/* ═══════════════════════════════════════════════════════
   Energy Transfer — Clay Design System Extensions
   Only page-specific overrides. Everything else comes from
   clay-system.css + content.css.
   ═══════════════════════════════════════════════════════ */

/* ── Sidebar Toggle Button ── */
.sidebar-toggle {
  display: none;
  position: fixed;
  top: 72px;
  left: 12px;
  z-index: 200;
  align-items: center;
  gap: 6px;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(160,150,180,0.15);
  border-radius: 20px;
  padding: 8px 14px;
  font-family: var(--font-heading);
  font-size: 13px;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease-smooth);
  box-shadow: var(--shadow-card);
}
.sidebar-toggle:hover {
  background: rgba(255,255,255,1);
  border-color: var(--accent);
  color: var(--accent);
}
.sidebar-toggle i {
  font-size: 14px;
}

/* ── Content Sidebar ── */
.content-sidebar {
  position: fixed;
  top: 64px;
  left: 0;
  bottom: 0;
  z-index: 150;
  width: 220px;
  background: rgba(255,255,255,0.80);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-right: 1px solid rgba(160,150,180,0.12);
  overflow-y: auto;
  padding: 20px 0;
  transition: transform 0.35s var(--ease-smooth);
  display: flex;
  flex-direction: column;
  scrollbar-width: thin;
  scrollbar-color: rgba(160,150,180,0.2) transparent;
}
.content-sidebar::-webkit-scrollbar { width: 4px; }
.content-sidebar::-webkit-scrollbar-thumb { background: rgba(160,150,180,0.2); border-radius: 4px; }

.content-sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 20px 16px;
  border-bottom: 1px solid rgba(160,150,180,0.08);
  margin-bottom: 12px;
}
.content-sidebar-brand {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 15px;
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}
.sidebar-close {
  display: none;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 18px;
  cursor: pointer;
  padding: 4px;
  border-radius: 8px;
  transition: all var(--dur-fast);
}
.sidebar-close:hover {
  background: rgba(160,150,180,0.1);
  color: var(--text-primary);
}

.content-sidebar-links {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 0 12px;
}
.content-sidebar-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  text-decoration: none;
  transition: all var(--dur-fast) var(--ease-smooth);
  font-family: var(--font-heading);
}
.content-sidebar-link:hover {
  background: rgba(124,58,237,0.06);
  color: var(--text-primary);
}
.content-sidebar-link.active {
  background: rgba(124,58,237,0.1);
  color: var(--accent);
}
.sidebar-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 8px;
  background: rgba(160,150,180,0.1);
  font-size: 11px;
  font-weight: 800;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: all var(--dur-fast);
}
.content-sidebar-link.active .sidebar-num {
  background: rgba(124,58,237,0.15);
  color: var(--accent);
}
.sidebar-label {
  line-height: 1.2;
}

/* ── Content Main ── */
.content-main {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
  transition: all 0.35s var(--ease-smooth);
}


/* ── Main content area ── */
.content-main {
  margin-left: 268px;
  margin-top: 80px;
  padding: 16px 24px 48px;
  max-width: 900px;
  position: relative;
  z-index: 1;
}

/* ── Page heading ── */
.content-main > .page-header h1 {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: clamp(2rem, 4vw, 3rem);
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-align: center;
  margin-bottom: 32px;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

/* ── Sidebar toggle button (mobile) ── */
.sidebar-toggle {
  display: none;
  position: fixed;
  top: 78px;
  left: 12px;
  z-index: 600;
  width: 40px;
  height: 40px;
  border-radius: 14px;
  background: rgba(255,255,255,0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(160,150,180,0.15);
  box-shadow: var(--shadow-card);
  cursor: pointer;
  font-size: 18px;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  transition: all var(--dur-fast);
}
.sidebar-toggle:hover {
  color: var(--accent);
  background: rgba(255,255,255,0.95);
}
@media (max-width: 900px) {
  .sidebar-toggle { display: flex; }
}

/* ── Mobile ── */
@media (max-width: 900px) {
  .content-sidebar {
    left: 12px;
    right: 12px;
    width: auto;
    top: 76px;
    bottom: auto;
    max-height: calc(100vh - 100px);
    transform: translateX(-120%);
    opacity: 0;
    padding: 12px 8px;
  }
  .content-sidebar.open {
    transform: translateX(0);
    opacity: 1;
  }
  .content-sidebar .sidebar-close { display: flex; }
  .content-main {
    margin-left: 0;
    margin-top: 72px;
    padding: 12px 16px 32px;
  }
}

/* ── Card icons ── */
.card h2 .icon {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, var(--accent-light), var(--accent));
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; flex-shrink: 0;
}

