:root {
  /* Primary colors */
  --color-bg: #ffffff;            /* Page background */
  --color-text-primary: #111111;  /* Main body text */
  --color-text-secondary: #555555; /* Subheadings, subtitles, italic text */
  --color-link: #0066cc;          /* Link color */
  --color-link-hover: #004499;    /* Link hover color */
  --color-header-bg: var(--color-bg); /* Header background (none in this design) */
  --color-header-text: var(--color-text-primary);
  --color-section-heading: #555555; /* Research heading color */
}

/* Base styles */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  background-color: var(--color-bg);
  color: var(--color-text-primary);
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 18px;
  line-height: 1.6;
  display: flex;
  justify-content: center;   /* horizontal centering */
  align-items: center;       /* vertical centering */
  min-height: 100vh;
  flex-wrap: wrap;      /* allow wrapping on small widths */
  min-width: 0;         /* prevent content overflow */
}

main {
  max-width: 700px;
  width: 90vw;           /* allows main to shrink with viewport */
  padding: 60px 20px;
  margin: 0;
  box-sizing: border-box; /* include padding inside width */
  opacity: 1;
}

/* Typography and spacing */
.header-container {
  display: flex;
  align-items: center;  /* vertically center image with text */
  justify-content: space-between; /* dynamic space */
  width: 100%; /* ensure it fills the container */
  margin-bottom: 2rem;
}

.title {
  font-size: 2.5rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
  opacity: 0;
  color: var(--color-text-primary);
}

.subtitle {
  font-size: 1.25rem;
  margin-bottom: 1.5rem;
  color: var(--color-text-secondary);
  opacity: 0;
}

.intro {
  margin-bottom: 1rem;
  opacity: 0;
  color: var(--color-text-primary);
}

.location {
  margin-bottom: 3rem;
  font-style: italic;
  color: var(--color-text-secondary);
  opacity: 0;
}

.research {
  margin-bottom: 3rem;
  opacity: 0;
}

.research h2 {
  color: var(--color-section-heading);
  margin-bottom: 1rem;
}

.research ul {
  list-style-type: disc;
  padding-left: 20px;
  color: var(--color-text-primary);
}

.research li {
  margin-bottom: 0.5rem;
}

.research a {
  color: var(--color-link);
  text-decoration: none;
}

.research a:hover {
  color: var(--color-link-hover);
  text-decoration: underline;
}

.links {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  opacity: 0;
}

.links a {
  color: var(--color-link);
  text-decoration: none;
  font-weight: bold;
}

.links a:hover {
  color: var(--color-link-hover);
  text-decoration: underline;
}

/* Profile picture styling */
.profile-pic {
  width: 6em;
  height: 6em;
  border-radius: 50%;       /* makes the image circular */
  object-fit: cover;        /* crop to fit the circle */
  box-shadow: 0 0 8px rgba(0,0,0,0.1); /* optional subtle shadow */
}

/* Animation */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(15px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation-name: fadeInUp;
  animation-fill-mode: forwards;
  animation-duration: 600ms;
  animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
}

/* Responsiveness Adjustments */
@media (max-width: 600px) {
  html, body {
    font-size: 16px;  /* Slightly smaller base font on mobile */
  }

  main {
    padding: 40px 15px;
    max-width: 90vw;
  }
  
  .title {
    font-size: 2rem;
  }
  
  /* Left-align research list items on mobile for readability */
  .research ul {
    padding-left: 20px;
    list-style-position: outside;
    text-align: left;
    margin: 0 auto;
    max-width: 400px; /* keep list narrower for readability */
  }

  nav.links {
    justify-content: center;
  }

   .header-container {
    flex-direction: column;  /* stack image above text */
    align-items: center;     /* center content */
    gap: 10px;               /* reduce spacing on mobile */
  }

  .profile-pic {
    order: -1;                /* move image above the text */
  }

  .subtitle {
    margin-bottom: 0rem;
  }
}