/* ==========================================================================
   Harness Kit — Central Unified Stylesheet (css/style.css)
   ========================================================================== */

/* --------------------------------------------------------------------------
   Design Tokens
   -------------------------------------------------------------------------- */
:root {
  --bg:            #080c18;
  --bg-raised:     #0d1220;
  --bg-card:       #0f1320;
  --bg-code:       #060a12;
  --border:        rgba(255, 255, 255, 0.07);
  --border-hover:  rgba(99, 102, 241, 0.35);

  --primary:       #6366f1;
  --primary-dim:   rgba(99, 102, 241, 0.12);
  --amber:         #f59e0b;
  --amber-dim:     rgba(245, 158, 11, 0.12);
  --success:       #10b981;
  --success-dim:   rgba(16, 185, 129, 0.12);
  --danger:        #f43f5e;
  --danger-dim:    rgba(244, 63, 94, 0.10);

  --text:          #f1f5f9;
  --text-muted:    #94a3b8;
  --text-faint:    #4b5563;

  --font-sans:     'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono:     'Fira Code', monospace;
  --radius:        10px;
  --radius-lg:     14px;
  --transition:    0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --------------------------------------------------------------------------
   Base Reset & Globals
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.65;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Multilingual visibility toggles */
body.lang-vi [lang="en"] { display: none !important; }
body.lang-en [lang="vi"] { display: none !important; }

/* Custom Scrollbar */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: rgba(99, 102, 241, 0.25); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: rgba(99, 102, 241, 0.45); }

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

a:hover {
  color: var(--amber);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* Layout Containers */
.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
.container-narrow { max-width: 860px; margin: 0 auto; padding: 0 24px; }
.container-medium { max-width: 1000px; margin: 0 auto; padding: 0 24px; }

/* --------------------------------------------------------------------------
   Header Navigation (Unified across all pages)
   -------------------------------------------------------------------------- */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(8, 12, 24, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.header-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 15px;
  color: var(--text);
  letter-spacing: -0.01em;
}

.brand svg { width: 22px; height: 22px; }
.brand .dot { color: var(--primary); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-links a:not(.btn-github) {
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition), background var(--transition);
}

.nav-links a:not(.btn-github):hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.05);
}

.nav-links a.active-page {
  color: var(--primary);
  font-weight: 600;
  background: var(--primary-dim);
}

.btn-github {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border-radius: 7px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  border: 1px solid var(--border);
  transition: all var(--transition);
  margin-left: 4px;
}

.btn-github:hover {
  color: var(--text);
  border-color: var(--border-hover);
  background: var(--primary-dim);
  transform: translateY(-1px);
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 7px;
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 11.5px;
  margin-left: 8px;
}

.lang-btn {
  padding: 6px 11px;
  color: var(--text-muted);
  transition: all var(--transition);
  font-family: inherit;
  font-size: inherit;
  font-weight: 600;
}

.lang-btn.active {
  background: var(--primary);
  color: #fff;
}

.lang-btn:hover:not(.active) {
  color: var(--text);
  background: rgba(255, 255, 255, 0.05);
}

/* --------------------------------------------------------------------------
   Footer Navigation (Unified across all pages)
   -------------------------------------------------------------------------- */
footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  font-size: 13px;
  color: var(--text-faint);
  margin-top: 80px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13.5px;
  color: var(--text);
  font-weight: 600;
}

.footer-links {
  display: flex;
  gap: 16px;
  align-items: center;
}

.footer-links a {
  color: var(--text-muted);
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--text);
}

/* --------------------------------------------------------------------------
   Section Layouts & Headers
   -------------------------------------------------------------------------- */
.section {
  padding: 80px 0;
  border-bottom: 1px solid var(--border);
}

.section-head {
  text-align: center;
  margin-bottom: 48px;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(24px, 4vw, 36px);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.2;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 15px;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto;
  line-height: 1.65;
}

/* --------------------------------------------------------------------------
   Hero Section & Terminal Demo Widget
   -------------------------------------------------------------------------- */
.hero {
  padding: 72px 0 64px;
  text-align: center;
  position: relative;
  border-bottom: 1px solid var(--border);
}

