:root {
  --bg: #020c02;
  --bg2: #071207;
  --bg3: #0b1c0b;
  --bg4: #0f260f;
  --green: #00ff41;
  --green2: #00cc33;
  --green-dim: #005511;
  --cyan: #00ffff;
  --yellow: #ffe033;
  --orange: #ff8800;
  --red: #ff2255;
  --white: #d4ffd4;
  --gray: #4a7a4a;
  --font-pixel: 'Press Start 2P', monospace;
  --font-mono: 'Share Tech Mono', monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--green);
  font-family: var(--font-pixel);
  font-size: 10px;
  line-height: 1.8;
  min-height: 100vh;
  overflow-x: hidden;
  cursor: default;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 3px,
    rgba(0,0,0,0.12) 3px,
    rgba(0,0,0,0.12) 4px
  );
  pointer-events: none;
  z-index: 10000;
}

#matrix-canvas {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  opacity: 0.12;
  pointer-events: none;
  z-index: 0;
}

::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb { background: var(--green-dim); border: 1px solid var(--green); }

.glow { text-shadow: 0 0 10px var(--green), 0 0 20px var(--green2); }
.glow-cyan { text-shadow: 0 0 10px var(--cyan), 0 0 20px #0088ff; }
.glow-yellow { text-shadow: 0 0 10px var(--yellow), 0 0 20px #ff8800; }
.pixel-border {
  border: 3px solid var(--green);
  box-shadow: 0 0 8px var(--green-dim), inset 0 0 8px rgba(0,255,65,0.05);
}
.pixel-border-cyan {
  border: 3px solid var(--cyan);
  box-shadow: 0 0 8px rgba(0,255,255,0.3);
}
.pixel-border-yellow {
  border: 3px solid var(--yellow);
  box-shadow: 0 0 8px rgba(255,224,51,0.3);
}
.hidden { display: none !important; }

nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(2,12,2,0.95);
  border-bottom: 3px solid var(--green);
  box-shadow: 0 0 20px rgba(0,255,65,0.2);
  padding: 0 20px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  backdrop-filter: blur(10px);
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  text-decoration: none;
}
.nav-logo-text {
  font-size: 14px;
  color: var(--yellow);
  text-shadow: 0 0 10px var(--yellow), 0 0 20px #ff8800;
  letter-spacing: 2px;
}
.nav-logo-sub { font-size: 7px; color: var(--green); letter-spacing: 1px; }
.nav-links { display: flex; gap: 6px; align-items: center; }
.nav-btn {
  background: transparent;
  border: 2px solid var(--green-dim);
  color: var(--green);
  font-family: var(--font-pixel);
  font-size: 8px;
  padding: 6px 10px;
  cursor: pointer;
  transition: all 0.15s;
  letter-spacing: 1px;
}
.nav-btn:hover, .nav-btn.active {
  border-color: var(--green);
  background: rgba(0,255,65,0.1);
  box-shadow: 0 0 8px var(--green-dim);
  color: var(--yellow);
}
.xp-bar-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 8px;
  color: var(--cyan);
}
.xp-track {
  width: 80px;
  height: 10px;
  background: var(--bg3);
  border: 2px solid var(--cyan);
}
.xp-fill {
  height: 100%;
  background: var(--cyan);
  box-shadow: 0 0 6px var(--cyan);
  transition: width 0.5s;
}

.view {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  padding-top: 60px;
}

