/* =======================
   Layout and Grid System
   ======================= */

/* Container centers content and limits max width */
.container {
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  /* Responsive side padding for small screens */
  padding-left: max(1rem, 5vw);
  padding-right: max(1rem, 5vw);
}

/* Flexbox utility classes for common layouts */
.flex {
  display: flex;
}

.flex-center {
  justify-content: center;
  align-items: center;
}

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

.flex-space-between {
  justify-content: space-between;
}

/* Navigation menu styles */
nav ul#nav-links {
  display: flex;
  gap: 1.25rem;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  /* Enable smooth fade in/out for mobile menu */
  opacity: 1;
  visibility: visible;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

/* Hidden state for mobile nav menu */
nav ul#nav-links.hide {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

nav ul#nav-links li {
  margin: 0;
}

/* Hamburger menu button hidden on desktop */
#mobile-menu-toggle {
  display: none;
  font-size: 1.5rem;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-color);
  z-index: 1001; /* Ensure button is above other elements */
  padding: 0.5rem; /* Larger tap target on mobile */
  border-radius: 4px;
  transition: background-color 0.2s ease;
}

#mobile-menu-toggle:hover,
#mobile-menu-toggle:focus-visible {
  background-color: var(--border-color);
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Mobile navigation styles and toggle */
@media (max-width: 768px) {
  #mobile-menu-toggle {
    display: inline-block; /* Show hamburger button */
  }

  nav ul#nav-links {
    flex-direction: column;
    background-color: var(--bg-color);
    position: absolute;
    top: 60px;
    right: 0;
    width: 200px;
    border: 1px solid var(--border-color);
    padding: 1rem;
    border-radius: 8px;
    opacity: 0;
    visibility: hidden;
    z-index: 999;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  }

  nav ul#nav-links.show {
    opacity: 1;
    visibility: visible;
  }
}

/* Section vertical spacing */
section {
  padding: 1.5rem 0;
}

/* Timeline visual styling */
.timeline {
  border-left: 3px solid var(--primary-color);
  margin-left: 1rem;
  padding-left: 1rem;
}

.timeline li {
  margin-bottom: 1.5rem;
}

/* Card container styling with shadow and rounded corners */
.card {
  background-color: var(--bg-color);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.05);
  margin-bottom: 1.5rem;
  /* Smooth shadow and movement on interaction */
  transition: box-shadow 0.3s ease, transform 0.3s ease;
}

.card:hover,
.card:focus-within {
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  transform: translateY(-3px);
  outline: none;
}

/* Inline button style */
.btn-inline {
  display: inline-block;
  background-color: var(--button-bg);
  color: var(--button-color);
  padding: 0.4rem 0.8rem;
  border-radius: 4px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: background-color 0.3s ease;
  text-decoration: none;
  user-select: none; /* Prevent text selection on click */
  outline: none;
}

.btn-inline:hover,
.btn-inline:focus-visible {
  background-color: var(--highlight-color);
  outline: 3px solid var(--highlight-color);
  outline-offset: 2px;
}

.btn-inline:focus {
  outline: none; /* Hide outline for mouse users */
}

/* Profile image circle with shadow and transition */
.profile-photo {
  width: 160px;
  height: 160px;
  object-fit: cover;
  border-radius: 50%;
  display: block;
  margin: 1rem auto;
  box-shadow: 0 0 8px rgba(0,0,0,0.2);
  transition: box-shadow 0.3s ease;
}

.profile-photo:hover,
.profile-photo:focus-visible {
  box-shadow: 0 0 12px rgba(0,0,0,0.35);
  outline: 2px solid var(--primary-color);
  outline-offset: 3px;
}

/* Smooth scrolling for anchor links and back-to-top */
html {
  scroll-behavior: smooth;
}

/* Responsive styles for small screens */
@media (max-width: 600px) {
  nav ul#nav-links {
    flex-direction: column;
    gap: 1rem;
  }

  nav {
    flex-direction: row !important;
    justify-content: space-between;
    align-items: center;
    gap: 0.75rem;
  }

  h1.logo {
    font-size: 1rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    flex-grow: 1;
  }

  #mobile-menu-toggle,
  #theme-toggle {
    font-size: 1.25rem;
    padding: 0.5rem; /* Larger tappable area */
    margin-left: 0.5rem;
    border-radius: 4px;
  }

  #mobile-menu-toggle {
    order: 1;
  }

  #theme-toggle {
    order: 2;
  }

  #theme-toggle:hover,
  #theme-toggle:focus-visible {
    background-color: var(--border-color);
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
  }

  .profile-photo {
    width: 120px;
    height: 120px;
  }
}