/* ==========================================================================
   Sarfaraz Ahamed Shovon — Simple Portfolio Design System
   Design tokens sourced from DESIGN.md & SKILL.md
   ========================================================================== */

/* ── Google Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;600;700&display=swap');

/* ── Design Tokens ── */
:root {
  --font-family-primary: 'Open Sans', sans-serif;
  --font-size-base: 17.3333px; /* 13pt */
  --font-size-sm: 14px;
  --font-size-md: 16px;
  --font-size-lg: 24px;
  --font-size-xl: 32px; /* For main titles */
  
  --font-weight-base: 400;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --line-height-base: 27.7333px;
  
  --color-text-primary: #212121;
  --color-text-secondary: #555555;
  --color-surface-base: #ffffff;
  --color-surface-raised: #f8f9fa;
  --color-surface-strong: #000000;
  
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 32px;
  --space-6: 48px;
  --space-7: 64px;

  --container-max: 1200px;
}

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

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-base);
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-surface-base);
  -webkit-font-smoothing: antialiased;
  overflow-y: scroll; /* Force vertical scrollbar to prevent layout shift between pages */
}

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

a:hover {
  text-decoration: underline;
}

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

/* ── Layout ── */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

/* ── Header / Navigation ── */
.header {
  padding: var(--space-4) 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: nowrap; /* Prevent wrapping so search stays on right */
  gap: var(--space-4);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.mobile-menu-btn {
  display: none;
  font-size: 20px;
  color: var(--color-text-primary);
  cursor: pointer;
}

.site-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  white-space: nowrap; /* Prevent title from wrapping to multiple lines */
}

.nav {
  display: flex;
  align-items: center;
  flex-grow: 1;
  justify-content: flex-end;
}

.nav-links {
  display: flex;
  gap: var(--space-3);
  align-items: center;
  flex-wrap: nowrap; /* Keep all tabs on one line */
}

.close-menu-btn {
  display: none;
}

.menu-overlay {
  display: none;
}

.nav-link {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  padding: var(--space-1) var(--space-2);
  border-radius: 4px;
  transition: all 0.2s ease;
}

.nav-link:hover {
  color: var(--color-text-primary);
  text-decoration: none;
}

.nav-link.active {
  background-color: var(--color-surface-strong);
  color: var(--color-surface-base);
}

.nav-search {
  margin-left: var(--space-2);
  color: var(--color-text-primary);
  cursor: pointer;
  font-size: 20px;
}

/* ── Main Content Area ── */
.main-content {
  padding: var(--space-5) 0;
}

/* ── Hero Section ── */
.hero {
  display: flex;
  gap: var(--space-6);
  align-items: flex-start;
  margin-bottom: var(--space-7);
}

.hero-image {
  flex-shrink: 0;
  width: 300px;
}

.hero-image img {
  width: 100%;
  border-radius: 8px; /* Slight rounding for a clean look */
}

.hero-info {
  flex-grow: 1;
}

.hero-name {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-4);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.hero-details p {
  color: var(--color-text-primary);
}

.hero-title {
  margin-bottom: var(--space-5);
}

.hero-affiliation {
  margin-bottom: var(--space-3);
}

.hero-affiliation p {
  color: #1a4b8c;
  margin-bottom: 2px;
}

/* ── Resume Button ── */
.btn-resume {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  background-color: #ffffff;
  color: #212121 !important;
  font-size: 14px;
  font-weight: 600;
  border: 1px solid #333333;
  border-radius: 4px;
  text-decoration: none;
  transition: all 0.2s ease;
}

.btn-resume:hover {
  background-color: #212121;
  color: #ffffff !important;
  text-decoration: none;
  border-color: #212121;
}

.social-icons a:hover {
  transform: translateY(-2px);
  opacity: 0.9;
  text-decoration: none;
  color: #ffffff;
}

/* ── Sections ── */
.section {
  margin-bottom: var(--space-7);
  padding-left: var(--space-5); /* Indent sections slightly as seen in reference */
}

.section-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-4);
  color: var(--color-text-primary);
}

/* ── Text Content ── */
.content-text {
  margin-bottom: var(--space-3);
  text-align: justify;
}

.content-text p {
  margin-bottom: var(--space-4); /* Added paragraph spacing */
}

/* ── Lists ── */
.experience-list, .awards-list {
  list-style-type: square;
  padding-left: var(--space-4);
}

.experience-item, .award-item {
  margin-bottom: var(--space-5);
}

.experience-item strong, .award-item strong {
  display: block;
  font-size: var(--font-size-md);
  margin-bottom: var(--space-2);
}

.experience-details {
  list-style-type: disc;
  padding-left: var(--space-4);
  margin-top: var(--space-2);
  margin-bottom: var(--space-2);
}

.experience-details li {
  margin-bottom: var(--space-1);
}

/* ── Contact Info ── */
.contact-info p {
  margin-bottom: var(--space-2);
}

.contact-info p:first-child {
  margin-bottom: var(--space-4);
}

/* ── Social Icons ── */
.social-icons {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.social-icons a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  color: #ffffff;
  font-size: 20px;
  transition: all 0.3s ease;
}

