/* ================= DESIGN SYSTEM VARIABLES ================= */
:root {
  --font-display: 'Outfit', 'Noto Sans KR', -apple-system, sans-serif;
  --font-body: 'Noto Sans KR', -apple-system, sans-serif;
  --font-mono: 'Fira Code', 'Consolas', monospace;

  /* Color Palette - Light Mode */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-glass: rgba(255, 255, 255, 0.75);
  --border-glass: rgba(255, 255, 255, 0.5);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;
  --border-color: rgba(15, 23, 42, 0.08);
  --grid-line: rgba(15, 23, 42, 0.04);
  
  --accent-copper: #d97706;
  --accent-copper-hover: #b45309;
  --accent-copper-soft: rgba(217, 119, 6, 0.08);
  
  --led-glow: #ef4444;
  --led-off: rgba(15, 23, 42, 0.08);
  --led-glow-shadow: rgba(239, 68, 68, 0.4);
  
  --shadow-sm: 0 2px 8px -1px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 12px 30px -4px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 40px -4px rgba(0, 0, 0, 0.12);
  --glass-blur: blur(12px);
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

:root[data-theme="dark"] {
  /* Color Palette - Dark Mode */
  --bg-primary: #0b0f17;
  --bg-secondary: #121824;
  --bg-tertiary: #1a2333;
  --bg-glass: rgba(18, 24, 36, 0.7);
  --border-glass: rgba(255, 255, 255, 0.05);
  
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-tertiary: #64748b;
  --border-color: rgba(255, 255, 255, 0.08);
  --grid-line: rgba(255, 255, 255, 0.04);
  
  --accent-copper: #fbbf24;
  --accent-copper-hover: #f59e0b;
  --accent-copper-soft: rgba(251, 191, 36, 0.12);
  
  --led-glow: #ff4a4a;
  --led-off: rgba(255, 255, 255, 0.08);
  --led-glow-shadow: rgba(255, 74, 74, 0.5);
  
  --shadow-sm: 0 2px 10px -2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 16px 36px -4px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 24px 48px -4px rgba(0, 0, 0, 0.7);
}

/* ================= BASIC SETUP ================= */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  color-scheme: light dark;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.4s ease, color 0.4s ease;
}

.wrap {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 5vw, 3rem);
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-smooth);
}

button, input, textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

/* Glassmorphism utility */
.glass {
  background: var(--bg-glass);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-glass);
}

/* Eyebrow style */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-copper);
  margin-bottom: 0.75rem;
}

.badge-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-copper);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--accent-copper);
}

/* ================= TOASTS ================= */
#toastContainer {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  min-width: 300px;
  max-width: 420px;
  background: var(--bg-secondary);
  border-left: 4px solid var(--accent-copper);
  box-shadow: var(--shadow-lg);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  animation: toastIn 0.35s cubic-bezier(0.16, 1, 0.3, 1), toastOut 0.4s ease 3.6s forwards;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(-20px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes toastOut {
  to { opacity: 0; transform: translateY(-20px) scale(0.95); }
}

/* ================= NAVIGATION ================= */
.nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.4s ease;
}

.nav .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--bg-tertiary);
  border-radius: 10px;
  border: 1px solid var(--border-color);
}

.brand-mark {
  width: 22px;
  height: 22px;
}

.led-dot {
  fill: var(--led-off);
  transition: fill 0.3s;
}

.led-1 { fill: var(--led-glow); filter: drop-shadow(0 0 2px var(--led-glow)); }
.led-3 { fill: var(--led-glow); }
.led-5 { fill: var(--led-glow); }

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-word {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.3rem;
  letter-spacing: -0.02em;
}

.brand-sub {
  font-size: 0.7rem;
  color: var(--text-tertiary);
  font-weight: 500;
  margin-top: -2px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.nav-link:hover {
  color: var(--text-primary);
}

/* ================= BUTTONS ================= */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.6rem 1.2rem;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background-color: var(--accent-copper);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(217, 119, 6, 0.2);
}

.btn-primary:hover {
  background-color: var(--accent-copper-hover);
  box-shadow: 0 6px 16px rgba(217, 119, 6, 0.3);
}

.btn-ghost {
  background-color: transparent;
  border-color: var(--border-color);
  color: var(--text-primary);
}

.btn-ghost:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--text-tertiary);
}

