/* ============================================
   Bahnsen Learning Design — Design System
   Modern, Minimalist, Airy & Warm
   ============================================ */

/* ---------- CSS Custom Properties ---------- */
:root {
  /* Colors */
  --color-primary: #2B6CB0;
  --color-primary-dark: #1E4F85;
  --color-primary-light: #3B82C4;
  --color-blue-50: #EBF4FF;
  --color-blue-100: #D1E6FA;
  --color-accent: #F6C744;
  --color-accent-dark: #D9A825;
  --color-accent-light: #FEF9E7;
  --color-text: #2D3748;
  --color-text-light: #718096;
  --color-text-inverse: #FFFFFF;
  --color-bg: #FFFFFF;
  --color-bg-alt: #F7FAFC;
  --color-bg-warm: #FEF9E7;
  --color-border: #E2E8F0;
  --color-overlay: rgba(43, 108, 176, 0.85);

  /* Typography */
  --font-heading: 'Nunito', sans-serif;
  --font-body: 'Inter', sans-serif;
  --fs-hero: clamp(2.2rem, 5vw, 3.5rem);
  --fs-h1: clamp(1.8rem, 4vw, 2.5rem);
  --fs-h2: clamp(1.4rem, 3vw, 2rem);
  --fs-h3: clamp(1.1rem, 2vw, 1.35rem);
  --fs-body: 1rem;
  --fs-small: 0.875rem;
  --fs-xs: 0.75rem;
  --line-height: 1.7;
  --line-height-heading: 1.3;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;

  /* Layout */
  --max-width: 1200px;
  --max-width-narrow: 800px;
  --nav-height: 72px;
  --border-radius: 12px;
  --border-radius-sm: 8px;

  /* Effects */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 4px 20px rgba(246, 199, 68, 0.3);
  --transition: 0.3s ease;
  --transition-slow: 0.5s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: var(--line-height-heading);
  color: var(--color-text);
}

h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }

p + p {
  margin-top: var(--space-sm);
}

/* ---------- Utility Classes ---------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.container--narrow {
  max-width: var(--max-width-narrow);
}

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

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

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

.section--blue {
  background-color: var(--color-blue-50);
}

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

.text-light {
  color: var(--color-text-light);
}

.section-title {
  font-size: var(--fs-h2);
  margin-bottom: var(--space-xs);
}

.section-subtitle {
  font-size: var(--fs-body);
  color: var(--color-text-light);
  max-width: 600px;
  margin-bottom: var(--space-xl);
}

.text-center .section-subtitle {
  margin-left: auto;
  margin-right: auto;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: var(--border-radius-sm);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  line-height: 1;
}

.btn--primary {
  background-color: var(--color-accent);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
}

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

.btn--outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn--outline:hover {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  transform: translateY(-2px);
}

.btn--white {
  background-color: var(--color-bg);
  color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.btn--white:hover {
  background-color: var(--color-blue-50);
  color: var(--color-primary-dark);
  transform: translateY(-2px);
}

.btn--small {
  padding: 0.5rem 1.25rem;
  font-size: var(--fs-small);
}

.btn--icon {
  padding: 0.6rem;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  justify-content: center;
}

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

.navbar.scrolled {
  box-shadow: var(--shadow-sm);
}

.navbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.navbar__logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
}

.navbar__logo img,
.navbar__logo svg {
  height: 40px;
  width: auto;
}

.navbar__links {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  list-style: none;
}

.navbar__links a {
  font-family: var(--font-body);
  font-size: var(--fs-small);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  padding: 0.25rem 0;
  position: relative;
  transition: color var(--transition);
}

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

.navbar__links a:hover,
.navbar__links a.active {
  color: var(--color-primary);
}

.navbar__links a:hover::after,
.navbar__links a.active::after {
  width: 100%;
}

.navbar__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.navbar__toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: all var(--transition);
  border-radius: 2px;
}