.social-icons a[aria-label="Facebook"] {
  background-color: #1877F2;
}

.social-icons a[aria-label="GitHub"] {
  background-color: #333333;
}

.social-icons a[aria-label="LinkedIn"] {
  background-color: #0A66C2;
}

.social-icons a[aria-label="Google Scholar"] {
  background-color: #4285F4;
}

.social-icon:hover {
  opacity: 0.8;
  text-decoration: none;
}

.icon-facebook { background-color: #1877F2; }
.icon-github { background-color: #333333; }
.icon-linkedin { background-color: #0A66C2; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .nav {
    position: fixed;
    top: 0;
    left: -280px;
    width: 280px;
    height: 100vh;
    background-color: var(--color-surface-raised);
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
    padding: var(--space-4) 0;
    z-index: 1000;
    transition: left 0.3s ease;
    box-shadow: 2px 0 5px rgba(0,0,0,0.1);
  }
  
  .nav.open {
    left: 0;
  }
  
  .nav-links {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
    width: 100%;
  }

  .nav-link {
    font-size: var(--font-size-md);
    padding: var(--space-2) var(--space-4);
    width: 100%;
  }
  
  .nav-link.active {
    display: inline-block;
    align-self: flex-start;
    margin-left: var(--space-4);
    padding: 4px 8px;
    border-radius: 2px;
    width: auto;
  }
  
  .close-menu-btn {
    display: block;
    align-self: flex-start;
    margin-left: var(--space-4);
    margin-bottom: var(--space-4);
    font-size: 20px;
    cursor: pointer;
    color: var(--color-text-secondary);
  }

  .menu-overlay {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
  }
  
  .menu-overlay.open {
    opacity: 1;
    pointer-events: auto;
  }
  
  .mobile-menu-btn {
    display: block; /* Show hamburger on mobile */
  }
  
  .header {
    gap: var(--space-2);
  }

  .header-brand {
    gap: var(--space-2);
  }

  .site-title {
    font-size: 16px;
    white-space: normal;
    line-height: 1.3;
  }
  
  .hero {
    flex-direction: column;
    align-items: flex-start; /* Keep text left-aligned */
    gap: var(--space-5);
  }
  
  .hero-image {
    width: 100%;
    max-width: none; /* Let it stretch fully */
  }
  
  .hero-image img {
    border-radius: 0; /* Remove rounded corners on mobile to match reference */
    width: 100%;
  }
  
  .hero-info {
    width: 100%;
    text-align: left; /* Keep text left-aligned */
  }
  
  .hero-name {
    font-size: var(--font-size-lg);
  }
  
  h3.project-title, .project-title {
    font-size: 15px !important;
    line-height: 1.35 !important;
    margin-bottom: 12px !important;
  }
  
  .academic-card {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .academic-image {
    width: 100%;
  }

  .academic-details {
    width: 100%;
    text-align: left;
  }

  .section {
    padding-left: 0;
  }
  
  .social-icons {
    justify-content: flex-start;
  }
}

/* ── Academic Background ── */
.academic-card {
  display: flex;
  gap: var(--space-5);
  margin-bottom: var(--space-5);
  align-items: center;
}

.academic-image {
  flex: 0 0 45%; /* Image takes about 45% of the width */
}

.academic-image img {
  width: 100%;
  aspect-ratio: 16 / 9; /* Standardized size for all images */
  object-fit: cover;
  border-radius: 4px;
}

.academic-details {
  flex: 1;
}

.degree-title {
  font-size: var(--font-size-lg); /* Increased font size */
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  margin-bottom: var(--space-3);
}

.academic-details p {
  margin-bottom: var(--space-2);
  color: var(--color-text-primary);
}

/* ── Projects ── */
.project-card {
  text-align: center;
  margin-bottom: var(--space-7);
}

.project-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-4);
  color: var(--color-text-primary);
}

.text-left {
  text-align: left;
  margin-left: 5%;
}

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

.project-links {
  margin-bottom: var(--space-5);
}

.project-link {
  display: inline-block;
  margin: 0 var(--space-2);
  color: #1a4b8c;
  font-weight: var(--font-weight-bold);
  text-decoration: underline;
  text-transform: uppercase;
}

.project-link:hover {
  color: #0A66C2;
}

.carousel-container {
  position: relative;
  max-width: 650px;
  margin: var(--space-5) auto;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.carousel-container.fixed-ratio {
  aspect-ratio: 16 / 9;
  background-color: #f8f9fa;
}

.carousel-container.fixed-ratio .carousel-track {
  height: 100%;
}

.carousel-container.fixed-ratio .carousel-img {
  height: 100%;
}

.carousel-container.fixed-ratio .carousel-img.active {
  position: absolute;
}

.carousel-mobile {
  max-width: 350px;
}

.carousel-track.fade-carousel {
  position: relative;
  display: block;
  overflow: hidden;
  width: 100%;
}

.carousel-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  opacity: 0;
  transition: opacity 0.8s ease-in-out;
  background-color: #ffffff;
}

.carousel-img.active {
  opacity: 1;
  z-index: 1;
  position: relative;
  height: auto;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(0, 0, 0, 0.6);
  color: white;
  border: none;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.3s;
  z-index: 2;
}

.carousel-btn:hover {
  background: rgba(0, 0, 0, 0.9);
}

.prev-btn { left: 10px; }
.next-btn { right: 10px; }

.project-actions {
  margin-top: var(--space-4);
}