.btn-link {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-weight: 600;
  cursor: pointer;
  text-decoration: underline;
  padding: 0.5rem;
}

.btn-link:hover {
  color: var(--text-primary);
}

.btn-lg {
  padding: 0.8rem 1.6rem;
  font-size: 1rem;
  border-radius: 12px;
}

.btn-sm {
  padding: 0.4rem 0.8rem;
  font-size: 0.8rem;
  border-radius: 8px;
}

.w-100 {
  width: 100%;
}

/* Theme Switcher Button */
.btn-theme {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  background: transparent;
  cursor: pointer;
  color: var(--text-secondary);
  transition: var(--transition-smooth);
}

.btn-theme:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-theme .sun-icon { display: block; width: 20px; height: 20px; }
.btn-theme .moon-icon { display: none; width: 20px; height: 20px; }

:root[data-theme="dark"] .btn-theme .sun-icon { display: none; }
:root[data-theme="dark"] .btn-theme .moon-icon { display: block; }

/* ================= HERO SECTION ================= */
.hero {
  position: relative;
  padding: 5rem 0 6rem;
  overflow: hidden;
  background-image: 
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 40px 40px;
  background-position: center;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 4rem;
  align-items: center;
}

.hero-content h1 {
  font-size: clamp(2.5rem, 5vw, 4.2rem);
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 1.5rem;
}

.hero-content h1 em {
  font-style: normal;
  color: var(--accent-copper);
  position: relative;
  display: inline-block;
}

.hero-content h1 em::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 0;
  width: 100%;
  height: 8px;
  background: var(--accent-copper-soft);
  z-index: -1;
}

.hero-content .lede {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 48ch;
  margin-bottom: 2.5rem;
}

.hero-ctas {
  display: flex;
  gap: 1rem;
}

/* Hero Matrix Visual */
.hero-visual {
  display: flex;
  justify-content: center;
}

.hero-stage {
  border-radius: 24px;
  padding: 2.5rem;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  max-width: 320px;
  width: 100%;
}

.stage-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.dot-live {
  width: 8px;
  height: 8px;
  background-color: var(--led-glow);
  border-radius: 50%;
  animation: live-pulse 1.8s ease-in-out infinite;
}

@keyframes live-pulse {
  0%, 100% { opacity: 0.2; transform: scale(0.9); }
  50% { opacity: 1; transform: scale(1.1); box-shadow: 0 0 10px var(--led-glow); }
}

.hero-stage-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.canvas-wrap {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: 18px;
}

/* ================= SECTION COMMON ================= */
.section {
  padding: 6rem 0;
}

.section-head {
  max-width: 680px;
  margin-bottom: 4rem;
}

.section-head h2 {
  font-size: clamp(2rem, 3.5vw, 2.6rem);
  letter-spacing: -0.02em;
  margin-top: 0.5rem;
}

.section-head p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-top: 1rem;
}

.section-alt {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

/* ================= STEPS SECTION ================= */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.step-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 2.5rem 2rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-smooth);
}

.step-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent-copper);
}

.step-icon-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background-color: var(--accent-copper-soft);
  color: var(--accent-copper);
  margin-bottom: 1.5rem;
}

.step-number {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.25rem;
}

.step-card h3 {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.step-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ================= GALLERY SECTION ================= */
.filter-row {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-bottom: 3rem;
}

.chip {
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.5rem 1.1rem;
  border-radius: 99px;
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.chip:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.chip[aria-pressed="true"] {
  background: var(--accent-copper);
  color: #ffffff;
  border-color: var(--accent-copper);
  box-shadow: 0 4px 10px rgba(217, 119, 6, 0.2);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  transition: var(--transition-smooth);
  height: 100%;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent-copper);
  background: var(--bg-secondary);
}

.card-top {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--bg-tertiary);
  border-radius: 12px;
  padding: 4px;
  flex-shrink: 0;
  border: 1px solid var(--border-color);
}

.card-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.tag {
  font-size: 0.72rem;
  font-weight: 700;
  font-family: var(--font-display);
  padding: 0.25rem 0.6rem;
  border-radius: 6px;
  background: var(--accent-copper-soft);
  color: var(--accent-copper);
}

.tag.grade {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.card h3 {
  font-size: 1.2rem;
  margin-top: 0.25rem;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.92rem;
  flex-grow: 1;
}

.card-unit {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
  margin-top: 0.5rem;
}

