:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --accent: #38bdf8;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --border: #334155;
  --font-heading: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --font-body: 'Inter', 'Roboto', sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-header,
.site-footer {
  padding: 1.5rem 3vw;
  background: rgba(15, 23, 42, 0.8);
  border-bottom: 1px solid var(--border);
}

.site-footer {
  border-top: 1px solid var(--border);
  border-bottom: none;
  margin-top: auto;
  text-align: center;
  color: var(--muted);
}

.site-header h1 {
  margin: 0;
  font-family: var(--font-heading);
  letter-spacing: 0.02em;
}

.site-header p {
  margin: 0.5rem 0 0;
  max-width: 60ch;
  color: var(--muted);
}

.module-nav {
  display: flex;
  gap: 0.75rem;
  padding: 1rem 3vw;
  background: rgba(15, 23, 42, 0.6);
  border-bottom: 1px solid var(--border);
}

.nav-btn {
  padding: 0.65rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.nav-btn:hover:not(:disabled) {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.nav-btn:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.layout {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.5rem;
  padding: 1.5rem 3vw 3rem;
}

.panel {
  background: var(--panel);
  border: 1px solid rgba(148, 163, 184, 0.1);
  border-radius: 1rem;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  min-height: 320px;
}

.panel h2 {
  margin-top: 0;
  font-family: var(--font-heading);
  font-size: 1.15rem;
}

.panel .content {
  flex: 1;
  padding-top: 0.5rem;
  overflow: hidden;
}

.placeholder-chart {
  border: 1px dashed var(--border);
  border-radius: 0.75rem;
  display: grid;
  place-content: center;
  color: var(--muted);
  font-size: 0.95rem;
}

@media (max-width: 1024px) {
  .layout {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 768px) {
  .module-nav {
    flex-wrap: wrap;
  }

  .layout {
    grid-template-columns: 1fr;
  }
}

.nav-btn.active {
  border-color: var(--accent);
  background: rgba(56, 189, 248, 0.15);
}

.control-form {
  display: grid;
  gap: 1.25rem;
}

.control-form fieldset {
  border: 1px solid rgba(148, 163, 184, 0.2);
  border-radius: 0.75rem;
  padding: 1rem;
  display: grid;
  gap: 0.75rem;
}

.control-form legend {
  padding: 0 0.35rem;
  font-weight: 600;
  color: var(--accent);
}

.control-form label {
  display: grid;
  gap: 0.35rem;
  font-size: 0.95rem;
  color: var(--text);
}

.control-form input[type="range"] {
  width: 100%;
}

.control-form select,
.control-form input[type="number"],
.control-form input[type="text"] {
  padding: 0.45rem 0.6rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border);
  background: rgba(148, 163, 184, 0.05);
  color: var(--text);
}

.checkbox {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
}

.checkbox input[type="checkbox"] {
  width: 1.1rem;
  height: 1.1rem;
  accent-color: var(--accent);
}

.control-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.control-buttons button.secondary {
  border-color: rgba(148, 163, 184, 0.4);
  background: rgba(148, 163, 184, 0.1);
}

.prediction-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.prediction-item {
  border: 1px solid rgba(148, 163, 184, 0.2);
  border-radius: 0.75rem;
  padding: 0.75rem;
  background: rgba(15, 23, 42, 0.45);
  font-size: 0.95rem;
}

.prediction-item .score {
  color: var(--accent);
}

.prediction-item .text {
  display: block;
  margin-top: 0.35rem;
  color: var(--muted);
}

.prediction-item em {
  color: var(--text);
}

.control-form button {
  justify-self: start;
  padding: 0.5rem 0.85rem;
  border-radius: 0.5rem;
  border: 1px solid var(--accent);
  background: rgba(56, 189, 248, 0.15);
  color: var(--text);
  cursor: pointer;
  transition: transform 0.2s ease;
}

.control-form button:hover {
  transform: translateY(-1px);
}

.value-tag {
  font-size: 0.85rem;
  color: var(--muted);
}

.metrics {
  margin-top: 0.5rem;
  padding: 1rem;
  border: 1px solid rgba(148, 163, 184, 0.15);
  border-radius: 0.75rem;
  background: rgba(15, 23, 42, 0.4);
}

.metrics h4 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.metrics ul {
  margin: 0;
  padding-left: 1.1rem;
  display: grid;
  gap: 0.35rem;
}

.metrics .metric-table {
  width: 100%;
  border-collapse: collapse;
  margin: 0.5rem 0 1rem;
  font-size: 0.9rem;
}

.metrics .metric-table th,
.metrics .metric-table td {
  border: 1px solid rgba(148, 163, 184, 0.2);
  padding: 0.5rem;
  text-align: left;
}

.metrics .metric-table th {
  background: rgba(148, 163, 184, 0.12);
  color: var(--accent);
}

.metrics .metric-grid {
  margin-top: 1rem;
  display: grid;
  gap: 0.75rem;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.metrics .metric-card {
  border: 1px solid rgba(148, 163, 184, 0.25);
  border-radius: 0.65rem;
  padding: 0.75rem;
  background: rgba(15, 23, 42, 0.55);
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.1);
}

.metrics .metric-card h5 {
  margin: 0 0 0.35rem;
  font-size: 0.95rem;
}

.metrics .metric-card p {
  margin: 0.2rem 0 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.chart {
  width: 100%;
  min-height: 320px;
  max-width: 100%;
}

.loss-chart {
  margin-top: 1.5rem;
}

.theory-content .math {
  font-family: 'Times New Roman', serif;
  color: #f8fafc;
}