/* DataQuest — Module Styles
   --cc  : class accent color
   --cc-d: class accent dim
   --cc-g: class accent glow
*/

/* ── NAV ── */
.nav {
  position: sticky; top: 0; z-index: 100;
  height: var(--nav-h);
  display: flex; align-items: center;
  padding: 0 24px; gap: 12px;
  background: rgba(5,5,7,.85);
  backdrop-filter: blur(20px) saturate(1.4);
  border-bottom: 1px solid var(--b-subtle);
}
.nav-logo {
  display: flex; align-items: center; gap: 9px;
  text-decoration: none; color: var(--t-1);
  font-weight: 700; font-size: .95rem; letter-spacing: -.01em;
  flex-shrink: 0;
}
.nav-logo-mark {
  width: 28px; height: 28px; border-radius: 7px;
  background: var(--cc, var(--ex));
  display: flex; align-items: center; justify-content: center;
  font-size: .8rem; color: #fff; font-weight: 800;
  flex-shrink: 0;
}
.nav-logo-dot { color: var(--cc, var(--ex)); }
.nav-divider { width: 1px; height: 20px; background: var(--b-subtle); margin: 0 4px; }
.nav-module {
  font-size: .78rem; font-weight: 500;
  color: var(--t-3); letter-spacing: 0;
}

.nav-right { display: flex; align-items: center; gap: 8px; margin-left: auto; }

.nav-score {
  display: flex; align-items: center; gap: 7px;
  font-family: var(--f-mono); font-size: .72rem;
  color: var(--cc, var(--ex));
  background: var(--cc-d, var(--ex-dim));
  border: 1px solid var(--cc-g, var(--ex-glow));
  border-radius: 20px; padding: 5px 13px;
}
.nav-score-dot {
  width: 5px; height: 5px; border-radius: 50%;
  background: var(--cc, var(--ex));
  animation: pulse 2s infinite;
}

.nav-btn {
  display: flex; align-items: center; gap: 6px;
  font-size: .75rem; font-weight: 500;
  color: var(--t-3); border: 1px solid var(--b-subtle);
  border-radius: var(--r-md); padding: 5px 12px;
  transition: all var(--fast);
  text-decoration: none;
}
.nav-btn:hover { color: var(--t-1); border-color: var(--b-default); }
.nav-btn svg { width: 12px; height: 12px; fill: currentColor; flex-shrink: 0; }
.nav-btn-back:hover { color: var(--cc, var(--ex)); border-color: var(--cc-g, var(--ex-glow)); }
.nav-btn-reset:hover { color: var(--err); border-color: var(--err); background: var(--err-d); }

/* ── PROGRESS ── */
.prog {
  height: 2px; background: var(--b-subtle);
  position: sticky; top: var(--nav-h); z-index: 99;
}
.prog-fill {
  height: 100%;
  background: var(--cc, var(--ex));
  transition: width var(--slow) var(--ease);
}

/* ── LAYOUT ── */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: calc(100vh - var(--nav-h) - 2px);
}

/* ── SIDEBAR ── */
.sidebar {
  border-right: 1px solid var(--b-subtle);
  background: var(--bg-1);
  overflow-y: auto;
  position: sticky; top: calc(var(--nav-h) + 2px);
  max-height: calc(100vh - var(--nav-h) - 2px);
}

/* Module info block */
.sb-info {
  padding: 20px 18px 16px;
  border-bottom: 1px solid var(--b-subtle);
}
.sb-info-label {
  font-size: .65rem; font-weight: 600;
  letter-spacing: .1em; text-transform: uppercase;
  color: var(--t-3); margin-bottom: 6px;
}
.sb-info-name {
  font-size: .95rem; font-weight: 700; color: var(--t-1);
  margin-bottom: 14px;
}
/* Progress bar */
.sb-prog-track {
  height: 3px; background: var(--b-subtle);
  border-radius: 2px; overflow: hidden; margin-bottom: 6px;
}
.sb-prog-fill {
  height: 100%; background: var(--cc, var(--ex));
  border-radius: 2px; transition: width var(--slow) var(--ease);
}
.sb-prog-label {
  font-family: var(--f-mono); font-size: .62rem; color: var(--t-3);
  display: flex; justify-content: space-between;
}