.card-links {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 0.5rem;
}

.card-link-makecode {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-tertiary);
}

.card-link-makecode:hover {
  color: var(--accent-copper);
}

/* ================= GRAPH SCOPE DEMO ================= */
.scope {
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.scope-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.75rem;
  border-bottom: 1px solid var(--border-color);
  flex-wrap: wrap;
  gap: 1rem;
}

.tabs {
  display: flex;
  gap: 0.4rem;
  background: var(--bg-tertiary);
  padding: 0.3rem;
  border-radius: 10px;
}

.tab {
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: 7px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.tab[aria-selected="true"] {
  background: var(--bg-secondary);
  color: var(--text-primary);
  box-shadow: var(--shadow-sm);
}

.serial-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.serial-status {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-secondary);
}

.serial-status.is-live {
  color: var(--led-glow);
  font-weight: bold;
}

.scope-body {
  display: grid;
  grid-template-columns: 1fr 220px;
  background: var(--bg-secondary);
}

.scope-chart-wrap {
  padding: 2rem;
  overflow-x: auto;
  border-right: 1px solid var(--border-color);
}

.scope-chart-wrap canvas {
  display: block;
  max-width: 100%;
}

.scope-readout {
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}

.readout-label {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin-bottom: 0.5rem;
}

.readout-value-container {
  display: flex;
  align-items: baseline;
  justify-content: center;
}

.readout-value {
  font-family: var(--font-mono);
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--led-glow);
  text-shadow: 0 0 16px var(--led-glow-shadow);
  line-height: 1;
}

.readout-unit {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-left: 0.25rem;
}

.scope-foot {
  padding: 1rem 1.75rem;
  background: var(--bg-tertiary);
  border-top: 1px solid var(--border-color);
}

.scope-note {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* ================= TEACHER RESOURCES ================= */
.resource-container {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.resource-list-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.resource-item-card {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  padding: 1.5rem;
  transition: var(--transition-smooth);
}

.resource-item-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-sm);
  border-color: var(--accent-copper);
}

.resource-icon {
  font-size: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 60px;
  height: 60px;
  background: var(--bg-tertiary);
  border-radius: 14px;
}

.resource-info {
  flex-grow: 1;
}

.resource-info h3 {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.resource-info p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* COLLAPSIBLE RESOURCE PANELS */
.lesson-panel {
  border-radius: 20px;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1rem;
}

.lesson-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  overflow: hidden;
  transition: var(--transition-smooth);
}

.lesson-item-head {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  background: transparent;
  border: none;
  cursor: pointer;
  font-weight: 700;
  color: var(--text-primary);
  text-align: left;
}

.lesson-item-title {
  font-size: 1.05rem;
  color: var(--text-primary);
}

.lesson-item-meta {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.lesson-item-head::after {
  content: '↓';
  font-size: 1.2rem;
  color: var(--accent-copper);
  transition: transform 0.3s;
}

.lesson-item.open {
  border-color: var(--accent-copper);
}

.lesson-item.open .lesson-item-head::after {
  transform: rotate(180deg);
}

.lesson-item-body {
  display: none;
  padding: 0 1.5rem 1.5rem;
  border-top: 1px solid var(--border-color);
}

.lesson-item.open .lesson-item-body {
  display: block;
  padding-top: 1.5rem;
}

.lesson-block {
  margin-bottom: 1.25rem;
}

.lesson-block:last-child {
  margin-bottom: 0;
}

.lesson-label {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-copper);
  margin-bottom: 0.5rem;
}

.lesson-block p {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.lesson-block ul, .lesson-block ol {
  padding-left: 1.25rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.lesson-block li {
  margin-bottom: 0.25rem;
}

/* Tables inside lessons */
.lesson-flow-wrap, .table-scroll-wrapper {
  overflow-x: auto;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  margin-top: 0.5rem;
}

.lesson-flow {
  width: 100%;
  min-width: 500px;
  border-collapse: collapse;
  font-size: 0.88rem;
}

.lesson-flow td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.lesson-flow tr:last-child td {
  border-bottom: none;
}

.lesson-flow td:first-child {
  font-weight: 700;
  color: var(--text-primary);
  width: 80px;
}

.lesson-flow td:nth-child(2) {
  font-family: var(--font-mono);
  color: var(--text-tertiary);
  width: 60px;
}

