/* Solver page styles */

.solver-page {
  max-width: 960px;
  margin: 0 auto;
  padding: 3.5rem 1.5rem 5rem;
}

.solver-head {
  margin-bottom: 2.5rem;
}
.solver-head .eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--color-warm);
  margin: 0 0 0.75rem;
}
.solver-head h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.75rem);
  line-height: 1.05;
  margin: 0 0 0.85rem;
  color: var(--color-text);
  letter-spacing: -0.01em;
}
.solver-head .lede {
  font-size: 1.05rem;
  line-height: 1.55;
  max-width: 42rem;
  color: var(--color-text-muted);
  margin: 0;
}

/* Mode tabs */
.solver-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--color-divider);
}
.solver-tab {
  flex: 1;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 0.9rem 0.75rem;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  color: var(--color-text-muted);
  transition: color 0.15s, border-color 0.15s;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-width: 0;
}
.solver-tab:hover { color: var(--color-text); }
.solver-tab.is-active {
  color: var(--color-text);
  border-bottom-color: var(--color-accent);
}
.solver-tab .tab-label {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
}
.solver-tab .tab-hint {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--color-text-muted);
  opacity: 0.8;
}

/* Input panel */
.solver-input {
  background: var(--color-surface-offset);
  border: 1px solid var(--color-divider);
  border-radius: 14px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}
.input-panel.is-hidden { display: none; }

.input-mode-toggle {
  display: inline-flex;
  gap: 0.25rem;
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: 999px;
  padding: 0.25rem;
  margin-bottom: 1.25rem;
}
.mode-btn {
  border: none;
  background: none;
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  transition: background 0.15s, color 0.15s;
}
.mode-btn.is-active {
  background: var(--color-accent);
  color: var(--color-surface);
}

.sr-label {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0);
  white-space: nowrap; border: 0;
}

.input-body.is-hidden { display: none; }

.text-row {
  display: flex;
  gap: 0.75rem;
  align-items: stretch;
  margin-bottom: 0.75rem;
}
.eq-input {
  flex: 1;
  min-width: 0;
  padding: 0.85rem 1rem;
  border: 1.5px solid var(--color-divider);
  border-radius: 10px;
  background: var(--color-surface);
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--color-text);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.eq-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--color-accent) 20%, transparent);
}

.btn-solve {
  padding: 0.85rem 1.4rem;
  background: var(--color-accent);
  color: var(--color-surface);
  border: none;
  border-radius: 10px;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.1s, filter 0.15s;
  white-space: nowrap;
}
.btn-solve:hover { filter: brightness(1.08); }
.btn-solve:active { transform: translateY(1px); }

.input-hint {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin: 0.5rem 0 1rem;
  line-height: 1.5;
}
.input-hint code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--color-surface);
  padding: 0.05em 0.4em;
  border-radius: 4px;
  border: 1px solid var(--color-divider);
}

/* Example chips */
.example-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}
.ex-chip {
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: 999px;
  padding: 0.45rem 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--color-text);
  cursor: pointer;
  transition: border-color 0.15s, transform 0.1s;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.ex-chip:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}
.ex-chip:active { transform: translateY(1px); }
.chip-tag {
  font-family: var(--font-body, inherit);
  font-size: 0.7rem;
  padding: 0.1em 0.5em;
  background: var(--color-warm);
  color: var(--color-surface);
  border-radius: 999px;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  font-weight: 600;
}

/* Structured input */
.struct-label {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin: 0 0 0.75rem;
}
.struct-label code {
  font-family: var(--font-mono);
  color: var(--color-text);
}
.cmp-choice select {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  padding: 0.2rem 0.4rem;
  border: 1px solid var(--color-divider);
  border-radius: 6px;
  background: var(--color-surface);
  color: var(--color-text);
}
.struct-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
  margin-bottom: 1rem;
}
.struct-grid-sys { grid-template-columns: repeat(3, 1fr); }
.struct-grid label {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}
.struct-grid input {
  padding: 0.55rem 0.7rem;
  border: 1.5px solid var(--color-divider);
  border-radius: 8px;
  background: var(--color-surface);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 0.95rem;
}
.struct-grid input:focus {
  outline: none;
  border-color: var(--color-accent);
}

