/* ==========================================================================
   Research Methodology for AI Systems - Course Website Styles
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Custom Properties (Design Tokens)
   -------------------------------------------------------------------------- */
:root {
  /* Colors */
  --color-primary: #1e3a5f;
  --color-primary-light: #2d5a8a;
  --color-primary-dark: #0f2744;
  --color-accent: #c9553d;
  --color-accent-light: #e07860;
  --color-accent-dark: #a13d28;

  --color-text: #2c3e50;
  --color-text-light: #5a6c7d;
  --color-text-muted: #8899a6;

  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fb;
  --color-bg-dark: #1e3a5f;

  --color-border: #e1e5eb;
  --color-border-light: #f0f2f5;

  --color-success: #27ae60;
  --color-warning: #f39c12;
  --color-error: #e74c3c;

  /* Typography */
  --font-serif: 'Source Serif 4', Georgia, serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Layout */
  --container-max: 1200px;
  --container-narrow: 800px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.15);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
}

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

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

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.3;
  margin: 0 0 var(--space-md) 0;
  color: var(--color-primary-dark);
}

h1 { font-size: 3rem; font-weight: 700; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
  margin: 0 0 var(--space-md) 0;
}

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

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

ul, ol {
  margin: 0 0 var(--space-md) 0;
  padding-left: var(--space-xl);
}

li {
  margin-bottom: var(--space-sm);
}

blockquote {
  margin: var(--space-lg) 0;
  padding: var(--space-md) var(--space-lg);
  border-left: 4px solid var(--color-accent);
  background: var(--color-bg-alt);
  font-style: italic;
  color: var(--color-text-light);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-bg-alt);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
}

img {
  max-width: 100%;
  height: auto;
}

/* --------------------------------------------------------------------------
   Layout Components
   -------------------------------------------------------------------------- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section {
  padding: var(--space-4xl) 0;
}

.section-alt {
  background-color: var(--color-bg-alt);
}

.section-title {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: var(--space-lg);
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: var(--color-accent);
  margin: var(--space-md) auto 0;
  border-radius: 2px;
}

.section-intro {
  text-align: center;
  font-size: 1.125rem;
  color: var(--color-text-light);
  max-width: 700px;
  margin: 0 auto var(--space-2xl);
  line-height: 1.7;
}

/* --------------------------------------------------------------------------
   Navigation
   -------------------------------------------------------------------------- */
.main-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition-base);
}

.main-nav.scrolled {
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-primary-dark);
}

.nav-logo:hover {
  color: var(--color-primary);
}

.nav-links {
  display: flex;
  gap: var(--space-xl);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-light);
  padding: var(--space-sm) 0;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

.nav-links a:hover {
  color: var(--color-primary-dark);
}

.nav-links a:hover::after {
  width: 100%;
}

/* Nav dropdowns */
.nav-dropdown {
  position: relative;
}

.nav-dropdown > a {
  cursor: pointer;
}

.nav-dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: var(--space-sm) 0;
  min-width: 200px;
  z-index: 1000;
  list-style: none;
  margin-top: var(--space-xs);
}

.nav-dropdown:hover .nav-dropdown-menu {
  display: block;
}

.nav-dropdown-menu li {
  padding: 0;
}

.nav-dropdown-menu a {
  display: block;
  padding: var(--space-sm) var(--space-lg);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-light);
  text-decoration: none;
  white-space: nowrap;
}

.nav-dropdown-menu a:hover {
  background: var(--color-bg-alt);
  color: var(--color-primary-dark);
}

.nav-dropdown-menu a::after {
  display: none;
}

/* --------------------------------------------------------------------------
   Hero Section
   -------------------------------------------------------------------------- */
.hero {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 50%, var(--color-primary-light) 100%);
  color: white;
  padding: calc(var(--space-4xl) + 70px) 0 var(--space-4xl);
  min-height: 85vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(circle at 20% 80%, rgba(201, 85, 61, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(255, 255, 255, 0.08) 0%, transparent 40%);
  pointer-events: none;
}

.hero-content {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-xl);
  position: relative;
  z-index: 1;
}

.hero-label {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--color-accent-light);
  margin-bottom: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 700;
  color: white;
  margin-bottom: var(--space-md);
  line-height: 1.15;
  max-width: 700px;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: rgba(255, 255, 255, 0.75);
  margin-bottom: var(--space-lg);
  font-weight: 500;
}

.hero-description {
  font-size: 1.25rem;
  color: rgba(255, 255, 255, 0.9);
  max-width: 550px;
  line-height: 1.7;
  margin-bottom: var(--space-2xl);
}

