/* 3D Chess — dark theme, grid layout, panels, modals */

:root {
  --bg: #14161c;
  --panel: #1e222b;
  --panel-border: #2c313d;
  --text: #e8e6e1;
  --text-dim: #9aa0ab;
  --accent: #4da3ff;
  --good: #6ec55a;
  --warn: #e07a5f;
  --gold: #f0c75e;
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
}

/* ---- Header ---- */

#app-header {
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 14px;
  background: var(--panel);
  border-bottom: 1px solid var(--panel-border);
}

#brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 17px;
}

#brand-icon { font-size: 24px; color: var(--gold); }

#header-controls {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: nowrap;
  overflow-x: auto;
}

.hbtn {
  background: #262b36;
  color: var(--text);
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s;
}
.hbtn:hover:not(:disabled) { background: #323949; }
.hbtn:disabled { opacity: 0.45; cursor: default; }
.hbtn.primary { background: #2d6b4f; border-color: #3a8a66; }
.hbtn.primary:hover { background: #367f5e; }
.hbtn.accent { background: #4a4e14; border-color: #6b6f22; }
.hbtn.accent:hover { background: #5a5f1a; }
.hbtn.small { padding: 4px 8px; font-size: 12px; }
.hbtn.on { background: #5a3d7a; border-color: #7a56a3; }
.hbtn.on:hover { background: #6a4a90; }

.ctl {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-dim);
}
.ctl select {
  background: #262b36;
  color: var(--text);
  border: 1px solid var(--panel-border);
  border-radius: 6px;
  padding: 4px 6px;
  font-size: 13px;
}

.sep { width: 1px; height: 26px; background: var(--panel-border); margin: 0 4px; }

/* Learning-mode toggle */
.toggle { cursor: pointer; }
.toggle input { display: none; }
.toggle-track {
  width: 34px; height: 18px;
  background: #3a3f4d;
  border-radius: 9px;
  position: relative;
  transition: background 0.2s;
  display: inline-block;
}
.toggle input:checked + .toggle-track { background: var(--good); }
.toggle-knob {
  position: absolute;
  top: 2px; left: 2px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: #fff;
  transition: left 0.2s;
}
.toggle input:checked + .toggle-track .toggle-knob { left: 18px; }

/* ---- Layout ---- */

#layout {
  display: grid;
  grid-template-columns: 280px 1fr 300px;
  height: calc(100% - 52px);
}
body.learning-off #layout { grid-template-columns: 0 1fr 300px; }
body.learning-off #coach-panel { display: none; }

#coach-panel, #right-panel {
  background: var(--panel);
  border-right: 1px solid var(--panel-border);
  border-left: 1px solid var(--panel-border);
  display: flex;
  flex-direction: column;
  padding: 10px;
  gap: 10px;
  overflow: hidden;
}
#coach-panel { border-right: 1px solid var(--panel-border); }
#right-panel { border-left: 1px solid var(--panel-border); }

.panel-title {
  margin: 0 0 6px 0;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-dim);
}

.panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 6px;
}
.panel-head .panel-title { margin: 0; }

#coach-chat {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-right: 4px;
}

.coach-msg {
  padding: 8px 10px;
  border-radius: var(--radius);
  font-size: 13px;
  line-height: 1.45;
  background: #262b36;
  border-left: 3px solid var(--accent);
  animation: fade-in 0.25s ease;
}
.coach-msg.good { border-left-color: var(--good); }
.coach-msg.warn { border-left-color: var(--warn); background: #2e2424; }

@keyframes fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: none; }
}

/* ---- Viewport ---- */

#viewport {
  position: relative;
  min-width: 0;
}
#viewport canvas { display: block; }

#status-banner {
  position: absolute;
  top: 12px;
  left: 50%;
  transform: translateX(-50%);
  padding: 6px 18px;
  border-radius: 20px;
  background: rgba(20, 22, 28, 0.85);
  border: 1px solid var(--panel-border);
  font-size: 14px;
  font-weight: 600;
  pointer-events: none;
  z-index: 5;
}
#status-banner.warn { border-color: var(--warn); color: #f0a08a; }
#status-banner.good { border-color: var(--good); color: #a5e594; }
.banner-hidden { display: none; }