/* Result */
.solver-result {
  min-height: 100px;
}
.result-placeholder {
  padding: 2rem;
  text-align: center;
  color: var(--color-text-muted);
  border: 1px dashed var(--color-divider);
  border-radius: 14px;
  font-size: 0.95rem;
}

.result-card {
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: 14px;
  overflow: hidden;
}

.result-headline {
  padding: 1.5rem 1.75rem 1.25rem;
  border-bottom: 1px solid var(--color-divider);
  background: linear-gradient(180deg, var(--color-surface-offset) 0%, var(--color-surface) 100%);
}
.result-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--color-warm);
  margin: 0 0 0.35rem;
}
.result-answer {
  font-family: var(--font-mono);
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  color: var(--color-text);
  margin: 0;
  font-weight: 500;
  letter-spacing: -0.005em;
  line-height: 1.3;
  word-break: break-word;
}

.result-viz {
  padding: 1rem 1.25rem 0.5rem;
  min-height: 140px;
}
.result-viz canvas { display: block; }

.result-steps {
  border-top: 1px solid var(--color-divider);
}
.result-steps > summary {
  cursor: pointer;
  padding: 1rem 1.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  list-style: none;
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  user-select: none;
  transition: background 0.12s;
}
.result-steps > summary::-webkit-details-marker { display: none; }
.result-steps > summary:hover { background: var(--color-surface-offset); }
.result-steps > summary::after {
  content: '›';
  font-size: 1.4rem;
  line-height: 1;
  transform: rotate(90deg);
  transition: transform 0.15s;
  color: var(--color-text-muted);
}
.result-steps[open] > summary::after { transform: rotate(270deg); }
.steps-label { color: var(--color-text); }
.steps-hint { color: var(--color-text-muted); font-size: 0.8rem; }

.steps-list {
  list-style: none;
  padding: 0.5rem 1.75rem 1.5rem;
  margin: 0;
  counter-reset: step;
}
.step {
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 0.9rem;
  padding: 0.9rem 0;
  border-bottom: 1px dashed var(--color-divider);
}
.step:last-child { border-bottom: none; }
.step-num {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  margin-top: 2px;
}
.step-content { min-width: 0; }
.step-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.98rem;
  color: var(--color-text);
  margin: 0 0 0.4rem;
}
.step-body {
  margin: 0 0 0.4rem;
  overflow-x: auto;
}
.step-body code {
  font-family: var(--font-mono);
  font-size: 0.98rem;
  color: var(--color-text);
  background: var(--color-surface-offset);
  padding: 0.35rem 0.6rem;
  border-radius: 6px;
  display: inline-block;
  border: 1px solid var(--color-divider);
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-word;
}
.step-note {
  font-size: 0.87rem;
  color: var(--color-text-muted);
  line-height: 1.5;
  margin: 0.4rem 0 0;
}

/* Error state */
.result-error {
  padding: 1.25rem 1.75rem;
  border-left: 4px solid var(--color-warm);
  background: color-mix(in oklab, var(--color-warm) 8%, var(--color-surface));
}
.result-error-title {
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 0.35rem;
}
.result-error-msg {
  margin: 0;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.5;
}

/* Responsive */
@media (max-width: 640px) {
  .solver-page { padding: 2rem 1rem 3rem; }
  .solver-tab .tab-hint { display: none; }
  .solver-tab { padding: 0.75rem 0.5rem; }
  .solver-input { padding: 1rem; }
  .text-row {
    flex-direction: column;
    gap: 0.5rem;
  }
  .btn-solve { width: 100%; }
  .struct-grid { grid-template-columns: repeat(2, 1fr); }
  .struct-grid-sys { grid-template-columns: repeat(2, 1fr); }
  .result-headline, .result-steps > summary, .steps-list {
    padding-left: 1.1rem; padding-right: 1.1rem;
  }
  .step { grid-template-columns: 28px 1fr; gap: 0.6rem; }
}