:root {
  --bg: #0f172a;
  --surface: #111827;
  --surface-alt: #1f2937;
  --text: #f8fafc;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --accent-strong: #0ea5e9;
  --border: rgba(148, 163, 184, 0.18);
  --success: #22c55e;
  --danger: #f87171;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Inter, system-ui, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top, #111827 0%, #0b1220 45%, #020617 100%);
  line-height: 1.6;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-strong);
}

.sidebar-close-btn {
  position: absolute;
  top: 1.2rem;
  right: 1.2rem;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 999px;
  width: 32px;
  height: 32px;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
}

.sidebar-close-btn:hover {
  background: rgba(248, 113, 113, 0.12);
  color: var(--danger);
  border-color: var(--danger);
}

.sidebar {
  position: relative; /* tambahkan ini agar tombol absolute bisa di dalam sidebar */
}

.sidebar-toggle-btn {
  position: fixed;
  top: 1.2rem;
  left: 1.2rem;
  z-index: 100;
  background: var(--accent);
  color: #040617;
  border: none;
  border-radius: 999px;
  padding: 0.55rem 1rem;
  font-weight: 700;
  cursor: pointer;
  font-size: 0.9rem;
  display: none;
}

.hero {
  padding: 4rem 1.5rem;
  text-align: center;
  background: linear-gradient(180deg, rgba(14, 165, 233, 0.18), transparent 75%);
}

.hero-content {
  max-width: 900px;
  margin: 0 auto;
}

.hero h1 {
  margin: 0 0 1rem;
  font-size: clamp(2.5rem, 4vw, 4rem);
}

.hero p {
  margin: 0 0 1.75rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.95rem 1.8rem;
  border-radius: 999px;
  background: var(--accent);
  color: #040617;
  font-weight: 700;
  border: none;
  cursor: pointer;
}

.button:hover {
  opacity: 0.95;
}

.layout {
  display: grid;
  grid-template-columns: minmax(280px, 320px) 1fr;
  gap: 1.5rem;
  max-width: 1280px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

.sidebar {
  position: sticky;
  top: 1.5rem;
  height: fit-content;
}

.content {
  display: grid;
  gap: 1.5rem;
}

.section {
  margin-bottom: 0;
}

.card {
  background: rgba(15, 23, 42, 0.92);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 1.75rem;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.22);
}

.module-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.module-card {
  background: #111827;
  border: 1px solid rgba(148, 163, 184, 0.13);
  border-radius: 18px;
  padding: 1.2rem;
  min-height: 220px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.module-card h3 {
  margin: 0 0 0.75rem;
}

.module-card p {
  margin: 0 0 1rem;
  color: var(--muted);
}

.module-card button {
  align-self: flex-start;
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 999px;
  padding: 0.6rem 1rem;
  cursor: pointer;
}

.module-card button:hover {
  background: rgba(56, 189, 248, 0.12);
}

.course-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
}

.course-step-nav {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.course-step {
  padding: 0.55rem 0.85rem;
  border-radius: 999px;
  border: 1px solid rgba(56, 189, 248, 0.25);
  color: var(--accent);
  font-size: 0.9rem;
  cursor: pointer;
  background: rgba(56, 189, 248, 0.08);
}

.course-step.active {
  background: var(--accent-strong);
  color: #04111f;
  border-color: var(--accent-strong);
}

.module-block {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.module-block img {
  width: 100%;
  border-radius: 18px;
  object-fit: cover;
  min-height: 240px;
}

.module-block h3 {
  margin: 0;
}

.module-block .tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin: 1rem 0;
}

.tag {
  background: rgba(56, 189, 248, 0.12);
  color: var(--accent);
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  font-size: 0.9rem;
}

.video-grid {
  display: grid;
  gap: 1rem;
}

.video-card iframe {
  width: 100%;
  min-height: 240px;
  border: none;
  border-radius: 16px;
}

.list-card {
  background: #0f172a;
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: 18px;
  padding: 1.4rem;
}