.hero .badge-top {
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(2.2rem, 5.5vw, 3.8rem);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.035em;
  margin-bottom: 20px;
}

.grad {
  background: linear-gradient(135deg, #ffffff 0%, var(--primary) 60%, #a5b4fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: clamp(15px, 2vw, 17.5px);
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 32px;
  line-height: 1.65;
}

.hero-desc strong {
  color: var(--text);
}

.hero-actions {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 14px;
  margin-bottom: 56px;
  flex-wrap: wrap;
}

/* Terminal Widget */
.terminal-container {
  max-width: 760px;
  margin: 0 auto;
  background: #060a12;
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.6), 0 0 30px rgba(99, 102, 241, 0.1);
  text-align: left;
}

.terminal-header {
  background: #0c101d;
  padding: 10px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
}

.terminal-dots {
  display: flex;
  gap: 6px;
}

.terminal-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}

.d-red { background: #ff5f56; }
.d-yellow { background: #ffbd2e; }
.d-green { background: #27c93f; }

.terminal-title {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--text-faint);
  font-weight: 500;
}

.terminal-body {
  padding: 20px 22px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
}

.terminal-line {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  word-break: break-all;
}

.t-prompt {
  color: var(--primary);
  font-weight: 700;
  user-select: none;
}

.t-cmd {
  color: #cbd5e1;
  font-weight: 600;
}

.t-out {
  color: var(--text-muted);
  font-size: 12.5px;
  padding-left: 36px;
  margin: 4px 0 8px;
  white-space: pre-wrap;
}

.t-ok {
  color: var(--success);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   Subsystems Grid
   -------------------------------------------------------------------------- */
.grid-subsystems {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
}

.card-icon {
  width: 38px;
  height: 38px;
  border-radius: 8px;
  background: var(--primary-dim);
  border: 1px solid rgba(99, 102, 241, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.card-icon svg {
  stroke: var(--primary);
}

.card-title {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}

.card-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 16px;
}

.card-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--primary);
  background: var(--primary-dim);
  padding: 3px 8px;
  border-radius: 4px;
  display: inline-block;
}

/* --------------------------------------------------------------------------
   Interactive CLI Builder Widget
   -------------------------------------------------------------------------- */
.builder-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px;
}

.builder-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 36px;
  align-items: start;
}

.builder-form-title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 8px;
}

.builder-form-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  margin-bottom: 24px;
  line-height: 1.6;
}

.form-group label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--text-faint);
  text-transform: uppercase;
  margin-bottom: 8px;
}

.generated-code-wrap {
  position: relative;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 16px;
}

.builder-info-box {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid rgba(99, 102, 241, 0.2);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 13px;
  color: var(--text-muted);
}

.builder-info-box svg {
  width: 16px;
  height: 16px;
  stroke: var(--primary);
  flex-shrink: 0;
  margin-top: 2px;
}

/* --------------------------------------------------------------------------
   Architecture Flow Visualizer
   -------------------------------------------------------------------------- */
.flow-container {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px;
}

.flow-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 40px;
  align-items: center;
}

.flow-visual {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.flow-node {
  width: 100%;
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.flow-node-title {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--text);
}

.flow-node-badge {
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--primary);
  background: var(--primary-dim);
  padding: 2px 7px;
  border-radius: 4px;
}

.flow-arrow {
  color: var(--primary);
  display: flex;
  justify-content: center;
}

.flow-content h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 12px;
}

.flow-content p {
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 20px;
  line-height: 1.65;
}

.flow-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.flow-list li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.6;
}

.flow-list li svg {
  width: 16px;
  height: 16px;
  stroke: var(--success);
  flex-shrink: 0;
  margin-top: 3px;
}

.flow-list li strong {
  color: var(--text);
}

/* --------------------------------------------------------------------------
   Installation Section & Table
   -------------------------------------------------------------------------- */
.install-quick-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 24px;
}

.install-mode-label {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
}

.install-os-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--text-faint);
  text-transform: uppercase;
  margin-bottom: 6px;
}