/* ---------- Hero Section ---------- */
.hero {
  position: relative;
  min-height: 85vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--nav-height) + var(--space-xl)) var(--space-md) var(--space-xl);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.hero__bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(43, 108, 176, 0.88) 0%, rgba(30, 79, 133, 0.92) 100%);
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: 750px;
}

.hero__title {
  font-size: var(--fs-hero);
  color: var(--color-text-inverse);
  margin-bottom: var(--space-md);
  font-weight: 800;
}

.hero__title span {
  color: var(--color-accent);
}

.hero__subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: var(--space-lg);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.8;
}

.hero__actions {
  display: flex;
  gap: var(--space-sm);
  justify-content: center;
  flex-wrap: wrap;
}

/* Page Hero (smaller, for inner pages) */
.page-hero {
  padding: calc(var(--nav-height) + var(--space-xl)) 0 var(--space-xl);
  text-align: center;
  background: linear-gradient(135deg, var(--color-blue-50) 0%, var(--color-bg) 100%);
}

.page-hero__title {
  font-size: var(--fs-h1);
  margin-bottom: var(--space-xs);
}

.page-hero__subtitle {
  color: var(--color-text-light);
  max-width: 500px;
  margin: 0 auto;
}

/* ---------- Cards ---------- */
.card {
  background: var(--color-bg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: all var(--transition);
}

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

.card__image {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background-color: var(--color-blue-50);
}

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

.card__badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-xs);
}

.card__badge--interactive {
  background-color: var(--color-blue-50);
  color: var(--color-primary);
}

.card__badge--video {
  background-color: var(--color-accent-light);
  color: var(--color-accent-dark);
}

.card__badge--document {
  background-color: #F0FFF4;
  color: #276749;
}

.card__title {
  font-size: var(--fs-h3);
  margin-bottom: var(--space-xs);
}

.card__description {
  font-size: var(--fs-small);
  color: var(--color-text-light);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.card__footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

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

.portfolio-filters {
  display: flex;
  gap: var(--space-xs);
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: var(--space-xl);
}

.filter-btn {
  padding: 0.5rem 1.25rem;
  border: 2px solid var(--color-border);
  border-radius: 25px;
  background: var(--color-bg);
  color: var(--color-text-light);
  font-family: var(--font-body);
  font-size: var(--fs-small);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}

.filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.filter-btn.active {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* ---------- About Section ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--space-xl);
  align-items: start;
}

.about-image {
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-md);
  width: 100%;
  object-fit: cover;
}

.about-content h2 {
  margin-bottom: var(--space-md);
}

.about-content p {
  color: var(--color-text-light);
  margin-bottom: var(--space-sm);
}

/* Skills Grid */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-md);
}

.skill-card {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  border-radius: var(--border-radius-sm);
  background: var(--color-bg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.skill-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.skill-card__icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--color-blue-50);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.skill-card__icon svg {
  width: 22px;
  height: 22px;
  stroke: var(--color-primary);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.skill-card__name {
  font-size: var(--fs-small);
  font-weight: 600;
}

/* ---------- Process / Timeline ---------- */
.process-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-lg);
  position: relative;
}

.process-step {
  text-align: center;
  padding: var(--space-lg) var(--space-md);
  border-radius: var(--border-radius);
  background: var(--color-bg);
  box-shadow: var(--shadow-sm);
  position: relative;
  transition: all var(--transition);
}

.process-step:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.process-step__number {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  color: var(--color-text-inverse);
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-md);
}

.process-step__title {
  font-size: var(--fs-h3);
  margin-bottom: var(--space-xs);
  color: var(--color-primary);
}

.process-step__description {
  font-size: var(--fs-small);
  color: var(--color-text-light);
  line-height: 1.6;
}

/* ---------- Intro / Feature Section ---------- */
.intro-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-lg);
  align-items: center;
}

.intro-image {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--color-accent);
}

.intro-text p {
  color: var(--color-text-light);
  font-size: 1.05rem;
}

/* Featured Work */
.featured-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-lg);
}

