/* =====================================================
   NEKTUS.AI — LANDING PAGE STYLES
   ===================================================== */

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

:root {
  /* Colors */
  --bg:          #0A0B0F;
  --surface:     #111318;
  --surface-2:   #181B23;
  --border:      rgba(255, 255, 255, 0.08);
  --border-mid:  rgba(255, 255, 255, 0.14);

  --text:        #E8EAF0;
  --text-mid:    #A8ABBE;
  --text-muted:  #6A6F83;

  --accent:      #6688F8;
  --accent-dim:  rgba(102, 136, 248, 0.15);
  --accent-glow: rgba(102, 136, 248, 0.35);

  --green:       #5FDD31;
  --green-dim:   rgba(95, 221, 49, 0.15);

  --red:         #FF4E4E;
  --red-dim:     rgba(255, 78, 78, 0.15);

  --amber:       #F5A21D;
  --amber-dim:   rgba(245, 162, 29, 0.15);

  /* Typography */
  --font:        'Inter', system-ui, -apple-system, sans-serif;

  /* Spacing */
  --section-py:  96px;
  --radius:      10px;
  --radius-sm:   6px;

  /* Transitions */
  --ease:        cubic-bezier(0.4, 0, 0.2, 1);
  --dur:         220ms;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 16px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ---- Typography ---- */
h1, h2, h3 {
  line-height: 1.2;
  letter-spacing: -0.02em;
  font-weight: 700;
}

h1 { font-size: clamp(36px, 5vw, 58px); }
h2 { font-size: clamp(28px, 3.5vw, 40px); }
h3 { font-size: clamp(17px, 1.5vw, 20px); font-weight: 600; }

p { color: var(--text-mid); }

a { text-decoration: none; color: inherit; }

ul { list-style: none; }

img, svg { display: block; }

/* ---- Layout ---- */
.container {
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: var(--section-py) 0;
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-header h2 {
  margin-bottom: 12px;
}

.section-sub {
  font-size: 18px;
  color: var(--text-mid);
  max-width: 580px;
  margin: 0 auto;
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font);
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--dur) var(--ease);
  border: none;
  white-space: nowrap;
  text-decoration: none;
  padding: 10px 20px;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 0 0 0 var(--accent-glow);
}

.btn-primary:hover {
  background: #7799ff;
  box-shadow: 0 4px 24px var(--accent-glow);
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1.5px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent-dim);
  box-shadow: 0 0 16px var(--accent-glow);
}

.btn-lg {
  padding: 14px 28px;
  font-size: 16px;
}

.text-link {
  color: var(--text-mid);
  font-size: 15px;
  font-weight: 500;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.text-link:hover {
  color: var(--text);
  border-color: var(--text-mid);
}

/* ===========================================
   HEADER
   =========================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  border-bottom: 1px solid transparent;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), backdrop-filter var(--dur) var(--ease);
}

.site-header.scrolled {
  background: rgba(10, 11, 15, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-color: var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 32px;
  height: 68px;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.logo-img {
  border-radius: 8px;
}

.logo-wordmark {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text);
}

.logo-ai {
  color: var(--accent);
}

.main-nav {
  flex: 1;
}

.nav-list {
  display: flex;
  gap: 4px;
  list-style: none;
}

.nav-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-mid);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.nav-link:hover {
  color: var(--text);
  background: var(--surface-2);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-left: auto;
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: background var(--dur);
}

.hamburger:hover { background: var(--surface-2); }

.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-mid);
  border-radius: 2px;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===========================================
   HERO
   =========================================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 120px;
  padding-bottom: 80px;
  position: relative;
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.hero-eyebrow {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.hero-eyebrow::before {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

.hero-headline {
  margin-bottom: 24px;
  color: var(--text);
}

.hero-sub {
  font-size: 18px;
  line-height: 1.7;
  color: var(--text-mid);
  margin-bottom: 40px;
  max-width: 520px;
}

.hero-ctas {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

/* Hero Diagram */
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-diagram {
  display: flex;
  align-items: center;
  gap: 0;
  background: var(--surface);
  border: 1px solid var(--border-mid);
  border-radius: 16px;
  padding: 36px 28px;
  position: relative;
  box-shadow: 0 32px 80px rgba(0, 0, 0, 0.5), 0 0 0 1px var(--border);
}

.diagram-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  min-width: 80px;
}

.diagram-node span {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-mid);
  text-align: center;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.node-icon {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: var(--surface-2);
  border: 1px solid var(--border-mid);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
}

.node-icon-accent {
  background: var(--accent-dim);
  border-color: rgba(102, 136, 248, 0.3);
  color: var(--accent);
}

.node-icon-green {
  background: var(--green-dim);
  border-color: rgba(95, 221, 49, 0.3);
  color: var(--green);
}

