/* ==========================================================================
   VITALDRIVE RESEARCH INSTITUTE - STYLESHEET
   Namespace: vd- | Architectural Profile: Athletic Biomechanics & Kinematics
   ========================================================================== */

:root {
  --vd-primary: #0284c7;
  --vd-primary-dark: #0369a1;
  --vd-primary-light: #e0f2fe;
  --vd-teal: #0f766e;
  --vd-teal-light: #ccfbf1;
  --vd-accent: #d97706;
  --vd-dark: #0f172a;
  --vd-dark-alt: #1e293b;
  --vd-slate: #334155;
  --vd-muted: #64748b;
  --vd-light: #f8fafc;
  --vd-white: #ffffff;
  --vd-border: #e2e8f0;
  --vd-border-dark: #cbd5e1;
  --vd-radius-sm: 6px;
  --vd-radius-md: 10px;
  --vd-radius-lg: 16px;
  --vd-shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
  --vd-shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --vd-shadow-lg: 0 10px 25px -5px rgba(15, 23, 42, 0.12);
  --vd-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --vd-font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

html {
  font-family: var(--vd-font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--vd-slate);
  background-color: var(--vd-light);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Scroll progress */
.vd-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--vd-primary), var(--vd-teal), var(--vd-accent));
  width: 0%;
  z-index: 1000;
  transition: width 0.1s ease;
}

/* Container */
.vd-container {
  width: 100%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.vd-container-narrow {
  max-width: 860px;
}

/* Top bar */
.vd-topbar {
  background-color: var(--vd-dark);
  color: #94a3b8;
  font-size: 0.8125rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid #1e293b;
}

.vd-topbar-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.vd-topbar-info span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-right: 1.25rem;
}

.vd-topbar-entity {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: #cbd5e1;
}

/* Header */
.vd-header {
  background-color: var(--vd-white);
  border-bottom: 1px solid var(--vd-border);
  position: sticky;
  top: 0;
  z-index: 900;
  box-shadow: var(--vd-shadow-sm);
}

.vd-nav-wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 72px;
}

.vd-brand {
  display: flex;
  align-items: center;
  text-decoration: none;
  gap: 0.75rem;
}

.vd-brand img {
  height: 42px;
  width: auto;
  display: block;
}

.vd-nav-menu {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.vd-nav-link {
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--vd-dark-alt);
  text-decoration: none;
  padding: 0.5rem 0.25rem;
  position: relative;
  transition: color 0.2s ease;
}

.vd-nav-link:hover,
.vd-nav-link.active {
  color: var(--vd-primary);
}

.vd-nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--vd-primary);
  border-radius: 2px;
}

.vd-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.9375rem;
  padding: 0.65rem 1.35rem;
  border-radius: var(--vd-radius-md);
  text-decoration: none;
  transition: all 0.2s ease;
  cursor: pointer;
  border: 1px solid transparent;
}

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

.vd-btn-primary:hover {
  background-color: var(--vd-primary-dark);
  box-shadow: var(--vd-shadow-sm);
}

.vd-btn-secondary {
  background-color: var(--vd-teal);
  color: var(--vd-white);
}

.vd-btn-secondary:hover {
  background-color: #115e59;
}

.vd-btn-outline {
  background-color: transparent;
  border-color: var(--vd-border-dark);
  color: var(--vd-dark-alt);
}

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

.vd-btn-white {
  background-color: var(--vd-white);
  color: var(--vd-primary-dark);
}

.vd-btn-white:hover {
  background-color: var(--vd-light);
}

.vd-nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--vd-dark-alt);
  cursor: pointer;
}

/* Hero Section */
.vd-hero {
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0369a1 100%);
  color: var(--vd-white);
  padding: 5rem 0 4.5rem;
  position: relative;
  overflow: hidden;
}

.vd-hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 3.5rem;
  align-items: center;
}

.vd-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.35rem 0.85rem;
  border-radius: 9999px;
  background-color: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(8px);
  color: #38bdf8;
  margin-bottom: 1.25rem;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.vd-hero h1 {
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
}

.vd-hero p {
  font-size: 1.125rem;
  line-height: 1.7;
  color: #cbd5e1;
  margin-bottom: 2rem;
}

.vd-hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.vd-hero-image-card {
  position: relative;
  border-radius: var(--vd-radius-lg);
  overflow: hidden;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.vd-hero-image-card img {
  width: 100%;
  height: 380px;
  object-fit: cover;
  display: block;
}

.vd-hero-overlay-stats {
  position: absolute;
  bottom: 1rem;
  left: 1rem;
  right: 1rem;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(10px);
  padding: 1rem 1.25rem;
  border-radius: var(--vd-radius-md);
  border: 1px solid rgba(255, 255, 255, 0.15);
  display: flex;
  justify-content: space-around;
  text-align: center;
}

.vd-stat-val {
  font-weight: 800;
  font-size: 1.25rem;
  color: #38bdf8;
}

.vd-stat-lbl {
  font-size: 0.75rem;
  color: #94a3b8;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Section styling */
.vd-section {
  padding: 4.5rem 0;
}