/* Section groups */
.sb-group { padding: 8px 0 2px; }
.sb-group-title {
  padding: 0 16px 6px;
  font-size: .62rem; font-weight: 600;
  letter-spacing: .1em; text-transform: uppercase; color: var(--t-3);
  display: flex; align-items: center; justify-content: space-between;
}
.sb-group-count {
  font-family: var(--f-mono); font-size: .58rem;
  color: var(--t-4); background: var(--bg-2);
  border: 1px solid var(--b-subtle);
  padding: 1px 6px; border-radius: 10px;
}
.sb-sep { height: 1px; background: var(--b-subtle); margin: 4px 0; }

/* Item */
.sb-item {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 16px; cursor: pointer;
  border-left: 2px solid transparent;
  transition: background var(--fast), border-color var(--fast);
}
.sb-item:hover { background: rgba(255,255,255,.03); }
.sb-item.active {
  border-left-color: var(--cc, var(--ex));
  background: var(--cc-d, var(--ex-dim));
}
.sb-inner { flex: 1; min-width: 0; }
.sb-meta { display: flex; align-items: center; gap: 6px; margin-bottom: 2px; }
.sb-num { font-family: var(--f-mono); font-size: .58rem; color: var(--t-4); }
.sb-name { font-size: .8rem; font-weight: 500; color: var(--t-2); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.sb-item.active .sb-name { color: var(--t-1); }
.sb-check {
  font-size: .65rem; color: var(--cc, var(--ex));
  opacity: 0; transform: scale(.5);
  transition: all var(--med) var(--ease); flex-shrink: 0;
}
.sb-item.done .sb-check { opacity: 1; transform: scale(1); }

/* Diff pills */
.dpill {
  font-family: var(--f-mono); font-size: .55rem; font-weight: 600;
  padding: 1px 6px; border-radius: 4px; letter-spacing: .02em;
}
.dpill-easy   { color: var(--ok);   background: var(--ok-d); }
.dpill-medium { color: var(--warn); background: var(--warn-d); }
.dpill-hard   { color: var(--err);  background: var(--err-d); }

/* ── MAIN ── */
.main {
  padding: 32px 40px;
  display: flex; flex-direction: column; gap: 24px;
  animation: fadeIn var(--med) var(--ease);
}

/* Complete banner */
.done-banner {
  display: none; align-items: center; gap: 16px;
  padding: 16px 22px;
  background: var(--ok-d);
  border: 1px solid rgba(52,211,153,.2);
  border-radius: var(--r-lg);
  animation: fadeUp var(--med) var(--ease);
}
.done-banner.show { display: flex; }
.done-banner-title { font-size: .88rem; font-weight: 600; color: var(--ok); }
.done-banner-sub   { font-size: .78rem; color: var(--t-3); margin-top: 1px; }

/* Challenge header */
.ch-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 20px; }
.ch-breadcrumb {
  font-family: var(--f-mono); font-size: .65rem; color: var(--t-3);
  margin-bottom: 8px; display: flex; align-items: center; gap: 8px;
}
.ch-breadcrumb-sep { opacity: .4; }
.ch-title {
  font-size: clamp(1.4rem,2.5vw,1.9rem);
  font-weight: 800; letter-spacing: -.03em;
  line-height: 1.15; color: var(--t-1);
}
.ch-title-accent { color: var(--cc, var(--ex)); }
.ch-tags { display: flex; gap: 6px; margin-top: 10px; flex-wrap: wrap; }
.tag {
  font-family: var(--f-mono); font-size: .62rem; font-weight: 500;
  padding: 3px 9px; border-radius: var(--r-sm);
  border: 1px solid;
}
.tag-easy   { color: var(--ok);   border-color: rgba(52,211,153,.25);  background: var(--ok-d); }
.tag-medium { color: var(--warn); border-color: rgba(251,191,36,.25);  background: var(--warn-d); }
.tag-hard   { color: var(--err);  border-color: rgba(248,113,113,.25); background: var(--err-d); }
.tag-cat    { color: var(--cc, var(--ex)); border-color: var(--cc-g, var(--ex-glow)); background: var(--cc-d, var(--ex-dim)); }