.node-ai {
  position: relative;
}

.node-pulse {
  position: absolute;
  top: -4px;
  right: -4px;
  width: 10px;
  height: 10px;
  background: var(--green);
  border-radius: 50%;
  box-shadow: 0 0 0 0 rgba(95, 221, 49, 0.5);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 rgba(95, 221, 49, 0.5); }
  70%  { box-shadow: 0 0 0 8px rgba(95, 221, 49, 0); }
  100% { box-shadow: 0 0 0 0 rgba(95, 221, 49, 0); }
}

.diagram-arrow {
  color: var(--border-mid);
  margin: 0 -4px;
  flex-shrink: 0;
}

.diagram-badge {
  position: absolute;
  bottom: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--surface-2);
  border: 1px solid rgba(95, 221, 49, 0.3);
  border-radius: 20px;
  padding: 5px 12px;
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  font-weight: 600;
  color: var(--green);
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(0,0,0,0.4);
}

/* Hero background grid */
.hero-bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(102, 136, 248, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(102, 136, 248, 0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: -1;
}

.hero-bg-grid::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 60% 50% at 70% 50%, rgba(102, 136, 248, 0.07) 0%, transparent 70%);
}

/* ===========================================
   THE PROBLEM
   =========================================== */
.problem {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.problem-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.problem-card:hover {
  border-color: var(--border-mid);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.problem-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  border: 1px solid var(--border-mid);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  margin-bottom: 20px;
}

.problem-card h3 {
  margin-bottom: 10px;
  color: var(--text);
}

.problem-card p {
  font-size: 14px;
  line-height: 1.7;
}

/* ===========================================
   USE CASES
   =========================================== */
.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.use-case-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 32px;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
  cursor: default;
}

.use-case-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-mid);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.4);
}

.uc-emoji {
  font-size: 32px;
  margin-bottom: 16px;
  line-height: 1;
}

.use-case-card h3 {
  color: var(--text);
  margin-bottom: 4px;
}

.uc-sub {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 14px;
}

.use-case-card p {
  font-size: 14px;
  line-height: 1.7;
}

/* ===========================================
   ARCHITECTURE
   =========================================== */
.architecture {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.arch-toggle-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 40px;
}

.arch-toggle {
  display: inline-flex;
  background: var(--bg);
  border: 1px solid var(--border-mid);
  border-radius: 8px;
  padding: 4px;
  gap: 4px;
}

.arch-tab {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font);
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
  background: none;
  border: none;
  cursor: pointer;
  padding: 10px 20px;
  border-radius: 6px;
  transition: all var(--dur) var(--ease);
}

.arch-tab:hover {
  color: var(--text-mid);
  background: var(--surface-2);
}

.arch-tab.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 12px var(--accent-glow);
}

/* Panels */
.arch-panel {
  display: none;
  animation: fadeIn 300ms var(--ease);
}

.arch-panel.active {
  display: block;
}

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

.arch-panel-inner {
  background: var(--bg);
  border: 1px solid var(--border-mid);
  border-radius: var(--radius);
  padding: 40px 48px;
  max-width: 860px;
  margin: 0 auto;
}

.arch-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 16px;
}

.arch-badge-red {
  background: var(--red-dim);
  color: var(--red);
  border: 1px solid rgba(255, 78, 78, 0.25);
}

.arch-badge-blue {
  background: var(--accent-dim);
  color: var(--accent);
  border: 1px solid rgba(102, 136, 248, 0.25);
}

.arch-badge-green {
  background: var(--green-dim);
  color: var(--green);
  border: 1px solid rgba(95, 221, 49, 0.25);
}

.arch-panel-inner h3 {
  font-size: 22px;
  color: var(--text);
  margin-bottom: 28px;
}

.arch-detail {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-bottom: 36px;
}

.arch-detail-block {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
}

.arch-detail-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.arch-detail-block p {
  font-size: 14px;
  line-height: 1.7;
}

.arch-detail-block.benefit {
  border-color: var(--accent);
  border-left: 3px solid var(--accent);
}

.arch-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.arch-list li {
  font-size: 14px;
  color: var(--text-mid);
  padding-left: 18px;
  position: relative;
  line-height: 1.5;
}

.arch-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--green);
  font-weight: 700;
  font-size: 12px;
  top: 1px;
}

/* Architecture diagrams */
.arch-diagram {
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.arch-perimeter {
  border: 1.5px dashed var(--border-mid);
  border-radius: var(--radius-sm);
  padding: 16px;
  position: relative;
}

.arch-perimeter-label {
  position: absolute;
  top: -10px;
  left: 12px;
  background: var(--surface);
  padding: 0 6px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
}

.arch-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
}

.arch-flow-cloud {
  padding: 4px 0;
}

.arch-box {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-mid);
  padding: 7px 14px;
  background: var(--surface-2);
  border: 1px solid var(--border-mid);
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