/* Student dashboard worksheets input elements */
.worksheet-input {
  width: 100%;
  padding: 0.75rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: var(--transition-smooth);
  resize: vertical;
}

.worksheet-input:focus {
  outline: none;
  border-color: var(--accent-copper);
  box-shadow: 0 0 0 3px var(--accent-copper-soft);
}

.worksheet-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.worksheet-table th, .worksheet-table td {
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  text-align: center;
}

.worksheet-table th {
  background-color: var(--bg-tertiary);
  font-weight: 700;
}

.worksheet-table input {
  width: 100%;
  border: none;
  background: transparent;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.95rem;
}

.worksheet-table input:focus {
  outline: none;
  background-color: var(--bg-tertiary);
  border-radius: 4px;
}

/* CODE PANEL STYLING */
.code-panel {
  border-radius: 20px;
  overflow: hidden;
  margin-top: 1rem;
}

.code-panel-tabs-container {
  padding: 1.25rem 1.5rem 0.5rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.code-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.5rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  font-weight: 600;
  font-size: 0.95rem;
}

.code-block-wrapper {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
}

.code-block {
  margin: 0;
  padding: 1.5rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.7;
}

.code-panel-note {
  padding: 1rem 1.5rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* OFFICIAL TOOLS GRID */
.official-tools-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}

.tool-link-card {
  border-radius: 18px;
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-smooth);
}

.tool-link-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent-copper);
}

.tool-title {
  font-weight: 700;
  font-size: 1.05rem;
  margin-bottom: 0.5rem;
  color: var(--accent-copper);
}

.tool-link-card p {
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ================= FOOTER ================= */
footer {
  border-top: 1px solid var(--border-color);
  padding: 3rem 0;
  background: var(--bg-secondary);
}

.footer-wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--text-tertiary);
}

/* ================= VIEW SWITCHING & LOGIN COMMON ================= */
.view[hidden] {
  display: none !important;
}

.login-screen {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 3rem 1.5rem;
  background-image: 
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 40px 40px;
}

.login-topbar {
  position: absolute;
  top: 2rem;
  left: 2rem;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.login-topbar:hover {
  color: var(--text-primary);
}

.login-card {
  width: 100%;
  max-width: 480px;
  border-radius: 28px;
  padding: 3rem 2.5rem 2.5rem;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border-glass);
}

.login-dots {
  display: flex;
  justify-content: center;
  gap: 0.6rem;
  margin-bottom: 2rem;
}

.login-dots .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border-color);
  transition: var(--transition-smooth);
}

.login-dots .dot.active {
  background: var(--accent-copper);
  box-shadow: 0 0 8px var(--accent-copper);
}

.login-step {
  display: none;
}

.login-step.active {
  display: block;
  animation: stepIn 0.4s ease;
}

@keyframes stepIn {
  from { opacity: 0; transform: translateX(10px); }
  to { opacity: 1; transform: translateX(0); }
}

.login-card h2 {
  font-size: 1.5rem;
  margin-top: 0.5rem;
  margin-bottom: 0.5rem;
}

.login-card p.hint {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
}

/* Step 1 input code */
.code-input {
  width: 100%;
  font-family: var(--font-mono);
  font-size: 1.8rem;
  letter-spacing: 0.25em;
  text-align: center;
  text-transform: uppercase;
  padding: 0.8rem;
  border-radius: 12px;
  border: 2px solid var(--border-color);
  background: var(--bg-tertiary);
  transition: var(--transition-smooth);
}

.code-input:focus {
  outline: none;
  border-color: var(--accent-copper);
  background: var(--bg-secondary);
  box-shadow: 0 0 0 4px var(--accent-copper-soft);
}

/* Step 2 students names grid */
.name-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(85px, 1fr));
  gap: 0.6rem;
  margin-bottom: 2rem;
  max-height: 280px;
  overflow-y: auto;
  padding: 0.25rem;
}

.name-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  background: transparent;
  border: 2px solid transparent;
  border-radius: 16px;
  padding: 0.75rem 0.25rem;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  transition: var(--transition-smooth);
}

.name-btn:hover {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
}

.avatar-circle {
  width: 54px;
  height: 54px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 800;
  box-shadow: var(--shadow-sm);
}

/* Step 3 password pattern */
.password-grid {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.password-tile {
  position: relative;
  width: 66px;
  height: 66px;
  border-radius: 16px;
  border: 2px solid var(--border-color);
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.password-tile:hover {
  border-color: var(--text-tertiary);
}