.pts-badge {
  flex-shrink: 0;
  font-family: var(--f-mono); font-size: .75rem; font-weight: 600;
  color: var(--bg-base); background: var(--cc, var(--ex));
  border-radius: var(--r-md); padding: 7px 16px; white-space: nowrap;
}

/* Description */
.ch-desc {
  font-size: .93rem; line-height: 1.75; color: var(--t-2);
  padding: 16px 20px;
  background: var(--bg-1);
  border: 1px solid var(--b-subtle);
  border-radius: var(--r-md);
}
.ch-desc code {
  font-family: var(--f-mono); font-size: .82em;
  color: var(--cc, var(--ex));
  background: var(--cc-d, var(--ex-dim));
  padding: 1px 5px; border-radius: 4px;
}

/* Panels */
.panels { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.panel {
  background: var(--bg-1); border: 1px solid var(--b-subtle);
  border-radius: var(--r-lg); overflow: hidden;
  transition: border-color var(--fast);
}
.panel:hover { border-color: var(--b-default); }
.panel-head {
  padding: 10px 16px; border-bottom: 1px solid var(--b-subtle);
  display: flex; align-items: center; gap: 7px;
  font-size: .65rem; font-weight: 600; letter-spacing: .08em;
  text-transform: uppercase; color: var(--t-3);
}
.panel-head-dot { width: 4px; height: 4px; border-radius: 50%; background: var(--cc, var(--ex)); opacity: .7; }

/* Data table */
.dt { width: 100%; border-collapse: collapse; }
.dt th {
  background: var(--bg-2); font-family: var(--f-mono);
  font-size: .6rem; font-weight: 600; letter-spacing: .07em;
  text-transform: uppercase; color: var(--t-3);
  padding: 7px 14px; text-align: left; border-bottom: 1px solid var(--b-subtle);
}
.dt td {
  font-family: var(--f-mono); font-size: .74rem;
  padding: 6px 14px; border-bottom: 1px solid var(--b-subtle); color: var(--t-1);
}
.dt tr:last-child td { border-bottom: none; }
.dt tr:hover td { background: rgba(255,255,255,.015); }
.dt-more { color: var(--t-3) !important; font-size: .65rem !important; text-align: center !important; }

/* Refs */
.refs { padding: 12px 14px; display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.ref {
  display: flex; align-items: center; gap: 7px; padding: 7px 10px;
  background: var(--bg-2); border: 1px solid var(--b-subtle); border-radius: var(--r-sm);
}
.ref-dot { width: 4px; height: 4px; border-radius: 50%; background: var(--cc, var(--ex)); flex-shrink: 0; }
.ref-val { font-family: var(--f-mono); font-size: .74rem; color: var(--cc, var(--ex)); }
.ref-lbl { font-size: .58rem; color: var(--t-3); }
.refs-note { padding: 0 14px 10px; font-size: .7rem; color: var(--t-3); line-height: 1.6; }

/* ── ANSWER SECTION ── */
.answer-wrap {
  background: var(--bg-1); border: 1px solid var(--b-subtle);
  border-radius: var(--r-lg); overflow: hidden;
}
.answer-bar {
  display: flex; align-items: flex-start;
  padding: 12px 16px; background: var(--bg-2);
  border-bottom: 1px solid var(--b-subtle); gap: 10px;
}
.answer-label {
  font-family: var(--f-mono); font-size: .68rem; font-weight: 600;
  color: var(--cc, var(--ex));
  background: var(--cc-d, var(--ex-dim));
  border: 1px solid var(--cc-g, var(--ex-glow));
  border-radius: var(--r-sm); padding: 3px 9px;
  white-space: nowrap; flex-shrink: 0; margin-top: 2px;
}
.answer-input {
  flex: 1; background: transparent; border: none; outline: none;
  font-family: var(--f-mono); font-size: .85rem;
  color: var(--t-1); caret-color: var(--cc, var(--ex));
  resize: none; line-height: 1.6; min-height: 26px; padding-top: 1px;
}
.answer-input::placeholder { color: var(--t-4); }
.answer-input:read-only { color: var(--t-3); cursor: default; }
.answer-count {
  font-family: var(--f-mono); font-size: .62rem; color: var(--t-4);
  flex-shrink: 0; padding-top: 3px;
}