.install-req {
  font-size: 12.5px;
  color: var(--text-muted);
  font-family: var(--font-mono);
  margin-top: 16px;
}

.install-files-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
  font-size: 13.5px;
}

.install-files-table th {
  text-align: left;
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--text-faint);
  text-transform: uppercase;
  border-bottom: 1px solid var(--border);
}

.install-files-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}

.install-files-table td:first-child {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--primary);
  font-weight: 600;
}

.install-files-table tr:last-child td {
  border-bottom: none;
}

/* --------------------------------------------------------------------------
   IDE Setup Section
   -------------------------------------------------------------------------- */
.setup-tab-navs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.setup-tab-pill {
  padding: 9px 20px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-muted);
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}

.setup-tab-pill:hover {
  color: var(--text);
  border-color: var(--border-hover);
}

.setup-tab-pill.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.25);
}

.setup-content-box {
  display: none;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px;
}

.setup-content-box.active {
  display: block;
  animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

.prereq-note {
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.25);
  border-radius: var(--radius);
  padding: 14px 18px;
  font-size: 13.5px;
  color: var(--text-muted);
  margin-bottom: 32px;
}

.prereq-note strong {
  color: var(--amber);
}

.setup-step {
  padding: 24px 0;
  border-bottom: 1px solid var(--border);
}

.setup-step:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.setup-step-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--primary);
  background: var(--primary-dim);
  border: 1px solid rgba(99, 102, 241, 0.25);
  padding: 3px 9px;
  border-radius: 999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 10px;
}

.setup-step-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
  line-height: 1.3;
}

.setup-step-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 16px;
}

/* --------------------------------------------------------------------------
   Buttons & Interactive Elements
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 14.5px;
  transition: all var(--transition);
  cursor: pointer;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.25);
}

.btn-primary:hover {
  background: #5254e0;
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.35);
}

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

.btn-secondary:hover {
  color: var(--text);
  border-color: var(--border-hover);
  background: var(--primary-dim);
  transform: translateY(-1px);
}

/* --------------------------------------------------------------------------
   Badges, Labels & Indicators
   -------------------------------------------------------------------------- */
.badge-top, .page-label, .gs-label, .hero .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 14px;
  font-size: 11.5px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-family: var(--font-mono);
  margin-bottom: 24px;
}

.badge-dot, .page-label .dot, .gs-label span:first-child {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--success);
  display: inline-block;
  flex-shrink: 0;
  animation: pulse 2.4s infinite;
}

.page-label .dot.amber { background: var(--amber); }

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.time-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--success-dim);
  border: 1px solid rgba(16, 185, 129, 0.25);
  border-radius: 8px;
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--success);
  font-family: var(--font-mono);
}

.mode-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 4px;
  letter-spacing: 0.06em;
  vertical-align: middle;
}

.mode-gov {
  background: rgba(16, 185, 129, 0.1);
  color: var(--success);
  border: 1px solid rgba(16, 185, 129, 0.25);
}

.mode-full {
  background: rgba(245, 158, 11, 0.1);
  color: var(--amber);
  border: 1px solid rgba(245, 158, 11, 0.25);
}

.file-badge {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-family: var(--font-mono);
  padding: 3px 8px;
  border-radius: 5px;
  background: var(--primary-dim);
  color: var(--primary);
  border: 1px solid rgba(99, 102, 241, 0.2);
}

.file-badge.amber {
  background: var(--amber-dim);
  color: var(--amber);
  border-color: rgba(245, 158, 11, 0.2);
}

/* --------------------------------------------------------------------------
   Code Blocks & Syntax Highlighting
   -------------------------------------------------------------------------- */
code {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--primary);
  background: var(--primary-dim);
  border-radius: 4px;
  padding: 2px 6px;
}

code.inline {
  background: rgba(99, 102, 241, 0.1);
  color: var(--text-muted);
}

.code-wrap, .code-block-wrap {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  position: relative;
  margin-bottom: 16px;
}

.code-file-bar {
  background: #0b1022;
  border: 1px solid var(--border);
  border-bottom: none;
  border-radius: 7px 7px 0 0;
  padding: 8px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.code-file-name {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--text-faint);
}