/* ── Learning Outcomes (.lo) ── */
.lo {
  background: rgba(124,58,237,0.04);
  border-left: 4px solid var(--accent);
  border-radius: 16px;
  padding: 16px 20px;
  margin-bottom: 20px;
}
.lo h4 {
  font-family: var(--font-heading);
  font-size: 14px;
  color: var(--accent);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.lo ul { list-style: none; padding: 0; }
.lo li {
  font-size: 14px;
  color: var(--text-muted);
  padding: 4px 0;
  padding-left: 20px;
  position: relative;
}
.lo li::before { content: "✓"; position: absolute; left: 0; color: var(--accent-emerald); font-weight: 700; }
.lo p { color: var(--text-muted); font-size: 14px; margin-top: 8px; }

/* ── Formula ── */
.formula {
  background: linear-gradient(135deg, rgba(124,58,237,0.05), rgba(219,39,119,0.04));
  border-radius: 20px;
  padding: 20px 24px;
  margin: 16px 0;
  text-align: center;
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

/* ── Example box ── */
.example {
  background: rgba(245,158,11,0.04);
  border-left: 4px solid var(--accent-amber);
  border-radius: 16px;
  padding: 14px 18px;
  margin: 14px 0;
  font-size: 14px;
  color: var(--text-muted);
}
.example p { color: var(--text-muted); }
.example ol { padding-left: 20px; }

/* ── Practical note (.pnote) ── */
.pnote {
  background: rgba(16,185,129,0.04);
  border-left: 4px solid var(--accent-emerald);
  border-radius: 16px;
  padding: 14px 18px;
  margin: 14px 0;
  font-size: 14px;
  color: var(--text-muted);
}

/* ── Explanation ── */
.explanation {
  background: rgba(14,165,233,0.04);
  border-left: 4px solid var(--accent-blue);
  border-radius: 16px;
  padding: 14px 18px;
  margin: 14px 0;
  font-size: 14px;
  color: var(--text-muted);
  font-style: italic;
}

/* ── Grid 2 ── */
.grid2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 12px 0;
}
@media (max-width: 600px) { .grid2 { grid-template-columns: 1fr; } }
.grid2 div {
  background: rgba(124,58,237,0.03);
  border-radius: 14px;
  padding: 12px 16px;
  font-size: 14px;
  color: var(--text-muted);
}

/* ── Sim wrap ── */
.sim-wrap {
  background: linear-gradient(135deg, rgba(16,185,129,0.04), rgba(14,165,233,0.03));
  border: 1px solid rgba(160,150,180,0.1);
  border-radius: 24px;
  padding: 24px;
  margin: 20px 0;
  transition: all var(--dur-med) var(--ease-smooth);
}
.sim-wrap:hover { border-color: rgba(124,58,237,0.25); }
.sim-wrap h4 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 8px;
}
.sim-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin: 10px 0;
}
.sim-controls label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
}
.sim-controls input[type="range"] { accent-color: var(--accent); width: 120px; }
.sim-controls input[type="checkbox"] { accent-color: var(--accent); }
canvas { display: block; width: 100%; border-radius: 16px; background: #f8f7fc; }

/* ── Energy bars ── */
.energy-bars { display: flex; gap: 16px; flex-wrap: wrap; margin-top: 10px; }
.ebar { flex: 1; min-width: 100px; }
.ebar-label { font-size: 12px; font-weight: 600; margin-bottom: 4px; display: flex; justify-content: space-between; font-family: var(--font-heading); }
.ebar-track { height: 16px; background: rgba(160,150,180,0.15); border-radius: 10px; overflow: hidden; }
.ebar-fill { height: 100%; border-radius: 10px; transition: width .05s linear; }
.fill-gpe { background: linear-gradient(90deg, var(--accent-emerald), #34d399); }
.fill-ke { background: linear-gradient(90deg, var(--accent-amber), #fbbf24); }
.fill-th { background: linear-gradient(90deg, var(--accent-rose), #f87171); }
.fill-tot { background: linear-gradient(90deg, var(--accent), var(--accent-light)); }

/* ── SVG Diagrams ── */
.diagram { background: rgba(255,255,255,0.5); border-radius: 20px; padding: 16px; margin: 16px 0; border: 1px solid rgba(160,150,180,0.1); text-align: center; }
.diagram svg { max-width: 100%; height: auto; border-radius: 12px; }

/* ── Insulation Table ── */
.ins-table { width: 100%; border-collapse: separate; border-spacing: 0; border-radius: 16px; overflow: hidden; margin: 16px 0; font-size: 14px; }
.ins-table th { background: rgba(124,58,237,0.06); color: var(--accent); font-weight: 700; padding: 12px 16px; text-align: left; font-family: var(--font-heading); }
.ins-table td { padding: 10px 16px; border-bottom: 1px solid rgba(160,150,180,0.08); color: var(--text-muted); }
.ins-table tr:last-child td { border-bottom: none; }
.ins-table tr:hover td { background: rgba(124,58,237,0.03); }