#view-home {
  display: flex;
  flex-direction: column;
}
.hero {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  min-height: calc(100vh - 60px);
  padding: 40px 20px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero-grid-bg {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(0,255,65,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,255,65,0.04) 1px, transparent 1px);
  background-size: 40px 40px;
}
.hero-chick-wrap {
  position: relative;
  margin-bottom: 20px;
}
#hero-chick-canvas {
  image-rendering: pixelated;
}
.hero-badge {
  position: absolute;
  top: -8px;
  right: -15px;
  background: var(--red);
  color: #fff;
  font-size: 7px;
  padding: 3px 6px;
  border: 2px solid #ff6688;
  animation: badge-blink 1.5s infinite;
}
@keyframes badge-blink {
  0%,100% { opacity: 1; }
  50% { opacity: 0.4; }
}
.hero-title {
  font-size: clamp(18px, 5vw, 36px);
  color: var(--yellow);
  text-shadow: 0 0 15px var(--yellow), 0 0 30px #ff8800, 4px 4px 0 #996600;
  margin-bottom: 10px;
  letter-spacing: 4px;
  line-height: 1.4;
}
.hero-subtitle {
  font-size: clamp(8px, 2vw, 12px);
  color: var(--cyan);
  text-shadow: 0 0 10px var(--cyan);
  margin-bottom: 8px;
  letter-spacing: 2px;
}
.hero-tagline {
  font-size: 9px;
  color: var(--green);
  margin-bottom: 30px;
  max-width: 500px;
  line-height: 2;
}
.hero-terminal {
  background: var(--bg2);
  border: 3px solid var(--green);
  box-shadow: 0 0 20px rgba(0,255,65,0.2);
  padding: 15px 20px;
  margin-bottom: 30px;
  max-width: 500px;
  width: 100%;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 13px;
}
.terminal-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--green-dim);
}
.t-dot { width: 10px; height: 10px; border: 2px solid; }
.t-dot-r { border-color: var(--red); background: var(--red); }
.t-dot-y { border-color: var(--yellow); background: var(--yellow); }
.t-dot-g { border-color: var(--green); background: var(--green); }
.terminal-title { font-family: var(--font-pixel); font-size: 8px; color: var(--gray); }
.terminal-line { color: var(--green); }
.terminal-prompt { color: var(--yellow); }
.terminal-output { color: var(--cyan); }
#typed-text { color: var(--green); }
.cursor-blink {
  display: inline-block;
  width: 8px;
  height: 14px;
  background: var(--green);
  animation: cursor-blink 1s infinite;
  vertical-align: middle;
}
@keyframes cursor-blink {
  0%,49% { opacity: 1; }
  50%,100% { opacity: 0; }
}
.hero-cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}
.btn-primary {
  background: var(--green);
  color: var(--bg);
  border: 3px solid var(--green);
  font-family: var(--font-pixel);
  font-size: 10px;
  padding: 12px 20px;
  cursor: pointer;
  letter-spacing: 1px;
  box-shadow: 4px 4px 0 var(--green2), 0 0 15px rgba(0,255,65,0.4);
  transition: all 0.1s;
}
.btn-primary:hover {
  transform: translate(-2px,-2px);
  box-shadow: 6px 6px 0 var(--green2), 0 0 25px rgba(0,255,65,0.6);
}
.btn-primary:active { transform: translate(2px,2px); box-shadow: 2px 2px 0 var(--green2); }
.btn-secondary {
  background: transparent;
  color: var(--cyan);
  border: 3px solid var(--cyan);
  font-family: var(--font-pixel);
  font-size: 10px;
  padding: 12px 20px;
  cursor: pointer;
  letter-spacing: 1px;
  box-shadow: 4px 4px 0 #005566;
  transition: all 0.1s;
}
.btn-secondary:hover {
  background: rgba(0,255,255,0.1);
  transform: translate(-2px,-2px);
  box-shadow: 6px 6px 0 #005566;
}

.features-section {
  padding: 60px 20px;
  background: var(--bg2);
  border-top: 3px solid var(--green-dim);
}
.section-title {
  text-align: center;
  font-size: 14px;
  color: var(--cyan);
  text-shadow: 0 0 10px var(--cyan);
  margin-bottom: 40px;
  letter-spacing: 3px;
}
.section-title span { color: var(--yellow); }
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}
.feature-card {
  background: var(--bg3);
  border: 2px solid var(--green-dim);
  padding: 20px;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
}
.feature-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px;
  height: 100%;
  background: var(--green);
}
.feature-card:hover {
  border-color: var(--green);
  box-shadow: 0 0 15px rgba(0,255,65,0.2);
  transform: translateY(-3px);
}
.feature-icon { font-size: 24px; margin-bottom: 12px; display: block; }
.feature-title { font-size: 10px; color: var(--yellow); margin-bottom: 8px; }
.feature-desc { font-family: var(--font-mono); font-size: 12px; color: var(--gray); line-height: 1.6; }

.languages-section {
  padding: 60px 20px;
}
.lang-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 15px;
  max-width: 900px;
  margin: 0 auto;
}
.lang-card {
  background: var(--bg3);
  border: 2px solid var(--green-dim);
  padding: 15px;
  cursor: pointer;
  transition: all 0.15s;
  text-align: center;
  position: relative;
}
.lang-card:hover {
  border-color: var(--green);
  background: var(--bg4);
  box-shadow: 0 0 15px rgba(0,255,65,0.2);
  transform: translate(-2px,-2px);
}
.lang-card-icon {
  width: 32px;
  height: 32px;
  object-fit: contain;
  margin: 0 auto 8px auto;
  display: block;
}
.lang-card-name { font-size: 9px; color: var(--green); display: block; margin-bottom: 4px; }
.lang-card-diff {
  font-size: 7px;
  padding: 2px 5px;
  border: 1px solid;
  display: inline-block;
}
.diff-easy { color: var(--green); border-color: var(--green); }
.diff-med { color: var(--yellow); border-color: var(--yellow); }
.diff-hard { color: var(--red); border-color: var(--red); }
.lang-coming {
  position: absolute;
  top: 5px; right: 5px;
  font-size: 6px;
  color: var(--gray);
  border: 1px solid var(--gray);
  padding: 1px 3px;
}