/* ---------- CTA Banner ---------- */
.cta-banner {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  padding: var(--space-xl) var(--space-md);
  text-align: center;
  border-radius: var(--border-radius);
  color: var(--color-text-inverse);
}

.cta-banner h2 {
  color: var(--color-text-inverse);
  margin-bottom: var(--space-xs);
}

.cta-banner p {
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: var(--space-lg);
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--space-xl);
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.contact-item__icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--color-blue-50);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-item__icon svg {
  width: 20px;
  height: 20px;
  stroke: var(--color-primary);
  fill: none;
  stroke-width: 2;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.form-group label {
  font-size: var(--fs-small);
  font-weight: 600;
  color: var(--color-text);
}

.form-group input,
.form-group textarea {
  padding: 0.75rem 1rem;
  border: 2px solid var(--color-border);
  border-radius: var(--border-radius-sm);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  color: var(--color-text);
  transition: border-color var(--transition);
  background: var(--color-bg);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(43, 108, 176, 0.1);
}

.form-group textarea {
  min-height: 150px;
  resize: vertical;
}

/* ---------- Video Modal ---------- */
.video-modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: rgba(0, 0, 0, 0.85);
  align-items: center;
  justify-content: center;
  padding: var(--space-md);
}

.video-modal.active {
  display: flex;
}

.video-modal__content {
  max-width: 900px;
  width: 100%;
  position: relative;
}

.video-modal__close {
  position: absolute;
  top: -40px;
  right: 0;
  background: none;
  border: none;
  color: white;
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.5rem;
}

.video-modal video {
  width: 100%;
  border-radius: var(--border-radius-sm);
}

/* ---------- Footer ---------- */
.footer {
  background-color: var(--color-text);
  color: rgba(255, 255, 255, 0.7);
  padding: var(--space-xl) 0 var(--space-lg);
}

.footer__inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

.footer__brand p {
  margin-top: var(--space-sm);
  font-size: var(--fs-small);
  line-height: 1.7;
  max-width: 300px;
}

.footer__nav h4,
.footer__social h4 {
  color: var(--color-text-inverse);
  font-size: var(--fs-body);
  margin-bottom: var(--space-sm);
}

.footer__nav ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.footer__nav a {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--fs-small);
  transition: color var(--transition);
}

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

.footer__social-links {
  display: flex;
  gap: var(--space-sm);
}

.footer__social-link {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
}

.footer__social-link:hover {
  background: var(--color-accent);
}

.footer__social-link svg {
  width: 18px;
  height: 18px;
  fill: white;
}

.footer__bottom {
  padding-top: var(--space-lg);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: var(--fs-small);
}

/* Logo in footer - white version */
.footer .navbar__logo svg .logo-text {
  fill: white;
}

/* ---------- Fade-in Animation ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

  .about-image {
    max-width: 350px;
    margin: 0 auto;
  }

  .footer__inner {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .navbar__links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: var(--space-md);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    transform: translateY(-120%);
    transition: transform var(--transition);
    gap: var(--space-xs);
  }

  .navbar__links.open {
    transform: translateY(0);
  }

  .navbar__links a {
    display: block;
    padding: var(--space-xs) 0;
    font-size: var(--fs-body);
  }

  .navbar__toggle {
    display: flex;
  }

  .navbar__toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .navbar__toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .navbar__toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  .hero {
    min-height: 70vh;
    padding-top: calc(var(--nav-height) + var(--space-lg));
  }

  .portfolio-grid {
    grid-template-columns: 1fr;
  }

  .featured-grid {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .process-steps {
    grid-template-columns: 1fr;
  }

  .intro-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .intro-image {
    margin: 0 auto;
  }

  .footer__inner {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer__brand p {
    max-width: none;
  }

  .footer__social-links {
    justify-content: center;
  }

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

@media (max-width: 480px) {
  .hero__actions {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }

  .portfolio-filters {
    gap: 0.35rem;
  }

  .filter-btn {
    padding: 0.4rem 0.9rem;
    font-size: var(--fs-xs);
  }

  .skills-grid {
    grid-template-columns: 1fr;
  }
}