.answer-actions {
  padding: 11px 16px;
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
}
.hints-row { display: flex; gap: 7px; margin-left: auto; flex-wrap: wrap; }

/* Buttons */
.btn {
  font-size: .78rem; font-weight: 600;
  padding: 8px 18px; border-radius: var(--r-md);
  border: none; cursor: pointer;
  display: inline-flex; align-items: center; gap: 6px;
  transition: all var(--fast); letter-spacing: -.01em;
}
.btn:disabled { opacity: .4; cursor: not-allowed; transform: none !important; }
.btn-primary {
  background: var(--cc, var(--ex)); color: #fff;
}
.btn-primary:hover:not(:disabled) { filter: brightness(1.1); transform: translateY(-1px); box-shadow: 0 4px 16px var(--cc-g, var(--ex-glow)); }
.btn-ghost {
  background: transparent; color: var(--t-3);
  border: 1px solid var(--b-subtle);
}
.btn-ghost:hover:not(:disabled) { color: var(--t-1); border-color: var(--b-default); }
.btn-next { background: var(--cc, var(--ex)); color: #fff; }
.btn-next:hover { filter: brightness(1.1); }

.btn-hint {
  font-family: var(--f-mono); font-size: .64rem;
  padding: 6px 11px; background: transparent;
  border: 1px solid var(--b-subtle); color: var(--t-3);
  border-radius: var(--r-md); cursor: pointer;
  display: inline-flex; align-items: center; gap: 5px;
  transition: all var(--fast);
}
.btn-hint:hover:not(.used) { border-color: var(--warn); color: var(--warn); background: var(--warn-d); }
.btn-hint.used { opacity: .3; pointer-events: none; }
.btn-hint-cost { color: var(--err); font-size: .58rem; }

/* Feedback */
.feedback {
  padding: 12px 16px; border-top: 1px solid var(--b-subtle);
  display: none; align-items: flex-start; gap: 11px;
  animation: fadeUp var(--fast) var(--ease);
}
.feedback.show { display: flex; }
.fb-success { background: linear-gradient(90deg, rgba(52,211,153,.04), transparent); }
.fb-error   { background: linear-gradient(90deg, rgba(248,113,113,.04), transparent); }
.fb-icon    { font-size: 1.1rem; flex-shrink: 0; }
.fb-title   { font-size: .83rem; font-weight: 600; margin-bottom: 2px; }
.fb-success .fb-title { color: var(--ok); }
.fb-error   .fb-title { color: var(--err); }
.fb-msg     { font-size: .78rem; color: var(--t-3); line-height: 1.5; }

/* Hints */
.hint-list {
  padding: 12px 16px 14px; border-top: 1px solid var(--b-subtle);
  display: none; flex-direction: column; gap: 7px;
}
.hint-list.show { display: flex; }
.hint-item {
  padding: 10px 13px;
  background: var(--warn-d);
  border: 1px solid rgba(251,191,36,.18);
  border-radius: var(--r-md);
  font-size: .8rem; color: var(--warn);
  display: flex; gap: 8px; align-items: flex-start; line-height: 1.55;
  animation: fadeUp var(--fast) var(--ease);
}

/* Expected */
.expected {
  padding: 8px 16px; border-top: 1px solid var(--b-subtle);
  font-family: var(--f-mono); font-size: .7rem; color: var(--t-3);
  display: none;
}
.expected.show { display: block; }
.expected-val { color: var(--cc, var(--ex)); }

/* Footer */
.page-footer {
  border-top: 1px solid var(--b-subtle);
  padding: 14px 28px;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 8px;
  position: relative; z-index: 1;
}
.footer-left { font-size: .72rem; color: var(--t-3); }
.footer-left a { color: var(--cc, var(--ex)); }
.footer-right { font-family: var(--f-mono); font-size: .62rem; color: var(--t-4); }

/* Responsive */
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .main { padding: 18px 16px; }
  .nav  { padding: 0 16px; }
  .panels { grid-template-columns: 1fr; }
  .ch-title { font-size: 1.3rem; }
}