#view-courses { padding: 80px 20px 40px; }
.courses-header {
  text-align: center;
  margin-bottom: 40px;
}
.course-back-btn {
  background: transparent;
  border: 2px solid var(--green-dim);
  color: var(--green);
  font-family: var(--font-pixel);
  font-size: 8px;
  padding: 6px 12px;
  cursor: pointer;
  margin-bottom: 20px;
}
.course-back-btn:hover { border-color: var(--green); }
.course-title-big {
  font-size: 20px;
  color: var(--yellow);
  text-shadow: 0 0 10px var(--yellow);
  margin-bottom: 8px;
}
.course-meta { font-size: 8px; color: var(--gray); margin-bottom: 20px; }
.lessons-list {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.lesson-item {
  background: var(--bg2);
  border: 2px solid var(--green-dim);
  padding: 15px 20px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 15px;
  transition: all 0.15s;
}
.lesson-item:hover {
  border-color: var(--green);
  background: var(--bg3);
  transform: translateX(5px);
}
.lesson-item.completed { border-color: var(--green2); }
.lesson-item.locked { opacity: 0.4; cursor: not-allowed; }
.lesson-num {
  background: var(--green-dim);
  color: var(--green);
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  flex-shrink: 0;
  border: 2px solid var(--green);
}
.lesson-item.completed .lesson-num {
  background: var(--green);
  color: var(--bg);
}
.lesson-info { flex: 1; }
.lesson-name { font-size: 10px; color: var(--green); margin-bottom: 4px; }
.lesson-desc { font-family: var(--font-mono); font-size: 12px; color: var(--gray); }
.lesson-xp { font-size: 8px; color: var(--cyan); }

#view-lesson {
  padding: 60px 0 0;
  display: flex;
  flex-direction: column;
  height: 100vh;
}
.lesson-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 20px;
  background: var(--bg2);
  border-bottom: 2px solid var(--green-dim);
  flex-shrink: 0;
}
.lesson-breadcrumb { font-size: 8px; color: var(--gray); }
.lesson-breadcrumb span { color: var(--green); }
.lesson-progress-info { font-size: 8px; color: var(--cyan); }
.lesson-main {
  display: flex;
  flex: 1;
  overflow: hidden;
  gap: 0;
}

.theory-panel {
  width: 38%;
  min-width: 280px;
  background: var(--bg2);
  border-right: 3px solid var(--green-dim);
  overflow-y: auto;
  padding: 20px;
  flex-shrink: 0;
}
.theory-lesson-title {
  font-size: 12px;
  color: var(--yellow);
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--green-dim);
  line-height: 1.6;
}
.theory-content {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--white);
  line-height: 1.8;
}
.theory-content h3 {
  font-family: var(--font-pixel);
  font-size: 9px;
  color: var(--cyan);
  margin: 16px 0 8px;
}
.theory-content p { margin-bottom: 10px; }
.theory-content code {
  background: var(--bg4);
  color: var(--yellow);
  padding: 1px 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  border: 1px solid var(--green-dim);
}
.theory-content pre {
  background: var(--bg);
  border: 2px solid var(--green-dim);
  border-left: 4px solid var(--green);
  padding: 12px;
  margin: 10px 0;
  overflow-x: auto;
  font-size: 12px;
  color: var(--green);
  position: relative;
}
.theory-content pre .kw { color: var(--cyan); }
.theory-content pre .str { color: var(--yellow); }
.theory-content pre .cmt { color: var(--gray); }
.theory-content pre .num { color: var(--orange); }
.theory-content ul { padding-left: 15px; margin-bottom: 10px; }
.theory-content li { margin-bottom: 6px; }
.theory-content li::marker { color: var(--green); }
.theory-nav {
  display: flex;
  gap: 8px;
  margin-top: 20px;
  padding-top: 15px;
  border-top: 2px solid var(--green-dim);
  flex-wrap: wrap;
}
.theory-nav button {
  background: transparent;
  border: 2px solid var(--green-dim);
  color: var(--green);
  font-family: var(--font-pixel);
  font-size: 8px;
  padding: 6px 10px;
  cursor: pointer;
  transition: all 0.15s;
}
.theory-nav button:hover { border-color: var(--green); background: rgba(0,255,65,0.1); }
.theory-nav button.active { border-color: var(--yellow); color: var(--yellow); }