.arch-box-accent {
  background: var(--accent-dim);
  border-color: rgba(102, 136, 248, 0.35);
  color: var(--accent);
}

.arch-box-amber {
  background: var(--amber-dim);
  border-color: rgba(245, 162, 29, 0.35);
  color: var(--amber);
}

.arch-flow-arrow {
  color: var(--text-muted);
  font-size: 14px;
}

.arch-box-green {
  background: var(--green-dim);
  border-color: rgba(95, 221, 49, 0.35);
  color: var(--green);
}

/* ---- Unified Architecture Layout ---- */
.arch-unified {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 0;
  align-items: stretch;
}

.arch-part {
  background: var(--bg);
  border: 1px solid var(--border-mid);
  border-radius: var(--radius);
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
}

.arch-part-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.arch-part-number {
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  background: var(--surface-2);
  border: 1px solid var(--border-mid);
  border-radius: 4px;
  padding: 3px 8px;
}

.arch-part h3 {
  font-size: 20px;
  color: var(--text);
  margin-bottom: 12px;
}

.arch-part > p {
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 20px;
}

.arch-part .arch-list {
  margin-bottom: 24px;
}

.arch-part .arch-diagram {
  margin-top: auto;
}

/* Connector between the two parts */
.arch-connector {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 0 8px;
  gap: 8px;
  align-self: stretch;
}

.arch-connector-line {
  width: 2px;
  flex: 1;
  background: linear-gradient(180deg, var(--border-mid) 0%, var(--accent) 50%, var(--border-mid) 100%);
  min-height: 40px;
  border-radius: 1px;
}

.arch-connector-badge {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  text-align: center;
  white-space: nowrap;
  background: var(--accent-dim);
  border: 1px solid rgba(102, 136, 248, 0.25);
  border-radius: 20px;
  padding: 6px 10px;
}

/* Responsive: stack on smaller screens */
@media (max-width: 900px) {
  .arch-unified {
    grid-template-columns: 1fr;
  }

  .arch-connector {
    flex-direction: row;
    min-height: auto;
    margin-top: 0;
    padding: 8px 0;
  }

  .arch-connector-line {
    width: auto;
    height: 2px;
    flex: 1;
    background: linear-gradient(90deg, var(--border-mid) 0%, var(--accent) 50%, var(--border-mid) 100%);
    min-height: auto;
    min-width: 40px;
  }
}

/* ===========================================
   PILOT PROGRAM
   =========================================== */
.timeline {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  margin-bottom: 48px;
}

.timeline-step {
  display: flex;
  flex-direction: column;
}

.timeline-step-top {
  display: flex;
  align-items: center;
  margin-bottom: 20px;
}

.step-circle {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--accent-dim);
  border: 2px solid var(--accent);
  color: var(--accent);
  font-size: 16px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.step-connector {
  flex: 1;
  height: 2px;
  background: linear-gradient(90deg, var(--accent) 0%, var(--border-mid) 100%);
  margin-left: 2px;
}

.timeline-step:last-child .step-connector {
  display: none;
}

.step-content {
  padding-right: 24px;
}

.step-content h3 {
  color: var(--text);
  margin-bottom: 8px;
  font-size: 16px;
}

.step-content p {
  font-size: 13px;
  line-height: 1.65;
}

.pilot-cta {
  text-align: center;
}

/* ===========================================
   LEAD CAPTURE FORM (CTA)
   =========================================== */
.cta-section {
  background: linear-gradient(135deg, rgba(102, 136, 248, 0.12) 0%, rgba(17, 19, 24, 0) 60%),
              var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.cta-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.cta-copy h2 {
  margin-bottom: 16px;
}

.cta-copy p {
  font-size: 17px;
  line-height: 1.7;
  margin-bottom: 32px;
}

.cta-trust-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.cta-trust-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-mid);
}

.cta-trust-list li svg {
  color: var(--green);
  flex-shrink: 0;
}

/* Form */
.cta-form {
  background: var(--bg);
  border: 1px solid var(--border-mid);
  border-radius: var(--radius);
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-row {
  display: flex;
  flex-direction: column;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-mid);
  letter-spacing: 0.01em;
}

.form-group input,
.form-group select {
  font-family: var(--font);
  font-size: 15px;
  color: var(--text);
  background: var(--surface-2);
  border: 1.5px solid var(--border-mid);
  border-radius: var(--radius-sm);
  padding: 11px 14px;
  outline: none;
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
  width: 100%;
  appearance: none;
  -webkit-appearance: none;
}

.form-group input::placeholder { color: var(--text-muted); }

.form-group input:focus,
.form-group select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.select-wrap {
  position: relative;
}