/* ── Result ── */
.result {
  background: rgba(16,185,129,0.06);
  border: 1px solid rgba(16,185,129,0.2);
  border-radius: 20px;
  padding: 16px 20px;
  margin-top: 16px;
  text-align: center;
  font-weight: 700;
  color: var(--accent-emerald);
  opacity: 0;
  transform: translateY(10px);
  transition: all 0.3s var(--ease-smooth);
}
.result.show { opacity: 1; transform: translateY(0); }

/* ── Working out ── */
.wo { background: rgba(255,255,255,0.5); border-radius: 16px; padding: 16px; margin-top: 16px; border-left: 4px solid var(--accent-blue); }
.wo-step { padding: 8px; margin-bottom: 8px; border-left: 3px solid var(--accent); font-size: 13px; color: var(--text-muted); }
.wo-step .num { display: inline-flex; align-items: center; justify-content: center; width: 24px; height: 24px; background: linear-gradient(135deg, var(--accent-light), var(--accent)); color: #fff; border-radius: 50%; font-size: 12px; font-weight: 700; margin-right: 8px; }
.wo-calc { font-family: var(--font-heading); background: rgba(160,150,180,0.08); padding: 6px; border-radius: 8px; margin: 4px 0; font-size: 14px; }
.wo-final { background: linear-gradient(135deg, var(--accent-emerald), #34d399); color: #fff; padding: 14px; border-radius: 16px; text-align: center; font-size: 1.05rem; font-weight: 700; margin-top: 12px; font-family: var(--font-heading); }

/* ── Quiz ── */
#quiz-box { border-radius: 24px; padding: 24px; border: 1px solid rgba(160,150,180,0.1); background: rgba(255,255,255,0.4); }
.quiz-q { background: rgba(255,255,255,0.5); backdrop-filter: blur(8px); border: 1px solid rgba(160,150,180,0.1); border-radius: 20px; padding: 20px; margin-bottom: 16px; transition: all var(--dur-med) var(--ease-smooth); }
.quiz-q:hover { background: rgba(255,255,255,0.7); }
.quiz-q.correct { border-color: var(--accent-emerald); }
.quiz-q.wrong { border-color: var(--accent-rose); }
.quiz-q p { font-weight: 700; color: var(--text-primary); margin-bottom: 12px; font-family: var(--font-heading); }
.quiz-q label { display: block; padding: 8px 14px; margin: 4px 0; border-radius: 14px; font-size: 14px; color: var(--text-muted); cursor: pointer; transition: background var(--dur-fast); }
.quiz-q label:hover { background: rgba(124,58,237,0.05); }
.quiz-q input[type="radio"] { margin-right: 10px; accent-color: var(--accent); }

/* ── SVG Sankey ── */
#sankey-svg { width: 100%; max-width: 550px; margin: 16px auto; display: block; }

/* ── Footer override ── */
.foot { text-align: center; color: var(--text-muted); padding: 24px; font-size: 13px; }

/* ── Button overrides ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  border: none; border-radius: var(--radius-btn);
  font-family: var(--font-body); font-size: 14px; font-weight: 700;
  padding: 10px 22px; cursor: pointer; transition: all var(--dur-fast);
  text-decoration: none; line-height: 1; min-height: 44px;
  background: linear-gradient(135deg, var(--accent-light), var(--accent));
  color: #fff; box-shadow: var(--shadow-btn);
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-btn-hover); }
.btn:active { transform: scale(0.95); box-shadow: var(--shadow-pressed); }
.btn-warn { background: linear-gradient(135deg, #FBBF24, var(--accent-amber)); color: #fff; }
.btn-warn:hover { transform: translateY(-2px); box-shadow: var(--shadow-btn-hover); }
.btn-warn:active { transform: scale(0.95); }
.btn-ok { background: linear-gradient(135deg, #34D399, var(--accent-emerald)); color: #fff; }
.btn-err { background: linear-gradient(135deg, #FB7185, var(--accent-rose)); color: #fff; }

/* ── Input styles ── */
input[type="number"], select {
  width: 100%; padding: 10px 16px;
  border: 2px solid rgba(160,150,180,0.15);
  border-radius: 16px; font-size: 15px;
  background: #EFEBF5; color: var(--text-primary);
  font-family: var(--font-body); transition: all var(--dur-fast);
}
input[type="number"]:focus, select:focus {
  outline: none; background: #fff;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(124,58,237,0.12);
}
label { font-weight: 600; color: var(--text-muted); font-size: 13px; display: block; margin-bottom: 4px; }

/* ── Mobile ── */
@media (max-width: 768px) {
  .content-main { padding: 12px 16px 32px; }
  .card { padding: 20px; }
  .sim-wrap { padding: 16px; }
}
@media(max-width:768px){
  .sidebar-toggle{display:flex}
  .content-sidebar{transform:translateX(-100%);width:260px}
  .content-sidebar.open{transform:translateX(0)}
  .sidebar-close{display:block}
  .content-main{padding:0 16px;margin-left:0}
}