.code-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}
.code-editor-wrap {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-bottom: 3px solid var(--green-dim);
}
.editor-header {
  background: var(--bg3);
  border-bottom: 2px solid var(--green-dim);
  padding: 6px 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-shrink: 0;
}
.editor-tabs { display: flex; gap: 0; }
.editor-tab {
  padding: 4px 12px;
  font-family: var(--font-pixel);
  font-size: 7px;
  background: var(--bg2);
  color: var(--gray);
  border: 1px solid var(--green-dim);
  cursor: pointer;
}
.editor-tab.active { background: var(--bg4); color: var(--green); border-color: var(--green); border-bottom-color: var(--bg4); }
.editor-actions { display: flex; gap: 6px; }
.editor-btn {
  font-family: var(--font-pixel);
  font-size: 7px;
  padding: 5px 10px;
  cursor: pointer;
  border: 2px solid;
  transition: all 0.1s;
}
.btn-run { color: var(--green); border-color: var(--green); background: rgba(0,255,65,0.1); }
.btn-run:hover { background: rgba(0,255,65,0.2); }
.btn-check { color: var(--cyan); border-color: var(--cyan); background: rgba(0,255,255,0.1); }
.btn-check:hover { background: rgba(0,255,255,0.2); }
.btn-reset { color: var(--gray); border-color: var(--gray); background: transparent; }
.btn-reset:hover { border-color: var(--red); color: var(--red); }
.btn-hint { color: var(--yellow); border-color: var(--yellow); background: rgba(255,224,51,0.1); }
.btn-hint:hover { background: rgba(255,224,51,0.2); }

.editor-body {
  display: flex;
  flex: 1;
  overflow: hidden;
}
.line-numbers {
  background: var(--bg);
  color: var(--green-dim);
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 10px 8px;
  text-align: right;
  user-select: none;
  min-width: 40px;
  border-right: 1px solid var(--green-dim);
  overflow: hidden;
  line-height: 1.6;
  white-space: pre;
}
#code-editor {
  flex: 1;
  background: var(--bg);
  color: var(--yellow);
  border: none;
  outline: none;
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 10px;
  resize: none;
  line-height: 1.6;
  caret-color: var(--green);
  tab-size: 4;
}
#code-editor::selection { background: rgba(0,255,65,0.2); }

.exercise-desc {
  background: var(--bg2);
  border: 2px solid var(--yellow);
  border-left: 4px solid var(--yellow);
  padding: 12px;
  margin: 8px;
  font-size: 9px;
  line-height: 1.8;
  color: var(--white);
  flex-shrink: 0;
}
.exercise-desc strong { color: var(--yellow); display: block; margin-bottom: 5px; }

.output-panel {
  background: var(--bg);
  border-top: 2px solid var(--green-dim);
  padding: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  min-height: 80px;
  max-height: 120px;
  overflow-y: auto;
  flex-shrink: 0;
}
.output-line { color: var(--green); margin: 2px 0; }
.output-line.err { color: var(--red); }
.output-line.ok { color: var(--cyan); }
.output-line.warn { color: var(--yellow); }

