/* 🐡 Unfish Learn — Documentation & Interactive Education Design System */

:root {
  --bg-page: #0b0f19;
  --bg-sidebar: #0f172a;
  --bg-content: #0b0f19;
  --bg-card: #141e33;
  --bg-code: #080c14;
  --bg-input: #17223b;
  --bg-hover: #1e2c4d;

  --border: #202d47;
  --border-focus: #38bdf8;

  --text-title: #f8fafc;
  --text-body: #cbd5e1;
  --text-muted: #64748b;
  --text-code: #e2e8f0;

  --accent-cyan: #38bdf8;
  --accent-cyan-hover: #0ea5e9;
  --accent-purple: #c084fc;
  --accent-green: #34d399;
  --accent-amber: #fbbf24;
  --accent-red: #f87171;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", Menlo, Monaco, Consolas, monospace;
}

[data-theme="light"] {
  --bg-page: #f8fafc;
  --bg-sidebar: #f1f5f9;
  --bg-content: #ffffff;
  --bg-card: #ffffff;
  --bg-code: #f1f5f9;
  --bg-input: #ffffff;
  --bg-hover: #e2e8f0;

  --border: #e2e8f0;
  --border-focus: #0284c7;

  --text-title: #0f172a;
  --text-body: #334155;
  --text-muted: #94a3b8;
  --text-code: #0f172a;

  --accent-cyan: #0284c7;
  --accent-cyan-hover: #0369a1;
  --accent-purple: #9333ea;
  --accent-green: #16a34a;
  --accent-amber: #d97706;
  --accent-red: #dc2626;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-page);
  color: var(--text-body);
  line-height: 1.65;
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* Header */
.learn-header {
  height: 54px;
  background-color: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  z-index: 20;
  flex-shrink: 0;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
}

.logo {
  font-size: 1.6rem;
}

.brand-name {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--accent-cyan);
}

.brand-badge {
  font-size: 0.72rem;
  background: var(--bg-card);
  color: var(--accent-purple);
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--border);
  font-weight: 600;
}

/* Search Bar */
.search-container {
  position: relative;
  width: 380px;
  max-width: 40vw;
}

.search-input {
  width: 100%;
  background-color: var(--bg-input);
  border: 1px solid var(--border);
  color: var(--text-title);
  padding: 6px 36px 6px 12px;
  border-radius: 6px;
  font-size: 0.85rem;
  outline: none;
  transition: all 0.15s;
}

.search-input:focus {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 0 2px rgba(56, 189, 248, 0.15);
}

.search-shortcut {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.7rem;
  color: var(--text-muted);
  background: var(--bg-sidebar);
  padding: 1px 5px;
  border-radius: 3px;
  border: 1px solid var(--border);
  pointer-events: none;
}

/* Nav Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.btn {
  font-family: var(--font-sans);
  font-size: 0.84rem;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-title);
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.15s;
}

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

.btn-primary {
  background: #0284c7;
  border-color: #38bdf8;
  color: #ffffff;
  font-weight: 600;
}

.btn-primary:hover {
  background: #0369a1;
}

/* Main Container */
.learn-container {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* Sidebar Navigation */
.learn-sidebar {
  width: 280px;
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 1rem 0;
  flex-shrink: 0;
  user-select: none;
}

.nav-section {
  margin-bottom: 1.25rem;
}

.nav-section-title {
  padding: 0 1.2rem;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 6px 1.2rem;
  font-size: 0.86rem;
  color: var(--text-body);
  text-decoration: none;
  cursor: pointer;
  border-left: 2px solid transparent;
  transition: all 0.15s;
}

.nav-item:hover {
  background-color: var(--bg-hover);
  color: var(--text-title);
}

.nav-item.active {
  background-color: var(--bg-card);
  color: var(--accent-cyan);
  border-left-color: var(--accent-cyan);
  font-weight: 600;
}

.nav-icon {
  font-size: 0.95rem;
  opacity: 0.85;
}

/* Main Content Area */
.learn-content {
  flex: 1;
  overflow-y: auto;
  padding: 2.5rem 3.5rem;
  background-color: var(--bg-content);
  max-width: 960px;
  margin: 0 auto;
}

.doc-chapter {
  display: none;
}

.doc-chapter.active {
  display: block;
  animation: fadeIn 0.15s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Typography */
h1 {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--text-title);
  margin-bottom: 0.6rem;
  line-height: 1.25;
}

h2 {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--text-title);
  margin-top: 2rem;
  margin-bottom: 0.8rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.3rem;
}

h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-title);
  margin-top: 1.5rem;
  margin-bottom: 0.6rem;
}

p {
  margin-bottom: 1.1rem;
  color: var(--text-body);
}

ul, ol {
  margin-bottom: 1.1rem;
  padding-left: 1.6rem;
}

li {
  margin-bottom: 0.35rem;
}

blockquote {
  border-left: 3px solid var(--accent-cyan);
  padding: 0.6rem 1rem;
  background: var(--bg-card);
  border-radius: 0 6px 6px 0;
  margin-bottom: 1.2rem;
  color: var(--text-title);
  font-style: italic;
}