.password-tile.picked {
  border-color: var(--accent-copper);
  background: var(--bg-secondary);
  box-shadow: 0 4px 12px var(--accent-copper-soft);
}

.password-tile .badge {
  position: absolute;
  top: -8px;
  right: -8px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent-copper);
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.login-back {
  width: 100%;
  margin-top: 0.75rem;
}

/* Card shake on wrong pwd */
.login-card.shake {
  animation: cardshake 0.4s ease;
}

@keyframes cardshake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-8px); }
  40%, 80% { transform: translateX(8px); }
}

/* ================= TEACHER SETUP / DASHBOARD ================= */
.teacher-card {
  max-width: 640px;
}

.form-group {
  margin-bottom: 1.5rem;
}

.field-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.text-input {
  width: 100%;
  padding: 0.75rem 1rem;
  border-radius: 10px;
  border: 2px solid var(--border-color);
  background: var(--bg-tertiary);
  transition: var(--transition-smooth);
}

.text-input:focus {
  outline: none;
  border-color: var(--accent-copper);
  background: var(--bg-secondary);
  box-shadow: 0 0 0 3px var(--accent-copper-soft);
}

.teacher-students {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1rem;
}

.teacher-student-row {
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1.25rem;
  background: var(--bg-tertiary);
}

.teacher-student-row-head {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.teacher-student-row-head .text-input {
  flex-grow: 1;
}

.row-remove {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  cursor: pointer;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
}

.row-remove:hover {
  border-color: var(--led-glow);
  color: var(--led-glow);
  background: var(--led-glow-shadow);
}

.password-grid.mini {
  justify-content: flex-start;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.password-grid.mini .password-tile {
  width: 44px;
  height: 44px;
  border-radius: 10px;
}

.password-grid.mini .password-tile canvas {
  width: 28px;
  height: 28px;
}

.row-hint {
  font-size: 0.78rem;
  color: var(--text-tertiary);
  margin-top: 0.5rem;
}

.teacher-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.teacher-actions .btn {
  flex: 1;
}

.teacher-welcome-email {
  font-size: 1.1rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.teacher-dash-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.5rem;
  margin-bottom: 1.5rem;
}

.form-section-title {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
  margin-top: 1rem;
}

.success-banner {
  background: rgba(16, 185, 129, 0.1);
  color: #10b981;
  border: 1px solid rgba(16, 185, 129, 0.2);
  padding: 0.75rem;
  border-radius: 10px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 1.5rem;
}

.result-code {
  font-family: var(--font-mono);
  color: var(--accent-copper);
  letter-spacing: 0.1em;
}

.error-msg {
  color: var(--led-glow);
  font-size: 0.85rem;
  font-weight: 600;
  min-height: 1.5em;
  margin-top: 0.5rem;
}

/* ================= EXPERIMENT DETAIL VIEW ================= */
.info-blocks-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-top: 1.25rem;
}

.block-content {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.block-content.warning {
  color: var(--led-glow);
}

.block-steps {
  padding-left: 1.5rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.block-steps li {
  margin-bottom: 0.5rem;
}

/* ================= STUDENT DASHBOARD ================= */
.dashboard-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.dashboard-section-title {
  font-size: 1.3rem;
  margin-bottom: 1rem;
}

.record-form-card {
  border-radius: 24px;
  padding: 2.5rem;
  box-shadow: var(--shadow-md);
  margin-top: 1.5rem;
}

.form-back-header {
  margin-bottom: 1.5rem;
}

.exp-form-meta {
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1rem;
}

.dash-question-text {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.sparkline-wrapper {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 0.75rem;
}

.sparkline-wrapper canvas {
  display: block;
}

/* ================= RESPONSIVE ADJUSTMENTS ================= */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  .hero-visual {
    justify-content: flex-start;
  }
  .steps-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .official-tools-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .resource-list-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .nav-links a:not(.btn) {
    display: none;
  }
  .scope-body {
    grid-template-columns: 1fr;
  }
  .scope-chart-wrap {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  .info-blocks-grid {
    grid-template-columns: 1fr;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
  .official-tools-grid {
    grid-template-columns: 1fr;
  }
}

/* Reveal transition animation triggers */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1), transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .dot-live {
    animation: none;
  }
}