.code-lang-tag {
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--primary);
  background: var(--primary-dim);
  padding: 2px 7px;
  border-radius: 3px;
}

pre.code, pre.code-block, .code-wrap pre, .code-block-wrap pre {
  background: var(--bg-code);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.65;
  color: #cbd5e1;
  padding: 16px 18px;
  overflow-x: auto;
  white-space: pre;
}

pre.code.has-bar {
  border-radius: 0 0 7px 7px;
  margin-top: 0;
}

.code-os, .code-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-family: var(--font-mono);
  color: var(--text-faint);
  padding: 10px 16px 0;
  display: block;
}

/* Syntax tokens */
pre.code .c, .t-comment { color: var(--text-faint); font-style: italic; }
pre.code .k { color: #93b4d8; }
pre.code .s { color: var(--amber); }
pre.code .n { color: #60a5fa; }
pre.code .v { color: #7dd3fc; }

.btn-copy, .btn-copy-inline {
  position: absolute;
  top: 10px;
  right: 10px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border);
  padding: 5px 11px;
  border-radius: 6px;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  display: flex;
  align-items: center;
  gap: 5px;
}

.btn-copy:hover, .btn-copy-inline:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--border-hover);
}

.btn-copy.copied, .btn-copy-inline.copied {
  color: var(--success);
  border-color: rgba(16, 185, 129, 0.3);
  background: var(--success-dim);
}

.concept-grid, .modes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 16px;
  margin-top: 32px;
  text-align: left;
}

.next-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
}

.card, .mode-card, .concept-card, .next-card, .case {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
  position: relative;
}

.card:hover, .mode-card:hover, .concept-card:hover, .next-card:hover {
  border-color: var(--border-hover);
}

.concept-card.highlighted {
  border-color: rgba(99, 102, 241, 0.3);
  background: rgba(99, 102, 241, 0.06);
}

.callout {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  border: 1px solid rgba(99, 102, 241, 0.25);
  background: rgba(99, 102, 241, 0.06);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 13.5px;
  color: var(--text-muted);
  margin-top: 16px;
}

.callout svg { width: 16px; height: 16px; stroke: var(--primary); flex-shrink: 0; margin-top: 2px; }
.callout.success { border-color: rgba(16, 185, 129, 0.25); background: rgba(16, 185, 129, 0.06); }
.callout.success svg { stroke: var(--success); }

.pain {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 14px 18px;
  margin: 0 0 28px;
  background: rgba(244, 63, 94, 0.05);
  border-left: 3px solid var(--danger);
  border-radius: 4px;
}

.pain .label {
  flex: 0 0 56px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  color: var(--danger);
  letter-spacing: 0.1em;
  padding-top: 2px;
  text-transform: uppercase;
}

.pain .text { color: var(--text); font-size: 14.5px; line-height: 1.6; }

.result {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 14px 18px;
  margin-top: 12px;
  background: rgba(16, 185, 129, 0.05);
  border-left: 3px solid var(--success);
  border-radius: 4px;
}

.result .label {
  flex: 0 0 56px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  color: var(--success);
  letter-spacing: 0.1em;
  padding-top: 2px;
  text-transform: uppercase;
}

.result .text { color: var(--text); font-size: 14px; line-height: 1.6; }

/* --------------------------------------------------------------------------
   Toggles, Tabs & Controls
   -------------------------------------------------------------------------- */
.os-toggle, .os-pill-group {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
}

.os-btn, .os-pill {
  padding: 7px 16px;
  color: var(--text-muted);
  font-weight: 600;
  transition: all var(--transition);
  font-family: inherit;
  font-size: inherit;
  border: none;
  background: none;
  cursor: pointer;
}

.os-btn.active, .os-pill.active {
  background: var(--primary);
  color: #fff;
}

.os-btn:hover:not(.active), .os-pill:hover:not(.active) {
  color: var(--text);
  background: rgba(255, 255, 255, 0.05);
}

.tabs-header {
  display: flex;
  border-bottom: 1px solid var(--border);
  margin-bottom: 20px;
  gap: 0;
  overflow-x: auto;
}

