:root {
  color-scheme: dark;
  --bg: #0b1117;
  --band: #101923;
  --panel: rgba(20, 31, 43, 0.78);
  --panel-strong: #172331;
  --text: #edf6f9;
  --muted: #9db0bd;
  --border: rgba(159, 185, 198, 0.22);
  --accent: #38bdf8;
  --accent-2: #34d399;
  --danger: #fb7185;
  --shadow: 0 18px 48px rgba(0, 0, 0, 0.28);
  --radius: 8px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

body.light {
  color-scheme: light;
  --bg: #f6f8fb;
  --band: #e9eef5;
  --panel: rgba(255, 255, 255, 0.84);
  --panel-strong: #ffffff;
  --text: #13202b;
  --muted: #5c6d7a;
  --border: rgba(38, 54, 70, 0.16);
  --accent: #0f7ea8;
  --accent-2: #087f5b;
  --danger: #c24152;
  --shadow: 0 16px 42px rgba(38, 54, 70, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 10% 0%, rgba(56, 189, 248, 0.12), transparent 30%),
    linear-gradient(135deg, var(--bg), #111827 70%);
  color: var(--text);
  min-height: 100vh;
}

body.light {
  background:
    radial-gradient(circle at 10% 0%, rgba(15, 126, 168, 0.11), transparent 32%),
    linear-gradient(135deg, var(--bg), #edf3f8 70%);
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  padding: 24px 18px;
  border-right: 1px solid var(--border);
  background: rgba(10, 18, 26, 0.72);
  backdrop-filter: blur(18px);
}

body.light .sidebar {
  background: rgba(255, 255, 255, 0.72);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 26px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #031019;
  font-weight: 900;
}

.brand span,
.crumb,
.output-list dt,
.theory-card span {
  color: var(--muted);
  font-size: 0.85rem;
}

.nav {
  display: grid;
  gap: 6px;
}

.nav-item,
.theme-toggle,
.primary-btn,
.secondary-btn {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  min-height: 42px;
  padding: 0 14px;
  color: var(--text);
}

.nav-item,
.theme-toggle,
.secondary-btn {
  background: transparent;
}

.nav-item {
  text-align: left;
}

.nav-item.active,
.nav-item:hover,
.secondary-btn:hover {
  border-color: rgba(56, 189, 248, 0.55);
  background: rgba(56, 189, 248, 0.1);
}

.theme-toggle {
  width: 100%;
  margin-top: 22px;
}

.workspace {
  width: min(1480px, 100%);
  padding: 26px;
}

.topbar,
.control-panel,
.section-toolbar,
.button-row,
.result-grid,
.metric-grid {
  display: flex;
  align-items: center;
  gap: 14px;
}

.topbar {
  justify-content: space-between;
  margin-bottom: 18px;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(1.75rem, 3vw, 3rem);
  letter-spacing: 0;
}

h2 {
  font-size: 1.35rem;
  letter-spacing: 0;
}

p {
  line-height: 1.65;
  color: var(--muted);
}

.status-pill {
  border: 1px solid rgba(52, 211, 153, 0.4);
  border-radius: 999px;
  padding: 9px 12px;
  color: var(--accent-2);
  white-space: nowrap;
}

.panel,
.hero-band,
.metric-grid article,
.word-card,
.round-key,
.step-card,
.theory-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

.control-panel {
  position: sticky;
  top: 0;
  z-index: 4;
  flex-wrap: wrap;
  padding: 14px;
  margin-bottom: 20px;
}

