*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --bg: #07111f;
  --bg-soft: #101b2b;
  --panel-dark: rgba(9, 18, 33, 0.82);
  --panel-light: #ffffff;
  --line: rgba(10, 23, 38, 0.08);
  --text: #f5f7fb;
  --text-soft: #d6deea;
  --body: #435166;
  --blue: #69b4ff;
  --gold: #ffd54f;
  --radius: 24px;
  --shadow: 0 24px 60px rgba(4, 9, 18, 0.28);
  --circle: #4da7ff;
  --triangle: #ff8c69;
  --square: #8f7cff;
}

html,
body {
  min-height: 100%;
  margin: 0;
  font-family: 'IBM Plex Sans', 'Segoe UI', sans-serif;
  background:
    radial-gradient(circle at top right, rgba(105, 180, 255, 0.18), transparent 24%),
    linear-gradient(180deg, #07111f 0%, #101b2b 30%, #eff4fb 30%, #eff4fb 100%);
  color: var(--text);
}

.screen {
  display: none;
}

.screen.active {
  display: block;
}

.app-shell {
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px 20px 40px;
}

.intro-screen {
  min-height: calc(100vh - 48px);
  display: none;
  align-items: center;
  justify-content: center;
}

.intro-screen.active {
  display: flex;
}

.intro-card {
  width: min(1040px, 100%);
  padding: 36px;
  border-radius: 30px;
  background: rgba(9, 18, 33, 0.8);
  border: 1px solid rgba(255, 255, 255, 0.12);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.eyebrow,
.section-kicker {
  margin: 0 0 12px;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #9dd1ff;
}

.intro-card h1,
.topbar h1 {
  margin: 0;
  font-family: 'Georgia', 'Times New Roman', serif;
  letter-spacing: -0.03em;
}

.intro-card h1 {
  font-size: clamp(2.6rem, 6vw, 4rem);
}

.intro-text {
  max-width: 62ch;
  margin: 16px 0 0;
  font-family: 'Segoe UI', sans-serif;
  font-size: 1.03rem;
  line-height: 1.8;
  color: var(--text-soft);
}

.intro-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 28px;
}

.intro-panel {
  padding: 20px;
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.09);
}

.intro-panel h2,
.panel-header h2 {
  margin: 0 0 10px;
  font-size: 1.12rem;
  color: #161616;
}

.intro-panel h2 {
  color: #ffffff;
}

.intro-panel ul {
  margin: 0;
  padding-left: 18px;
  line-height: 1.72;
  color: var(--text-soft);
}

.primary-btn,
.secondary-btn,
.control-input {
  font-family: inherit;
}

.primary-btn,
.secondary-btn {
  appearance: none;
  border-radius: 999px;
  padding: 13px 20px;
  font-size: 0.94rem;
  font-weight: 800;
  cursor: pointer;
  transition: transform 0.18s ease, background 0.18s ease, border-color 0.18s ease;
}

.primary-btn {
  border: 0;
  background: var(--gold);
  color: #0d2440;
  box-shadow: 0 14px 26px rgba(255, 213, 79, 0.18);
}

.primary-btn:hover,
.secondary-btn:hover {
  transform: translateY(-2px);
}

.primary-btn:hover {
  background: #ffe082;
}

.compact {
  padding-inline: 18px;
}

.secondary-btn {
  border: 1px solid rgba(10, 23, 38, 0.1);
  background: #ffffff;
  color: #1f2f45;
}

.lab-screen {
  display: none;
}

.lab-screen.active {
  display: block;
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  padding: 24px;
  margin-bottom: 16px;
  border-radius: 28px;
  background: var(--panel-dark);
  border: 1px solid rgba(255, 255, 255, 0.12);
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.topbar h1 {
  font-size: clamp(2rem, 4vw, 2.8rem);
}

.status-pill {
  padding: 10px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.88rem;
  font-weight: 700;
}

.lab-layout {
  display: grid;
  grid-template-columns: 340px minmax(0, 1fr);
  gap: 16px;
}

.control-column,
.visual-column {
  display: grid;
  gap: 16px;
}

.panel,
.metric-card {
  border-radius: var(--radius);
}

.panel {
  padding: 20px;
  background: var(--panel-light);
  border: 1px solid var(--line);
  box-shadow: 0 20px 44px rgba(10, 23, 38, 0.08);
}

.panel-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: flex-start;
  margin-bottom: 14px;
}

.panel-copy,
.control-note,
.glossary-list p,
.insight-text {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  line-height: 1.7;
  color: var(--body);
}

.control-group {
  display: grid;
  gap: 8px;
  margin-bottom: 16px;
}

.control-label {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.9rem;
  font-weight: 700;
  color: #1f2f45;
}

.control-input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 16px;
  border: 1px solid rgba(10, 23, 38, 0.1);
  background: #f8fbff;
  color: #1f2f45;
  font-size: 0.95rem;
}

.slider {
  width: 100%;
}

.button-row {
  display: flex;
  gap: 10px;
  margin-bottom: 10px;
}

.button-row > * {
  flex: 1;
}

.control-note {
  margin-top: 10px;
  font-size: 0.9rem;
}

.mission-list,
.glossary-list {
  display: grid;
  gap: 10px;
}

.mission-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.mission-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 10px;
  padding: 12px 14px;
  border-radius: 18px;
  background: #f8fbff;
  border: 1px solid rgba(0, 94, 162, 0.08);
}

.mission-item.done {
  background: #eef8f1;
  border-color: rgba(19, 111, 60, 0.16);
}

.mission-mark {
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: #edf4ff;
  color: #005EA2;
  font-size: 0.82rem;
  font-weight: 800;
}

.mission-item.done .mission-mark {
  background: #dff4e6;
  color: #136f3c;
}

.mission-item strong,
.glossary-list strong,
.completion-box strong {
  display: block;
  margin-bottom: 4px;
  color: #161616;
}

.mission-item span,
.glossary-list p,
.completion-box span {
  font-size: 0.9rem;
}

.completion-box {
  margin-top: 12px;
  padding: 14px 16px;
  border-radius: 18px;
  background: #f7f1e5;
  border: 1px solid rgba(122, 90, 35, 0.12);
  color: #6c5428;
}

.hidden {
  display: none;
}

.metric-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.metric-card {
  padding: 16px;
  background: var(--panel-dark);
  border: 1px solid rgba(255, 255, 255, 0.12);
  box-shadow: var(--shadow);
}

.metric-card span {
  display: block;
  margin-bottom: 10px;
  font-size: 0.82rem;
  color: var(--text-soft);
}

.metric-card strong {
  font-size: 1.2rem;
}

.plot-panel canvas,
.loss-panel canvas,
.network-panel svg {
  width: 100%;
  border-radius: 18px;
  background: #f8fbff;
}

.plot-panel canvas,
.loss-panel canvas {
  border: 1px solid rgba(0, 94, 162, 0.08);
}

.visual-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.insight-text {
  font-size: 1rem;
}

@media (max-width: 1100px) {
  .lab-layout {
    grid-template-columns: 1fr;
  }

  .metric-strip,
  .visual-row,
  .intro-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .app-shell {
    padding: 16px 12px 28px;
  }

  .intro-card,
  .topbar,
  .panel,
  .metric-card {
    padding: 16px;
  }

  .topbar {
    flex-direction: column;
    align-items: stretch;
  }

  .metric-strip,
  .visual-row,
  .intro-grid,
  .button-row {
    grid-template-columns: 1fr;
    flex-direction: column;
  }
}