.list-card h4 {
  margin: 0 0 0.75rem;
}

.list-card ul {
  margin: 0;
  padding-left: 1.2rem;
}

.practice-code-card {
  background: #111827;
  border: 1px solid rgba(56, 189, 248, 0.18);
  border-radius: 18px;
  padding: 1.4rem;
}

.practice-code-card h4 {
  margin: 0 0 0.8rem;
}

.practice-example {
  margin-bottom: 1.5rem;
}

.editor-label {
  margin: 0.8rem 0 0.4rem;
  color: var(--accent);
  font-size: 0.95rem;
}

.code-editor {
  width: 100%;
  min-height: 260px;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.16);
  background: #0b1121;
  color: var(--text);
  padding: 1rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.95rem;
  resize: vertical;
}

.run-code-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin: 0.85rem 0 0.65rem;
  flex-wrap: wrap;
}

.run-code-button {
  border: none;
  border-radius: 999px;
  background: var(--accent);
  color: #040617;
  padding: 0.75rem 1.3rem;
  cursor: pointer;
  font-weight: 700;
}

.code-hint {
  color: var(--muted);
  font-size: 0.95rem;
}

.code-output {
  background: #020617;
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: 16px;
  color: #d1d5db;
  padding: 1rem;
  white-space: pre-wrap;
  min-height: 90px;
}

.progress-summary {
  margin-bottom: 1rem;
  color: var(--text);
}

.progress-bar-container {
  width: 100%;
  height: 14px;
  background: rgba(148, 163, 184, 0.12);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 1.5rem;
}

.progress-bar {
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-strong));
  border-radius: 999px;
  transition: width 0.4s ease;
}

.notes-card h3 {
  margin: 0 0 0.8rem;
}

#learning-notes {
  width: 100%;
  border-radius: 18px;
  border: 1px solid rgba(148, 163, 184, 0.16);
  background: #0b1322;
  color: var(--text);
  padding: 1rem;
  min-height: 220px;
  resize: vertical;
}

.note-help {
  margin: 0.85rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.chatbot-section {
  overflow: hidden;
}

.chat-messages {
  min-height: 220px;
  background: #0b1220;
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: 18px;
  padding: 1rem;
  margin-bottom: 1rem;
  overflow-y: auto;
}

.chat-message {
  margin-bottom: 1rem;
  display: grid;
  gap: 0.35rem;
}

.chat-message.user .chat-label {
  color: var(--accent);
}

.chat-message.bot .chat-label {
  color: var(--success);
}

.chat-message .chat-bubble {
  padding: 1rem;
  border-radius: 18px;
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(56, 189, 248, 0.1);
}

.chat-input-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.75rem;
}

.chat-input-row input {
  border-radius: 18px;
  border: 1px solid rgba(148, 163, 184, 0.16);
  padding: 0.95rem 1rem;
  background: #0b1220;
  color: var(--text);
}

.quiz-card {
  background: #111827;
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: 18px;
  padding: 1.5rem;
  margin-bottom: 1rem;
}

.quiz-card h4 {
  margin: 0 0 0.75rem;
}

.quiz-card p {
  margin: 0 0 1rem;
}

.option-button {
  display: block;
  width: 100%;
  text-align: left;
  padding: 0.9rem 1rem;
  margin-bottom: 0.75rem;
  border-radius: 14px;
  border: 1px solid rgba(148, 163, 184, 0.14);
  background: #0f172a;
  color: var(--text);
  cursor: pointer;
}

.option-button:hover {
  background: rgba(56, 189, 248, 0.08);
}

.option-button.correct {
  border-color: var(--success);
  background: rgba(34, 197, 94, 0.14);
}

.option-button.wrong {
  border-color: var(--danger);
  background: rgba(248, 113, 113, 0.14);
}

.quiz-result {
  margin-top: 1rem;
  color: var(--accent);
  font-weight: 700;
}

.footer {
  text-align: center;
  padding: 2rem 1.5rem 3rem;
  color: var(--muted);
}

@media (max-width: 980px) {
  .layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .module-grid,
  .video-grid,
  .chat-input-row {
    grid-template-columns: 1fr;
  }

  .course-header {
    flex-direction: column;
  }
}