.field-group {
  display: grid;
  gap: 6px;
  min-width: 150px;
}

.field-group.grow {
  flex: 1 1 230px;
}

label {
  color: var(--muted);
  font-size: 0.82rem;
}

input,
select {
  min-height: 42px;
  width: 100%;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0 12px;
  color: var(--text);
  background: rgba(255, 255, 255, 0.04);
  outline: none;
}

input.valid {
  border-color: #34d399;
}

input.invalid {
  border-color: #fb7185;
}

.field-hint {
  color: var(--muted);
  font-size: 0.82rem;
}

.field-hint.invalid-text {
  color: #fb7185;
}

body.light input,
body.light select {
  background: rgba(255, 255, 255, 0.78);
}

input:focus,
select:focus {
  border-color: var(--accent);
}

.primary-btn {
  border-color: transparent;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #031019;
  font-weight: 800;
}

.view {
  display: none;
}

.view.active {
  display: block;
}

.hero-band {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: 22px;
  padding: 28px;
  min-height: 280px;
  background:
    linear-gradient(135deg, rgba(56, 189, 248, 0.14), transparent),
    var(--panel);
}

.hero-band h2 {
  font-size: clamp(2rem, 4vw, 4.6rem);
  line-height: 1.04;
  max-width: 850px;
}

.metric-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: 16px;
}

.metric-grid article {
  padding: 18px;
}

.metric-grid strong {
  display: block;
  font-size: 1.6rem;
}

.metric-grid span {
  color: var(--muted);
}

.result-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.8fr);
  align-items: stretch;
}

.panel {
  padding: 20px;
}

.output-list {
  display: grid;
  gap: 8px;
}

.output-list dd {
  margin: 0 0 10px;
  overflow-wrap: anywhere;
  font-family: "Cascadia Mono", Consolas, monospace;
}

.matrix {
  display: grid;
  grid-template-columns: repeat(4, minmax(48px, 1fr));
  gap: 8px;
}

.matrix-cell {
  display: grid;
  place-items: center;
  min-height: 48px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: rgba(56, 189, 248, 0.08);
  font-family: "Cascadia Mono", Consolas, monospace;
  font-weight: 800;
}

.section-toolbar {
  justify-content: space-between;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.round-key-grid,
.word-grid,
.theory-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
}

.key-expansion-panel {
  display: grid;
  grid-template-columns: repeat(2, minmax(260px, 1fr));
  gap: 12px;
  margin-bottom: 18px;
}

.key-schedule-step {
  padding: 12px;
  margin-bottom: 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: rgba(56, 189, 248, 0.08);
}

.key-schedule-step-body p {
  margin: 6px 0;
  color: var(--text);
  font-size: 0.95rem;
}

.key-schedule-step-body strong {
  color: var(--accent);
}

.round-key,
.word-card,
.theory-card,
.step-card {
  padding: 14px;
}

.round-key code,
.word-card code {
  display: block;
  margin-top: 8px;
  color: var(--accent);
  font-family: "Cascadia Mono", Consolas, monospace;
  overflow-wrap: anywhere;
}

.search {
  margin-bottom: 14px;
}

.active-step {
  margin-bottom: 14px;
}

.active-step-grid {
  display: grid;
  grid-template-columns: minmax(260px, 0.7fr) minmax(280px, 0.3fr);
  gap: 18px;
}

.step-list {
  display: grid;
  gap: 10px;
}

.step-card summary {
  cursor: pointer;
  font-weight: 800;
}

.step-card p {
  margin: 10px 0;
}

.formula {
  display: inline-block;
  padding: 8px 10px;
  border-radius: 6px;
  background: rgba(52, 211, 153, 0.08);
  color: var(--accent-2);
  font-family: "Cascadia Mono", Consolas, monospace;
}

.test-result.pass {
  color: var(--accent-2);
}

.test-result.fail,
.error {
  color: var(--danger);
}

.toast {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 10;
  max-width: 360px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel-strong);
  box-shadow: var(--shadow);
}

@media (max-width: 960px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    height: auto;
  }

  .nav {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .hero-band,
  .result-grid,
  .active-step-grid {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 620px) {
  .workspace {
    padding: 16px;
  }

  .nav,
  .metric-grid {
    grid-template-columns: 1fr;
  }

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

  .hero-band {
    padding: 18px;
  }
}