.tab-btn {
  background: transparent;
  color: var(--text-muted);
  padding: 9px 16px;
  font-family: var(--font-sans);
  font-size: 13.5px;
  font-weight: 600;
  border: none;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
  white-space: nowrap;
  cursor: pointer;
}

.tab-btn:hover { color: var(--text); }
.tab-btn.active { color: var(--primary); border-color: var(--primary); }

/* --------------------------------------------------------------------------
   Lists, Workflows & Hero Styles
   -------------------------------------------------------------------------- */
.file-list { display: flex; flex-direction: column; gap: 10px; }

.file-row {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  transition: border-color var(--transition);
}

.file-row:hover { border-color: var(--border-hover); }

.file-icon {
  width: 32px; height: 32px; border-radius: 7px;
  background: var(--primary-dim); border: 1px solid rgba(99, 102, 241, 0.2);
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}

.file-icon svg { width: 15px; height: 15px; stroke: var(--primary); }

.file-name {
  font-family: var(--font-mono); font-size: 13px; font-weight: 600;
  color: var(--text); margin-bottom: 2px;
}

.file-desc { font-size: 13px; color: var(--text-muted); }

/* Step Workflow */
.gs-step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 0 24px;
  padding: 40px 0;
  border-bottom: 1px solid var(--border);
}

.gs-step:last-child { border-bottom: none; }

.step-num-col {
  display: flex; flex-direction: column; align-items: center;
  padding-top: 4px;
}

.step-num {
  width: 36px; height: 36px; border-radius: 50%; flex-shrink: 0;
  background: var(--primary-dim); border: 1.5px solid var(--primary);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-weight: 800; color: var(--primary);
  font-family: var(--font-mono);
}

.step-line {
  flex: 1; width: 1px; background: var(--border);
  margin-top: 8px; min-height: 20px;
}

.step-content { min-width: 0; }

.step-tag {
  font-size: 11px; font-weight: 700; letter-spacing: 0.1em;
  text-transform: uppercase; font-family: var(--font-mono);
  color: var(--primary); margin-bottom: 6px;
}

.step-title {
  font-size: 22px; font-weight: 700; letter-spacing: -0.02em;
  margin-bottom: 10px; line-height: 1.25;
}

.step-desc {
  font-size: 14px; color: var(--text-muted); margin-bottom: 20px;
  max-width: 600px;
}

.step-list { list-style: none; counter-reset: step; padding-left: 0; }

.step-list > li {
  counter-increment: step;
  position: relative;
  padding: 0 0 28px 48px;
  border-left: 1px solid var(--border);
  margin-left: 15px;
}

.step-list > li:last-child { border-left-color: transparent; padding-bottom: 0; }

.step-list > li::before {
  content: counter(step);
  position: absolute; left: -15px; top: 0;
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--bg-raised);
  border: 1px solid var(--primary);
  color: var(--primary); font-family: var(--font-mono);
  font-size: 11px; font-weight: 600;
  display: flex; align-items: center; justify-content: center;
}

.step-list > li > h3 {
  font-size: 15px; font-weight: 600; margin-bottom: 8px;
  color: var(--text); padding-top: 2px;
}

.step-list > li > p {
  color: var(--text-muted); font-size: 13.5px; margin-bottom: 12px;
  line-height: 1.65;
}

/* --------------------------------------------------------------------------
   Responsive Layout & Breakpoints
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .builder-grid { grid-template-columns: 1fr; }
  .flow-grid { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 720px) {
  .nav-links a:not(.btn-github):not(.active-page) { display: none; }
  .gs-step { grid-template-columns: 40px 1fr; gap: 0 16px; }
  .step-num { width: 30px; height: 30px; font-size: 12px; }
  .footer-inner { flex-direction: column; align-items: flex-start; gap: 12px; }
}

@media (max-width: 600px) {
  .modes-grid, .concept-grid { grid-template-columns: 1fr; }
  .hero-title, .gs-hero h1 { font-size: 1.85rem; }
  .container { padding: 0 16px; }
}