/* Code Snippets & Interactive Runners */
.code-runner {
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: var(--bg-code);
  box-shadow: 0 4px 16px rgba(0,0,0,0.3);
}

.runner-header {
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
  padding: 6px 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.runner-title {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.runner-actions {
  display: flex;
  gap: 0.4rem;
}

.runner-editor {
  padding: 12px 16px;
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--text-code);
  white-space: pre;
  overflow-x: auto;
  border: none;
  outline: none;
  background: transparent;
  width: 100%;
  resize: vertical;
}

.runner-output {
  border-top: 1px solid var(--border);
  background: #050810;
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--accent-green);
  white-space: pre-wrap;
  display: none;
}

.runner-output.active {
  display: block;
}

/* "Learn the Computer" Pipeline Visualizer */
.pipeline-visualizer {
  margin: 2rem 0;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.pipeline-header {
  padding: 12px 16px;
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
}

.pipeline-steps {
  display: flex;
  overflow-x: auto;
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
}

.pipeline-step {
  padding: 8px 16px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: all 0.15s;
}

.pipeline-step:hover {
  color: var(--text-title);
}

.pipeline-step.active {
  color: var(--accent-cyan);
  border-bottom-color: var(--accent-cyan);
  background: var(--bg-card);
}

.pipeline-body {
  padding: 16px;
}

.pipeline-view {
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.55;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px;
  color: var(--text-code);
  max-height: 320px;
  overflow-y: auto;
  white-space: pre-wrap;
}

/* Standard Library Reference Table */
.stdlib-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.88rem;
}

.stdlib-table th, .stdlib-table td {
  padding: 8px 12px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.stdlib-table th {
  background: var(--bg-sidebar);
  color: var(--text-title);
  font-weight: 600;
}

.stdlib-table code {
  font-family: var(--font-mono);
  color: var(--accent-cyan);
  font-size: 0.85rem;
}

/* Search Modal */
.search-modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(2px);
  display: none;
  align-items: flex-start;
  justify-content: center;
  padding-top: 10vh;
  z-index: 50;
}

.search-modal-overlay.active {
  display: flex;
}

.search-modal-box {
  background: var(--bg-sidebar);
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 580px;
  max-width: 90vw;
  box-shadow: 0 16px 40px rgba(0,0,0,0.6);
  overflow: hidden;
}

.search-modal-input-wrap {
  padding: 12px;
  border-bottom: 1px solid var(--border);
}

.search-modal-input {
  width: 100%;
  background: var(--bg-input);
  border: 1px solid var(--border);
  color: var(--text-title);
  padding: 10px 14px;
  border-radius: 6px;
  font-size: 1rem;
  outline: none;
}

.search-results-list {
  max-height: 360px;
  overflow-y: auto;
  padding: 8px 0;
}

.search-result-item {
  padding: 8px 16px;
  display: flex;
  flex-direction: column;
  cursor: pointer;
}

.search-result-item:hover {
  background: var(--bg-hover);
}

.result-title {
  color: var(--accent-cyan);
  font-weight: 600;
  font-size: 0.9rem;
}

.result-snippet {
  color: var(--text-muted);
  font-size: 0.78rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Chapter Bottom Navigation */
.chapter-nav-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: 3.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.btn-doc-nav {
  display: inline-flex;
  flex-direction: column;
  padding: 0.85rem 1.25rem;
  border-radius: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-title);
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s;
  max-width: 48%;
}

.btn-doc-nav:hover {
  border-color: var(--accent-cyan);
  background: var(--bg-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.25);
}

.btn-doc-nav.next {
  margin-left: auto;
  text-align: right;
  align-items: flex-end;
}

.btn-doc-nav.prev {
  text-align: left;
  align-items: flex-start;
}

.nav-direction-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
  margin-bottom: 0.2rem;
}

.nav-chapter-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--accent-cyan);
}

/* Specification Tables & ISA */
.isa-table, .comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0 2rem 0;
  font-size: 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.isa-table th, .isa-table td,
.comparison-table th, .comparison-table td {
  padding: 0.65rem 0.9rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.isa-table th, .comparison-table th {
  background: var(--bg-sidebar);
  color: var(--text-title);
  font-weight: 700;
}

.isa-table tr:hover, .comparison-table tr:hover {
  background: rgba(56, 189, 248, 0.03);
}

.isa-opcode {
  font-family: var(--font-mono);
  color: var(--accent-amber);
  font-weight: 700;
}

.isa-stack {
  font-family: var(--font-mono);
  color: var(--accent-purple);
  font-size: 0.8rem;
}

.callout-box {
  background: rgba(56, 189, 248, 0.08);
  border-left: 4px solid var(--accent-cyan);
  padding: 1rem 1.25rem;
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0;
  font-size: 0.9rem;
}
.callout-box.tip {
  background: rgba(52, 211, 153, 0.08);
  border-left-color: var(--accent-green);
}
.callout-box.warn {
  background: rgba(251, 191, 36, 0.08);
  border-left-color: var(--accent-amber);
}