/* ============================================================
   Atomify · v2 · equations (page)
   ------------------------------------------------------------
   Stoichiometric balancer. Relies on core.css + components.css.
   ============================================================ */

/* ─── 1 · Form layout ───────────────────────────────── */
.eq-form { display: block; }

.eq-form-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: stretch;
}
@media (max-width: 720px) {
  .eq-form-row { grid-template-columns: 1fr; }
  .eq-form-row .btn-cta { width: 100%; }
}

.eq-form-aux {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 14px;
}
.eq-hint {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.04em;
  color: var(--ink-muted);
}
.eq-hint code {
  font-family: var(--font-mono);
  background: var(--paper-tint);
  padding: 1px 6px;
  border-radius: 3px;
  color: var(--ink-2);
}
@media (max-width: 540px) {
  .eq-form-aux {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
}

/* Equation input is wider/lower-key than masa's formula input */
.field--equation .field-input {
  font-family: var(--font-display);
  font-variation-settings: "opsz" 24;
  font-size: 1.2rem;
  font-weight: 500;
  letter-spacing: -0.005em;
}

/* ─── 2 · Example library ───────────────────────────── */
.eq-examples {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  border: 1px solid var(--line);
  border-radius: var(--r-3);
  overflow: hidden;
  background: var(--paper-2);
}

.eq-example {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0;
  padding: 1.25rem 1.25rem 1.15rem;
  min-height: 158px;
  background: var(--paper-2);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  color: inherit;
  margin: 0;
  transition: background-color 180ms ease, transform 120ms var(--ease-soft);
}
.eq-example > .eq-example-num       { margin-bottom: 0.85rem; }
.eq-example > .eq-example-reactants { margin-bottom: 0.3rem; }
.eq-example > .eq-example-products  { margin-bottom: auto; }
.eq-example > .eq-example-name      { padding-top: 0.85rem; }
.eq-example:hover { background: var(--paper); z-index: 2; }
.eq-example:active { transform: translateY(1px); }
.eq-example:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: -2px;
  z-index: 3;
}

.eq-example-num {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.12em;
  color: var(--ink-muted);
  text-transform: uppercase;
}
.eq-example-reactants,
.eq-example-products {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 1.2rem;
  letter-spacing: -0.01em;
  color: var(--ink);
  line-height: 1.15;
  transition: color 180ms ease;
  display: block;
  min-width: 0;
  word-break: break-word;
}
.eq-example-reactants sub,
.eq-example-products sub {
  font-size: 0.6em;
  font-weight: 500;
  vertical-align: -0.18em;
}
.eq-example-products {
  position: relative;
  padding-left: 1.25rem;
  color: var(--ink-2);
}
.eq-example-products::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.45em;
  width: 0.85rem;
  height: 1px;
  background: var(--ink-muted);
}
.eq-example-products::after {
  content: '';
  position: absolute;
  left: 0.6rem;
  top: calc(0.45em - 4px);
  width: 6px;
  height: 6px;
  border-right: 1px solid var(--ink-muted);
  border-top: 1px solid var(--ink-muted);
  transform: rotate(45deg);
}
.eq-example:hover .eq-example-reactants,
.eq-example:hover .eq-example-products {
  color: var(--green-deep);
}
[data-theme="dark"] .eq-example:hover .eq-example-reactants,
[data-theme="dark"] .eq-example:hover .eq-example-products,
body.dark-mode .eq-example:hover .eq-example-reactants,
body.dark-mode .eq-example:hover .eq-example-products { color: var(--green); }
.eq-example-name {
  font-family: var(--font-body);
  font-size: 0.82rem;
  color: var(--ink-soft);
  line-height: 1.3;
}

/* ─── 3 · Result panel ─────────────────────────────── */
.eq-panel {
  margin-top: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--r-4);
  background: var(--paper-2);
  overflow: hidden;
  animation: result-rise 0.5s var(--ease-out) both;
}
@keyframes result-rise {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.eq-panel-head {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1.5rem;
  padding: 1.5rem 1.75rem;
  border-bottom: 1px solid var(--line);
  align-items: start;
}
.eq-panel-head .label-mono {
  display: block;
  margin-bottom: 0.7rem;
}