.hero-cta {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-md) var(--space-xl);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
}

.btn-primary {
  background: var(--color-accent);
  color: white;
  border-color: var(--color-accent);
}

.btn-primary:hover {
  background: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  color: white;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: transparent;
  color: white;
  border-color: rgba(255, 255, 255, 0.4);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: white;
  color: white;
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: white;
}

/* --------------------------------------------------------------------------
   Focus Cards (Course Overview)
   -------------------------------------------------------------------------- */
.focus-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-xl);
  margin-bottom: var(--space-3xl);
}

.focus-card {
  background: white;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
}

.focus-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-accent);
}

.focus-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: white;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-md);
}

.focus-card h3 {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
}

.focus-card p {
  color: var(--color-text-light);
  font-size: 0.95rem;
  margin: 0;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   Running Example & Pedagogy
   -------------------------------------------------------------------------- */
.running-example {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: white;
  padding: var(--space-2xl);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-2xl);
}

.running-example h3 {
  color: white;
  margin-bottom: var(--space-md);
}

.running-example p {
  margin: 0;
  line-height: 1.7;
  opacity: 0.95;
}

.running-example strong {
  color: var(--color-accent-light);
}

.running-example em {
  color: rgba(255, 255, 255, 0.85);
}

.pedagogy {
  background: var(--color-bg-alt);
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
}

.pedagogy h3 {
  text-align: center;
  margin-bottom: var(--space-lg);
}

.pedagogy-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.pedagogy-step {
  background: white;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-weight: 500;
  color: var(--color-primary-dark);
  border: 1px solid var(--color-border);
  font-size: 0.9rem;
}

.pedagogy-arrow {
  color: var(--color-accent);
  font-size: 1.25rem;
  font-weight: bold;
}

/* --------------------------------------------------------------------------
   Session Cards
   -------------------------------------------------------------------------- */
.session-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: var(--space-xl);
}

.session-card {
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
}

.session-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.session-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-md);
}

.session-number {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  background: rgba(201, 85, 61, 0.1);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
}

.session-duration {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.session-date {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
  font-family: var(--font-sans);
}

.session-card h3 {
  font-size: 1.5rem;
  margin-bottom: var(--space-sm);
  color: var(--color-primary-dark);
}

.session-question {
  font-size: 1.1rem;
  color: var(--color-text-light);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border-light);
}

.session-content {
  flex: 1;
}

.session-content h4 {
  font-size: 0.9rem;
  font-family: var(--font-sans);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  margin: var(--space-lg) 0 var(--space-sm);
}

.session-content h4:first-child {
  margin-top: 0;
}

.session-content ul {
  list-style: none;
  padding: 0;
  margin: 0 0 var(--space-md) 0;
}

.session-content li {
  position: relative;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-sm);
  font-size: 0.95rem;
  color: var(--color-text-light);
}

.session-content li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  background: var(--color-accent);
  border-radius: 50%;
}

.session-artifacts {
  background: var(--color-bg-alt);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  margin: var(--space-lg) 0;
}

.session-artifacts h4 {
  font-size: 0.85rem;
  font-family: var(--font-sans);
  font-weight: 600;
  color: var(--color-primary-dark);
  margin: 0 0 var(--space-sm) 0;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.session-artifacts ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.session-artifacts li {
  font-size: 0.9rem;
  color: var(--color-text-light);
  padding: var(--space-xs) 0;
}

.session-artifacts li::before {
  content: '\2713';
  color: var(--color-success);
  margin-right: var(--space-sm);
  font-weight: bold;
}

.session-card .btn-outline {
  margin-top: auto;
  text-align: center;
}

/* --------------------------------------------------------------------------
   Concepts Grid
   -------------------------------------------------------------------------- */
.concepts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--space-lg);
}

.concept {
  background: white;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--color-accent);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.concept:hover {
  box-shadow: var(--shadow-md);
  transform: translateX(4px);
}

.concept h4 {
  color: var(--color-primary-dark);
  margin-bottom: var(--space-sm);
  font-size: 1.1rem;
}

.concept p {
  margin: 0;
  color: var(--color-text-light);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   Materials Grid
   -------------------------------------------------------------------------- */
.materials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.material-card {
  background: white;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
}

.material-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-light);
}

.material-card h4 {
  color: var(--color-primary-dark);
  margin-bottom: var(--space-sm);
}

