.s-tile.picked { outline: 3px solid var(--accent); outline-offset: 2px; }
.s-tile.gone { visibility: hidden; }
.s-combo { font: 700 1rem var(--font-head); color: var(--on-vivid); background: linear-gradient(90deg, #ff8a5b, #ec4899); border-radius: 999px; padding: 6px 14px; }
.s-combo.pop { animation: s-pop .35s ease; }
@keyframes s-pop { 50% { transform: scale(1.18); } }
@media (prefers-reduced-motion: reduce) { .s-combo.pop, .drop-hover { animation: none; transform: none; } }

/* ---------- ผลลัพธ์ ---------- */
.s-skills { display: grid; gap: 8px; margin: 12px 0; text-align: left; }
.s-skill { display: grid; grid-template-columns: 120px 1fr 48px; gap: 8px; align-items: center; font-size: .92rem; }
.s-skill .bar { height: 12px; border-radius: 9px; background: var(--bg-soft); overflow: hidden; }
.s-skill .bar i { display: block; height: 100%; border-radius: 9px; background: var(--c, var(--primary)); }
.s-skill b { text-align: right; font-family: var(--font-head); }
.s-model { text-align: left; border: 2px solid var(--st4); border-radius: 18px; padding: 12px 16px; background: color-mix(in srgb, var(--st4) 8%, var(--surface)); }
.s-model::before { content: "🥋 เฉลยแบบเซียน"; display: block; font: 600 .82rem var(--font-head); color: var(--st4-ink); margin-bottom: 6px; }
.s-model ol { margin: 0; padding-left: 20px; }
.s-model li { margin: 4px 0; }

/* ---------- เลือกตัวแปร ---------- */
.s-pick { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.s-pick button { appearance: none; border: 2px solid var(--line); background: var(--surface); color: var(--ink); border-radius: 14px; padding: 8px 10px; cursor: pointer; font: inherit; text-align: left; min-height: 56px; display: flex; gap: 10px; align-items: center; }
.s-pick button:hover { border-color: var(--primary); }
.s-pick button .sym { flex: none; min-width: 40px; text-align: center; font-size: 1.15rem; }
.s-pick button small { display: block; color: var(--muted); font-size: .76rem; line-height: 1.25; }
.s-pick button.wrong { border-color: var(--bad); background: var(--bad-soft); }
.s-pick button.trap { grid-column: 1 / -1; justify-content: center; border-style: dashed; min-height: 48px; }
@media (max-width: 420px) {
  .s-pick { gap: 6px; }
  .s-pick button { min-height: 48px; padding: 6px 8px; gap: 6px; font-size: .84rem; line-height: 1.25; }
  .s-pick button .sym { min-width: 26px; font-size: 1.05rem; }
  .s-pick button small { display: none; }
}

@media print {
  .s-head, .q-tabs, .s-tools, .q-result { display: none !important; }
}

/* ---------- สะพานจากขั้น 1 → 2: สรุปสิ่งที่มี + วิธีคิด 3 คำถาม ---------- */
.s-bridge .s-have { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin: 4px 0; }
.s-3q { margin-top: 12px; border: 2px solid color-mix(in srgb, var(--st2) 45%, var(--line)); background: color-mix(in srgb, var(--st2) 7%, var(--surface)); border-radius: 14px; padding: 10px 14px; }
.s-3q ol { margin: 6px 0 0; padding-left: 22px; }
.s-3q li { margin: 3px 0; }

/* ---------- ขั้น 2 โหมดไกด์: ต้นไม้ความคิด ---------- */
.s-tree { border: 2px dashed color-mix(in srgb, var(--st2) 50%, var(--line)); border-radius: 14px; padding: 10px 12px; background: var(--surface-2); }
.s-tree ul { list-style: none; margin: 6px 0 0; padding-left: 18px; border-left: 2px solid var(--line); }
.s-tree-root { padding-left: 0 !important; border-left: 0 !important; }
.s-tree li { margin: 6px 0; line-height: 1.9; }
.s-tree li.now > .s-chip { box-shadow: 0 0 0 3px color-mix(in srgb, var(--warn) 35%, transparent); }
.s-tree li.done > .s-chip { opacity: 1; }
.s-tree .s-need { color: var(--bad); font-weight: 600; }
.s-eq.has { border-color: var(--st2); box-shadow: 0 0 0 2px color-mix(in srgb, var(--st2) 25%, transparent); }
.s-eq.hint { animation: s-eqhint 1s ease 3; }
@keyframes s-eqhint { 50% { border-color: var(--accent); box-shadow: 0 0 0 5px color-mix(in srgb, var(--accent) 40%, transparent); } }

/* ---------- ขั้น 3: แผนที่เส้นทางคำนวณ ---------- */
.s-road { margin-bottom: 12px; }
.s-roadlist { list-style: none; margin: 8px 0 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.s-roadlist li { display: flex; align-items: center; gap: 8px; border: 2px solid var(--line); border-radius: 12px; padding: 6px 10px; background: var(--surface); }
.s-roadlist li > span { flex: none; width: 26px; height: 26px; border-radius: 50%; display: grid; place-items: center; font: 600 .85rem var(--font-head); background: var(--bg-soft); color: var(--ink); }
.s-roadlist li.now { border-color: var(--st3); background: color-mix(in srgb, var(--st3) 10%, var(--surface)); }
.s-roadlist li.now > span { background: color-mix(in srgb, var(--st3) 24%, var(--surface)); color: var(--st3-ink); box-shadow: inset 0 0 0 2px var(--st3); }
.s-roadlist li.done > span { background: var(--good); color: var(--surface); }
@media (prefers-reduced-motion: reduce) { .s-eq.hint { animation: none; outline: 3px solid var(--accent); } }