.select-wrap select {
  cursor: pointer;
  padding-right: 36px;
}

.select-icon {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

.btn-submit {
  width: 100%;
  justify-content: center;
  padding: 14px 24px;
  font-size: 16px;
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius-sm);
  border: none;
  box-shadow: 0 4px 24px var(--accent-glow);
  margin-top: 4px;
}

.btn-submit:hover {
  background: #7799ff;
  box-shadow: 0 8px 32px var(--accent-glow);
  transform: translateY(-1px);
}

.form-fine-print {
  font-size: 12px;
  color: var(--text-muted);
  text-align: center;
  line-height: 1.5;
}

.inline-link {
  color: var(--accent);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur);
}

.inline-link:hover { border-color: var(--accent); }

/* ===========================================
   FAQ
   =========================================== */
.faq-list {
  max-width: 740px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border-mid);
  border-radius: var(--radius);
  overflow: hidden;
}

.faq-item {
  border-bottom: 1px solid var(--border);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 22px 28px;
  background: var(--surface);
  border: none;
  cursor: pointer;
  font-family: var(--font);
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  text-align: left;
  transition: background var(--dur) var(--ease);
}

.faq-question:hover { background: var(--surface-2); }

.faq-icon {
  font-size: 20px;
  font-weight: 400;
  color: var(--accent);
  flex-shrink: 0;
  width: 24px;
  text-align: center;
  transition: transform var(--dur) var(--ease);
  line-height: 1;
}

.faq-question[aria-expanded="true"] .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  padding: 0 28px 24px;
  background: var(--surface);
}

.faq-answer p {
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-mid);
}

/* Animated expansion */
.faq-answer-inner {
  overflow: hidden;
}

/* ===========================================
   FOOTER
   =========================================== */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 48px 0 36px;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-tagline {
  font-size: 13px;
  color: var(--text-muted);
  margin-left: 2px;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 13px;
  color: var(--text-muted);
  transition: color var(--dur) var(--ease);
}

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

.footer-copy {
  font-size: 12px;
  color: var(--text-muted);
}

/* ===========================================
   RESPONSIVE — TABLET (≤ 1024px)
   =========================================== */
@media (max-width: 1024px) {
  :root { --section-py: 72px; }

  .hero-inner {
    gap: 48px;
  }

  .hero-diagram {
    padding: 28px 20px;
  }

  .arch-detail {
    grid-template-columns: 1fr;
    gap: 16px;
  }
}

/* ===========================================
   RESPONSIVE — MOBILE (≤ 768px)
   =========================================== */
@media (max-width: 768px) {
  :root { --section-py: 56px; }

  /* Header */
  .main-nav {
    display: none;
    position: fixed;
    top: 68px;
    left: 0;
    right: 0;
    background: rgba(10, 11, 15, 0.97);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px 24px;
  }

  .main-nav.open {
    display: block;
  }

  .nav-list {
    flex-direction: column;
    gap: 4px;
  }

  .nav-link {
    display: block;
    padding: 10px 12px;
    font-size: 16px;
  }

  .hamburger {
    display: flex;
  }

  /* Hero */
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 48px;
    text-align: center;
  }

  .hero-eyebrow {
    justify-content: center;
  }

  .hero-sub { max-width: 100%; }

  .hero-ctas {
    justify-content: center;
  }

  /* Problem */
  .problem-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  /* Use Cases */
  .use-cases-grid {
    grid-template-columns: 1fr;
  }

  /* Architecture */
  .arch-panel-inner {
    padding: 28px 24px;
  }

  .arch-tab {
    padding: 8px 14px;
    font-size: 13px;
  }

  /* Timeline */
  .timeline {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .timeline-step {
    flex-direction: row;
    gap: 20px;
    padding-bottom: 28px;
  }

  .timeline-step:last-child {
    padding-bottom: 0;
  }

  .timeline-step-top {
    flex-direction: column;
    align-items: center;
    margin-bottom: 0;
  }

  .step-connector {
    width: 2px;
    height: 100%;
    flex: 1;
    margin-left: 0;
    margin-top: 2px;
    background: linear-gradient(180deg, var(--accent) 0%, var(--border-mid) 100%);
  }

  .step-content {
    padding-right: 0;
    padding-bottom: 4px;
  }

  /* CTA form */
  .cta-inner {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  /* Footer */
  .footer-links {
    gap: 16px;
  }
}

/* ===========================================
   RESPONSIVE — SMALL (≤ 480px)
   =========================================== */
@media (max-width: 480px) {
  .hero-diagram {
    flex-direction: column;
    width: 100%;
    max-width: 260px;
  }

  .diagram-arrow {
    transform: rotate(90deg);
  }

  .diagram-badge {
    bottom: -14px;
  }

  .cta-form {
    padding: 24px 20px;
  }

  .faq-question {
    padding: 18px 20px;
    font-size: 14px;
  }

  .faq-answer {
    padding: 0 20px 20px;
  }
}