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

.vd-section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 3.5rem;
}

.vd-section-tag {
  font-weight: 700;
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--vd-primary);
  margin-bottom: 0.5rem;
  display: block;
}

.vd-section-title {
  font-size: 2.125rem;
  font-weight: 800;
  color: var(--vd-dark);
  line-height: 1.3;
  margin-bottom: 1rem;
}

.vd-section-subtitle {
  font-size: 1.0625rem;
  color: var(--vd-muted);
}

/* Feature & Research Cards */
.vd-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.vd-card {
  background-color: var(--vd-white);
  border-radius: var(--vd-radius-lg);
  border: 1px solid var(--vd-border);
  overflow: hidden;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
}

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

.vd-card-img-wrapper {
  position: relative;
  height: 210px;
  overflow: hidden;
}

.vd-card-img-wrapper img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.3s ease;
}

.vd-card:hover .vd-card-img-wrapper img {
  transform: scale(1.04);
}

.vd-card-badge {
  position: absolute;
  top: 1rem;
  left: 1rem;
  background-color: rgba(15, 23, 42, 0.85);
  color: #38bdf8;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.65rem;
  border-radius: 9999px;
  backdrop-filter: blur(4px);
}

.vd-card-body {
  padding: 1.75rem;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

.vd-card-meta {
  font-size: 0.8125rem;
  color: var(--vd-muted);
  margin-bottom: 0.65rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.vd-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--vd-dark);
  line-height: 1.4;
  margin-bottom: 0.75rem;
}

.vd-card-title a {
  color: inherit;
  text-decoration: none;
}

.vd-card-title a:hover {
  color: var(--vd-primary);
}

.vd-card-text {
  font-size: 0.9375rem;
  color: var(--vd-slate);
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.vd-card-footer {
  padding-top: 1rem;
  border-top: 1px solid var(--vd-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.vd-author-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--vd-dark-alt);
}

/* Interactive Calculator Module */
.vd-calc-wrapper {
  background: linear-gradient(145deg, #ffffff 0%, #f1f5f9 100%);
  border-radius: var(--vd-radius-lg);
  border: 1px solid var(--vd-border-dark);
  padding: 2.5rem;
  box-shadow: var(--vd-shadow-md);
}

.vd-calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
}

.vd-calc-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.vd-form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.vd-form-label {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--vd-dark);
}

.vd-form-input,
.vd-form-select,
.vd-form-textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 0.9375rem;
  font-family: inherit;
  border: 1px solid var(--vd-border-dark);
  border-radius: var(--vd-radius-md);
  background-color: var(--vd-white);
  color: var(--vd-dark);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.vd-form-input:focus,
.vd-form-select:focus,
.vd-form-textarea:focus {
  outline: none;
  border-color: var(--vd-primary);
  box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.15);
}

.vd-calc-results {
  background-color: var(--vd-dark);
  color: var(--vd-white);
  border-radius: var(--vd-radius-md);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.vd-res-header {
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #38bdf8;
  margin-bottom: 0.5rem;
}

.vd-res-value {
  font-size: 2.5rem;
  font-weight: 800;
  color: #ffffff;
  line-height: 1.1;
  margin-bottom: 1rem;
}

.vd-res-breakdown {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid #334155;
}

.vd-res-item-lbl {
  font-size: 0.75rem;
  color: #94a3b8;
  text-transform: uppercase;
}

.vd-res-item-val {
  font-size: 1.125rem;
  font-weight: 700;
  color: #f1f5f9;
}

/* FAQ Accordion */
.vd-faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.vd-faq-item {
  background-color: var(--vd-white);
  border: 1px solid var(--vd-border);
  border-radius: var(--vd-radius-md);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.vd-faq-item.active {
  border-color: var(--vd-primary);
}

.vd-faq-question {
  padding: 1.25rem 1.5rem;
  font-weight: 700;
  font-size: 1.0625rem;
  color: var(--vd-dark);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.vd-faq-question i {
  color: var(--vd-primary);
  transition: transform 0.2s ease;
}

.vd-faq-item.active .vd-faq-question i {
  transform: rotate(180deg);
}

.vd-faq-answer {
  display: none;
  padding: 0 1.5rem 1.5rem;
  font-size: 0.9375rem;
  color: var(--vd-slate);
  line-height: 1.7;
}

.vd-faq-item.active .vd-faq-answer {
  display: block;
}

/* Page Banner */
.vd-page-banner {
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  color: var(--vd-white);
  padding: 3.5rem 0;
}

.vd-page-banner h1 {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
}

.vd-page-banner p {
  font-size: 1.125rem;
  color: #94a3b8;
  max-width: 700px;
}

/* Content Typography */
.vd-article-content {
  background-color: var(--vd-white);
  padding: 3rem;
  border-radius: var(--vd-radius-lg);
  border: 1px solid var(--vd-border);
  margin-bottom: 3rem;
}

.vd-article-content h2 {
  font-size: 1.625rem;
  font-weight: 800;
  color: var(--vd-dark);
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.vd-article-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--vd-dark-alt);
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

.vd-article-content p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--vd-slate);
  margin-bottom: 1.25rem;
}