.ai-panel {
  width: 32%;
  min-width: 250px;
  max-width: 380px;
  border-left: 3px solid var(--green-dim);
  display: flex;
  flex-direction: column;
  background: var(--bg2);
  flex-shrink: 0;
}
.ai-header {
  background: var(--bg3);
  padding: 10px 15px;
  border-bottom: 2px solid var(--green-dim);
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.ai-chick-icon {
  width: 32px;
  height: 32px;
  image-rendering: pixelated;
}
.ai-header-info { flex: 1; }
.ai-name { font-size: 9px; color: var(--yellow); }
.ai-status { font-size: 7px; color: var(--green); }
.ai-status::before {
  content: '●';
  color: var(--green);
  margin-right: 4px;
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%,100% { opacity: 1; }
  50% { opacity: 0.3; }
}
.ai-messages {
  flex: 1;
  overflow-y: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.msg {
  max-width: 85%;
  padding: 8px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  position: relative;
}
.msg-bot {
  align-self: flex-start;
  background: var(--bg4);
  border: 2px solid var(--green-dim);
  border-radius: 0 4px 4px 4px;
  color: var(--white);
}
.msg-bot::before {
  content: '🐣';
  font-size: 10px;
  position: absolute;
  top: -8px;
  left: 2px;
}
.msg-user {
  align-self: flex-end;
  background: rgba(0,255,65,0.1);
  border: 2px solid var(--green);
  border-radius: 4px 0 4px 4px;
  color: var(--green);
}
.msg-user::before {
  content: '> ';
  color: var(--green2);
}
.msg code {
  background: var(--bg);
  color: var(--yellow);
  padding: 1px 4px;
  font-size: 11px;
  display: block;
  margin: 4px 0;
  border-left: 3px solid var(--green);
  padding-left: 8px;
}
.ai-input-wrap {
  display: flex;
  gap: 0;
  border-top: 2px solid var(--green-dim);
  flex-shrink: 0;
}
#ai-input {
  flex: 1;
  background: var(--bg);
  border: none;
  outline: none;
  color: var(--green);
  font-family: var(--font-mono);
  font-size: 12px;
  padding: 10px;
  resize: none;
  caret-color: var(--green);
}
#ai-input::placeholder { color: var(--green-dim); }
.ai-send-btn {
  background: var(--green-dim);
  border: none;
  border-left: 2px solid var(--green-dim);
  color: var(--green);
  font-family: var(--font-pixel);
  font-size: 8px;
  padding: 0 12px;
  cursor: pointer;
  transition: all 0.15s;
}
.ai-send-btn:hover { background: var(--green); color: var(--bg); }

#view-playground {
  padding: 60px 0 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
}
.playground-topbar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 15px;
  background: var(--bg2);
  border-bottom: 2px solid var(--green-dim);
  flex-shrink: 0;
  flex-wrap: wrap;
}
.playground-topbar span { font-size: 9px; color: var(--gray); }
.lang-select {
  background: var(--bg3);
  border: 2px solid var(--green-dim);
  color: var(--green);
  font-family: var(--font-pixel);
  font-size: 8px;
  padding: 4px 8px;
  cursor: pointer;
  outline: none;
}
.lang-select:hover, .lang-select:focus { border-color: var(--green); }
.playground-main {
  display: flex;
  flex: 1;
  overflow: hidden;
}
.playground-editor-wrap {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}
.playground-ai {
  width: 350px;
  border-left: 3px solid var(--green-dim);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
}

.pixel-corner-tl, .pixel-corner-tr, .pixel-corner-bl, .pixel-corner-br {
  position: absolute;
  width: 16px;
  height: 16px;
  pointer-events: none;
}
.corner-dec {
  position: fixed;
  z-index: 2;
  pointer-events: none;
}
.corner-tl { top: 65px; left: 5px; }
.corner-tr { top: 65px; right: 5px; }
.corner-bl { bottom: 5px; left: 5px; }
.corner-br { bottom: 5px; right: 5px; }

.typing-dots span {
  animation: typing-dot 1.2s infinite;
  font-size: 16px;
}
.typing-dots span:nth-child(2) { animation-delay: 0.2s; }
.typing-dots span:nth-child(3) { animation-delay: 0.4s; }
@keyframes typing-dot {
  0%,60%,100% { opacity: 0.2; }
  30% { opacity: 1; }
}

#xp-popup {
  position: fixed;
  top: 80px;
  right: 20px;
  background: var(--bg3);
  border: 3px solid var(--yellow);
  box-shadow: 0 0 20px rgba(255,224,51,0.4);
  padding: 12px 20px;
  font-size: 10px;
  color: var(--yellow);
  z-index: 9000;
  display: none;
  animation: slide-in 0.3s ease;
}
@keyframes slide-in {
  from { transform: translateX(100px); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

@media (max-width: 900px) {
  .lesson-main { flex-direction: column; }
  .theory-panel { width: 100%; height: 40vh; border-right: none; border-bottom: 2px solid var(--green-dim); }
  .ai-panel { width: 100%; max-width: 100%; height: 35vh; border-left: none; border-top: 2px solid var(--green-dim); }
  .playground-main { flex-direction: column; }
  .playground-ai { width: 100%; height: 300px; border-left: none; border-top: 2px solid var(--green-dim); }
}
@media (max-width: 600px) {
  nav { padding: 0 10px; }
  .nav-logo-text { font-size: 11px; }
  .nav-links { gap: 3px; }
  .nav-btn { font-size: 7px; padding: 4px 7px; }
  .hero-title { font-size: 18px; }
  .xp-bar-nav { display: none; }
}