.material-card p {
  color: var(--color-text-light);
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.material-link {
  font-weight: 600;
  font-size: 0.95rem;
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
}

.material-link:hover {
  gap: var(--space-sm);
}

/* --------------------------------------------------------------------------
   Anti-Patterns Gallery
   -------------------------------------------------------------------------- */
.antipattern-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: var(--space-lg);
}

.antipattern-card {
  background: white;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  position: relative;
  overflow: hidden;
}

.antipattern-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-error), var(--color-warning));
}

.antipattern-session {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.antipattern-card h4 {
  color: var(--color-primary-dark);
  margin-bottom: var(--space-md);
}

.antipattern-card blockquote {
  background: var(--color-bg-alt);
  border-left-color: var(--color-warning);
  margin: 0 0 var(--space-md) 0;
  font-size: 0.9rem;
}

.antipattern-problem {
  color: var(--color-error);
  font-size: 0.9rem;
  font-weight: 500;
  margin: 0;
  padding: var(--space-sm);
  background: rgba(231, 76, 60, 0.08);
  border-radius: var(--radius-sm);
}

/* --------------------------------------------------------------------------
   Outcomes Section
   -------------------------------------------------------------------------- */
.outcomes-list {
  max-width: 700px;
  margin: 0 auto var(--space-2xl);
  list-style: none;
  padding: 0;
}

.outcomes-list li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border-light);
  font-size: 1.05rem;
}

.outcomes-list li::before {
  content: '\2713';
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  background: var(--color-success);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  font-weight: bold;
}

.meta-skill {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: white;
  padding: var(--space-2xl);
  border-radius: var(--radius-lg);
  text-align: center;
  max-width: 700px;
  margin: 0 auto;
}

.meta-skill h3 {
  color: white;
  margin-bottom: var(--space-md);
}

.meta-skill-quote {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-style: italic;
  margin-bottom: var(--space-md);
  color: var(--color-accent-light);
}

.meta-skill p:last-child {
  margin: 0;
  opacity: 0.9;
  font-size: 1.05rem;
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.footer {
  background: var(--color-primary-dark);
  color: white;
  padding: var(--space-2xl) 0;
  text-align: center;
}

.footer p {
  margin: 0;
  font-size: 1rem;
}

.footer-sub {
  margin-top: var(--space-sm) !important;
  opacity: 0.7;
  font-size: 0.9rem !important;
}

/* --------------------------------------------------------------------------
   Responsive Design
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .hero h1 {
    font-size: 2.5rem;
  }

  .section-title {
    font-size: 2rem;
  }

  .session-cards {
    grid-template-columns: 1fr;
  }

  .nav-links {
    display: none;
  }

  .pedagogy-flow {
    flex-direction: column;
  }

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

@media (max-width: 600px) {
  :root {
    font-size: 15px;
  }

  .hero {
    min-height: auto;
    padding: calc(var(--space-3xl) + 70px) 0 var(--space-3xl);
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-description {
    font-size: 1.1rem;
  }

  .hero-cta {
    flex-direction: column;
  }

  .hero-cta .btn {
    width: 100%;
  }

  .section {
    padding: var(--space-2xl) 0;
  }

  .container {
    padding: 0 var(--space-md);
  }

  .focus-grid,
  .concepts-grid,
  .materials-grid,
  .antipattern-grid {
    grid-template-columns: 1fr;
  }

  .meta-skill-quote {
    font-size: 1.4rem;
  }
}

/* --------------------------------------------------------------------------
   Utility Classes
   -------------------------------------------------------------------------- */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: var(--space-md); }
.mt-2 { margin-top: var(--space-xl); }
.mt-3 { margin-top: var(--space-2xl); }

.mb-1 { margin-bottom: var(--space-md); }
.mb-2 { margin-bottom: var(--space-xl); }
.mb-3 { margin-bottom: var(--space-2xl); }

/* --------------------------------------------------------------------------
   Animations
   -------------------------------------------------------------------------- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.6s ease forwards;
}

/* Staggered animation delays for grid items */
.focus-card:nth-child(1) { animation-delay: 0.1s; }
.focus-card:nth-child(2) { animation-delay: 0.2s; }
.focus-card:nth-child(3) { animation-delay: 0.3s; }
.focus-card:nth-child(4) { animation-delay: 0.4s; }

.session-card:nth-child(1) { animation-delay: 0.1s; }
.session-card:nth-child(2) { animation-delay: 0.2s; }
.session-card:nth-child(3) { animation-delay: 0.3s; }
.session-card:nth-child(4) { animation-delay: 0.4s; }