.vd-article-content ul,
.vd-article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.vd-article-content li {
  margin-bottom: 0.5rem;
  color: var(--vd-slate);
  line-height: 1.7;
}

.vd-callout {
  background-color: var(--vd-primary-light);
  border-left: 4px solid var(--vd-primary);
  padding: 1.25rem 1.5rem;
  border-radius: 0 var(--vd-radius-md) var(--vd-radius-md) 0;
  margin: 1.75rem 0;
}

.vd-callout p {
  color: var(--vd-dark-alt);
  font-size: 0.9375rem;
  margin-bottom: 0;
}

/* Table */
.vd-table-responsive {
  overflow-x: auto;
  margin: 1.75rem 0;
}

.vd-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9375rem;
}

.vd-table th {
  background-color: var(--vd-dark);
  color: var(--vd-white);
  padding: 0.85rem 1rem;
  font-weight: 700;
}

.vd-table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--vd-border);
  color: var(--vd-slate);
}

.vd-table tr:nth-child(even) td {
  background-color: var(--vd-light);
}

/* Contact Grid */
.vd-contact-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 3rem;
}

.vd-contact-card {
  background-color: var(--vd-white);
  border-radius: var(--vd-radius-lg);
  border: 1px solid var(--vd-border);
  padding: 2.5rem;
  box-shadow: var(--vd-shadow-sm);
}

.vd-info-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.vd-info-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.vd-info-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--vd-radius-md);
  background-color: var(--vd-primary-light);
  color: var(--vd-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.125rem;
  flex-shrink: 0;
}

.vd-info-text h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--vd-dark);
  margin-bottom: 0.25rem;
}

.vd-info-text p {
  font-size: 0.9375rem;
  color: var(--vd-muted);
  line-height: 1.5;
}

.vd-map-container {
  border-radius: var(--vd-radius-lg);
  overflow: hidden;
  border: 1px solid var(--vd-border);
  height: 280px;
  margin-top: 1.5rem;
}

.vd-map-container iframe {
  width: 100%;
  height: 100%;
  border: 0;
}

/* Alert notifications */
.vd-alert {
  padding: 1rem 1.25rem;
  border-radius: var(--vd-radius-md);
  margin-bottom: 1.25rem;
  font-size: 0.9375rem;
  display: none;
}

.vd-alert-success {
  background-color: #dcfce7;
  color: #166534;
  border: 1px solid #86efac;
}

.vd-alert-error {
  background-color: #fee2e2;
  color: #991b1b;
  border: 1px solid #fca5a5;
}

/* Footer */
.vd-footer {
  background-color: var(--vd-dark);
  color: #94a3b8;
  padding-top: 4.5rem;
  margin-top: auto;
  border-top: 1px solid #1e293b;
}

.vd-footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 3rem;
  padding-bottom: 3.5rem;
  border-bottom: 1px solid #1e293b;
}

.vd-footer-col h4 {
  color: var(--vd-white);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
}

.vd-footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.vd-footer-links a {
  color: #94a3b8;
  text-decoration: none;
  font-size: 0.875rem;
  transition: color 0.2s ease;
}

.vd-footer-links a:hover {
  color: #38bdf8;
}

.vd-footer-desc {
  font-size: 0.875rem;
  line-height: 1.6;
  margin-top: 1rem;
  color: #64748b;
}

.vd-footer-bottom {
  padding: 1.75rem 0;
  font-size: 0.8125rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  color: #64748b;
}

/* Cookie Banner */
.vd-cookie-banner {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  max-width: 440px;
  background-color: var(--vd-white);
  border: 1px solid var(--vd-border-dark);
  border-radius: var(--vd-radius-lg);
  padding: 1.5rem;
  box-shadow: var(--vd-shadow-lg);
  z-index: 9999;
  display: none;
  animation: vdFadeIn 0.3s ease;
}

@keyframes vdFadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

.vd-cookie-banner h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--vd-dark);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.vd-cookie-banner p {
  font-size: 0.875rem;
  color: var(--vd-slate);
  margin-bottom: 1.25rem;
  line-height: 1.5;
}

.vd-cookie-actions {
  display: flex;
  gap: 0.75rem;
}

/* Responsive */
@media (max-width: 992px) {
  .vd-hero-grid,
  .vd-calc-grid,
  .vd-contact-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  
  .vd-footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
  }
}

@media (max-width: 768px) {
  .vd-nav-toggle {
    display: block;
  }
  
  .vd-nav-menu {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    width: 100%;
    background-color: var(--vd-white);
    flex-direction: column;
    align-items: flex-start;
    padding: 1.5rem;
    box-shadow: var(--vd-shadow-md);
    border-bottom: 1px solid var(--vd-border);
    gap: 1rem;
  }
  
  .vd-nav-menu.active {
    display: flex;
  }
  
  .vd-topbar-content {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .vd-hero h1 {
    font-size: 2rem;
  }
  
  .vd-footer-grid {
    grid-template-columns: 1fr;
  }
  
  .vd-cookie-banner {
    left: 1rem;
    right: 1rem;
    bottom: 1rem;
    max-width: none;
  }
}