/* The balanced equation itself — display headline */
.eq-display {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.4rem, 2.6vw, 2rem);
  letter-spacing: -0.018em;
  line-height: 1.3;
  color: var(--ink);
  word-break: break-word;
}
.eq-display sub {
  font-size: 0.55em;
  font-weight: 500;
  vertical-align: -0.2em;
}
.eq-coef {
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
  font-weight: 500;
  font-size: 0.78em;
  margin-right: 0.18em;
  color: var(--green-deep);
  vertical-align: 0.05em;
}
[data-theme="dark"] .eq-coef,
body.dark-mode .eq-coef { color: var(--green); }
.eq-plus {
  color: var(--ink-muted);
  margin: 0 0.5em;
  font-weight: 400;
}
.eq-arrow {
  display: inline-block;
  width: 2em;
  height: 0.05em;
  background: var(--ink-3);
  position: relative;
  vertical-align: middle;
  margin: 0 0.7em;
}
.eq-arrow::before,
.eq-arrow::after {
  content: '';
  position: absolute;
  right: 0;
  width: 0.5em;
  height: 1px;
  background: var(--ink-3);
}
.eq-arrow::before { transform: rotate(35deg); transform-origin: right; bottom: 0; }
.eq-arrow::after  { transform: rotate(-35deg); transform-origin: right; top: 0; }

.eq-copy {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--r-2);
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink-2);
  cursor: pointer;
  transition: background-color 150ms, border-color 150ms, color 150ms;
}
.eq-copy:hover { background: var(--paper-3); border-color: var(--line-strong); color: var(--ink); }
.eq-copy svg { width: 14px; height: 14px; }
.eq-copy.is-copied {
  color: var(--green-deep);
  border-color: var(--green-tint);
  background: var(--green-tint);
}
[data-theme="dark"] .eq-copy.is-copied,
body.dark-mode .eq-copy.is-copied { color: var(--green); }

@media (max-width: 720px) {
  .eq-panel-head { grid-template-columns: 1fr; }
}

/* Substances list (replaces table) */
.eq-substances {
  padding: 0.5rem 0;
}
.eq-row {
  display: grid;
  grid-template-columns: 64px 1.2fr 1fr 1.4fr;
  gap: 1.5rem;
  padding: 1rem 1.75rem;
  border-bottom: 1px solid var(--line-soft);
  align-items: center;
}
.eq-row:last-child { border-bottom: 0; }
.eq-row--reactant { background: transparent; }
.eq-row--product  { background: var(--paper); }

/* Side label between reactants and products */
.eq-divider {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 0.85rem 1.75rem;
  background: var(--paper);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.eq-divider::before,
.eq-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--line-strong);
  max-width: 80px;
}
.eq-divider-text {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.eq-row-coef {
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
  font-weight: 500;
  font-size: 1.4rem;
  color: var(--green-deep);
  text-align: center;
  letter-spacing: -0.01em;
}
[data-theme="dark"] .eq-row-coef,
body.dark-mode .eq-row-coef { color: var(--green); }

.eq-row-formula {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  color: var(--ink);
  line-height: 1;
}
.eq-row-formula sub {
  font-size: 0.55em;
  font-weight: 500;
  vertical-align: -0.2em;
}

.eq-row-mass {
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
  font-size: 0.95rem;
  color: var(--ink-2);
  white-space: nowrap;
}
.eq-row-mass-unit {
  color: var(--ink-muted);
  font-size: 0.78rem;
  margin-left: 0.3rem;
}

.eq-row-elements {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.eq-elem {
  display: inline-flex;
  align-items: baseline;
  gap: 0.3rem;
  padding: 3px 9px;
  border-radius: 999px;
  background: var(--paper-3);
  border: 1px solid var(--line);
  font-family: var(--font-body);
  font-size: 0.78rem;
  color: var(--ink-2);
}
.eq-elem-sym {
  font-family: var(--font-display);
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.eq-elem-pct {
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
  color: var(--ink-soft);
  font-size: 0.72rem;
}

@media (max-width: 720px) {
  .eq-row {
    grid-template-columns: 48px 1fr;
    grid-template-rows: auto auto auto;
    gap: 0.5rem 1rem;
    padding: 1rem 1.25rem;
  }
  .eq-row-coef { grid-row: 1 / span 2; align-self: start; padding-top: 0.15rem; }
  .eq-row-formula { grid-column: 2; }
  .eq-row-mass { grid-column: 2; font-size: 0.86rem; }
  .eq-row-elements { grid-column: 1 / -1; margin-top: 0.2rem; }
  .eq-divider { padding: 0.7rem 1.25rem; }
}

/* Toast for copy success */
.eq-toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--ink);
  color: var(--paper);
  padding: 0.75rem 1.25rem;
  border-radius: var(--r-3);
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition:
    transform 280ms var(--ease-out),
    opacity 200ms ease;
  z-index: 9000;
}
.eq-toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}
[data-theme="dark"] .eq-toast,
body.dark-mode .eq-toast {
  background: var(--paper);
  color: var(--ink);
}