#thinking-indicator {
  position: absolute;
  bottom: 14px;
  right: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-dim);
  background: rgba(20, 22, 28, 0.85);
  padding: 6px 12px;
  border-radius: 20px;
  z-index: 5;
}
.hidden { display: none !important; }

.spinner {
  width: 12px; height: 12px;
  border: 2px solid var(--text-dim);
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---- Lesson card ---- */

#lesson-card {
  position: absolute;
  left: 14px;
  bottom: 14px;
  width: 340px;
  max-width: calc(100% - 28px);
  background: rgba(30, 34, 43, 0.95);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 12px;
  z-index: 6;
  box-shadow: 0 4px 20px rgba(0,0,0,0.4);
}

#lesson-title {
  font-weight: 700;
  font-size: 14px;
  margin-bottom: 6px;
  color: var(--gold);
}

#lesson-step-dots { display: flex; gap: 5px; margin-bottom: 8px; }
.dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #3a3f4d;
}
.dot.active { background: var(--accent); }
.dot.done { background: var(--good); }

#lesson-instruction {
  font-size: 13.5px;
  line-height: 1.5;
  min-height: 44px;
}
#lesson-instruction.success-text { color: #a5e594; }

#lesson-actions {
  display: flex;
  gap: 6px;
  margin-top: 10px;
  justify-content: flex-end;
}

.shake {
  animation: shake 0.35s ease;
}
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-7px); }
  50% { transform: translateX(7px); }
  75% { transform: translateX(-4px); }
}

/* ---- Right panel: captured + history ---- */

#captured-section { flex-shrink: 0; }

.captured-row {
  min-height: 26px;
  font-size: 20px;
  letter-spacing: 2px;
  padding: 2px 4px 8px;
  border-bottom: 1px solid var(--panel-border);
  margin-bottom: 6px;
  color: #cfcabe;
}
.captured-row .captured-glyph { opacity: 0.85; }

#history-section {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#move-history {
  flex: 1;
  overflow-y: auto;
  font-size: 13px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}

.history-row {
  display: grid;
  grid-template-columns: 34px 1fr 1fr;
  padding: 3px 4px;
  border-radius: 4px;
}
.history-row:nth-child(odd) { background: #22262f; }
.history-num { color: var(--text-dim); }

/* ---- Modals ---- */

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
}

.modal {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  padding: 22px;
  min-width: 320px;
  max-width: 90vw;
  max-height: 85vh;
  overflow-y: auto;
  box-shadow: 0 10px 40px rgba(0,0,0,0.5);
}
.modal.wide { width: 560px; }
.modal h3 { margin: 0 0 12px; font-size: 18px; }
.modal p { color: var(--text-dim); line-height: 1.5; }
.modal-head { display: flex; justify-content: space-between; align-items: center; }
.modal-actions { display: flex; gap: 10px; justify-content: center; margin-top: 16px; }

#promotion-choices { display: flex; gap: 10px; justify-content: center; }
#promotion-choices button {
  font-size: 42px;
  width: 70px; height: 70px;
  background: #262b36;
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  color: #f0ead9;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}
#promotion-choices button:hover {
  background: #36405a;
  transform: scale(1.08);
}

/* ---- Lesson browser ---- */

.lesson-cat {
  margin: 14px 0 8px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-dim);
}
.lesson-cat:first-child { margin-top: 0; }

.lesson-card {
  display: grid;
  grid-template-columns: 24px 1fr;
  grid-template-rows: auto auto;
  width: 100%;
  text-align: left;
  background: #262b36;
  border: 1px solid var(--panel-border);
  border-radius: 10px;
  padding: 10px 12px;
  margin-bottom: 8px;
  cursor: pointer;
  color: var(--text);
  transition: background 0.15s;
}
.lesson-card:hover { background: #323949; }
.lesson-check { grid-row: 1 / span 2; color: var(--good); font-weight: 700; }
.lesson-name { font-weight: 600; font-size: 14px; }
.lesson-sub {
  grid-column: 2;
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 2px;
}

/* ---- Scrollbars ---- */

::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #3a3f4d; border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #4a5060; }

/* ---- Small screens ---- */

@media (max-width: 1000px) {
  #layout { grid-template-columns: 220px 1fr 220px; }
  body.learning-off #layout { grid-template-columns: 0 1fr 220px; }
}
@media (max-width: 760px) {
  #layout { grid-template-columns: 0 1fr 180px; }
  #coach-panel { display: none; }
}