/* ==========================================
   Gregory F. Veramendi - Academic Website
   Modern Responsive Stylesheet
   ========================================== */

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

/* CSS Variables - Design System */
:root {
  /* Colors */
  --color-primary: #1a365d;
  --color-secondary: #2b6cb0;
  --color-accent: #3182ce;
  --color-text: #2d3748;
  --color-text-light: #4a5568;
  --color-text-muted: #718096;
  --color-bg: #f7fafc;
  --color-white: #ffffff;
  --color-border: #e2e8f0;
  --color-border-light: #edf2f7;

  /* Typography */
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Source Sans Pro', Georgia, 'Times New Roman', serif;
  --font-mono: 'SF Mono', Monaco, 'Courier New', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Layout */
  --max-width: 900px;
  --nav-height: 60px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.1), 0 2px 4px rgba(0, 0, 0, 0.06);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;
}

/* Base Styles */
html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-primary);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; margin-bottom: var(--space-md); }
h3 { font-size: 1.25rem; }

p {
  margin-bottom: var(--space-md);
}

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

a:hover {
  color: var(--color-accent);
  text-decoration: underline;
}

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

/* Navigation */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  height: var(--nav-height);
}

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

.nav-brand {
  font-family: var(--font-heading);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
}

.nav-brand:hover {
  text-decoration: none;
  color: var(--color-secondary);
}

.nav-links {
  display: flex;
  gap: var(--space-lg);
  list-style: none;
}

.nav-links a {
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-light);
  text-decoration: none;
  padding: var(--space-sm) 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-secondary);
  text-decoration: none;
}

.nav-links a.active {
  border-bottom-color: var(--color-secondary);
}

/* Mobile Navigation */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  margin: 5px 0;
  transition: var(--transition-fast);
}

/* Main Content */
main {
  padding: var(--space-2xl) 0;
  min-height: calc(100vh - var(--nav-height) - 100px);
}

/* Profile Section (Homepage) */
.profile {
  display: flex;
  gap: var(--space-2xl);
  align-items: flex-start;
  margin-bottom: var(--space-2xl);
}

.profile-photo {
  flex-shrink: 0;
}

.profile-photo img {
  width: 220px;
  height: auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
}

.profile-info {
  flex: 1;
}

.profile-name {
  font-size: 2rem;
  margin-bottom: var(--space-sm);
}

.profile-title {
  font-size: 1.1rem;
  color: var(--color-text-light);
  margin-bottom: var(--space-xs);
}

.profile-affiliation {
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
}

.profile-roles {
  margin-bottom: var(--space-lg);
}

.profile-roles h3 {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: var(--space-sm);
}

.profile-roles ul {
  list-style: none;
  color: var(--color-text-light);
}

.profile-roles li {
  margin-bottom: var(--space-xs);
}

.profile-links {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.profile-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  color: var(--color-text);
  transition: all var(--transition-fast);
}

.profile-link:hover {
  background: var(--color-secondary);
  border-color: var(--color-secondary);
  color: var(--color-white);
  text-decoration: none;
}

/* Section Styling */
.section {
  margin-bottom: var(--space-2xl);
}

.section-title {
  font-size: 1.25rem;
  color: var(--color-primary);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-border);
}

/* Paper Cards */
.paper-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin-bottom: var(--space-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition-normal);
}

.paper-card:hover {
  box-shadow: var(--shadow-lg);
}

.paper-title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.paper-title a {
  color: var(--color-primary);
}

.paper-title a:hover {
  color: var(--color-secondary);
}

.paper-authors {
  font-size: 0.95rem;
  color: var(--color-text-light);
  margin-bottom: var(--space-sm);
}

.paper-authors a {
  color: var(--color-secondary);
}

.paper-authors a:hover {
  color: var(--color-accent);
  text-decoration: underline;
}

.paper-venue {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

.paper-venue em {
  font-style: italic;
}

.paper-venue strong {
  font-weight: 600;
}

.paper-status {
  display: inline-block;
  padding: var(--space-xs) var(--space-sm);
  background: #f0fff4;
  color: #276749;
  font-size: 0.8rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  margin-left: var(--space-sm);
}

.paper-status.revision {
  background: #fffaf0;
  color: #c05621;
}

.paper-status.submitted {
  background: #ebf8ff;
  color: #2b6cb0;
}

.paper-actions {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  margin-bottom: var(--space-sm);
}

.paper-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-sm);
  font-size: 0.85rem;
  color: var(--color-secondary);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.paper-btn:hover {
  background: var(--color-secondary);
  border-color: var(--color-secondary);
  color: var(--color-white);
  text-decoration: none;
}

.abstract-toggle {
  font-family: var(--font-body);
}

.paper-abstract {
  display: none;
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border-light);
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--color-text-light);
}

.paper-abstract.show {
  display: block;
}

/* Topic Filters */
.filters {
  margin-bottom: var(--space-xl);
}

.filters-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.filter-buttons {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.filter-btn {
  padding: var(--space-sm) var(--space-md);
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-secondary);
  background: transparent;
  border: 2px solid var(--color-secondary);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  background: var(--color-secondary);
  color: var(--color-white);
}

.filter-btn.active {
  background: var(--color-secondary);
  color: var(--color-white);
}

.paper-count {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-top: var(--space-sm);
}

/* Papers List */
.papers-list {
  display: flex;
  flex-direction: column;
}

.paper-card[data-visible="false"] {
  display: none;
}

/* Featured Papers (Homepage) */
.featured-papers {
  display: grid;
  gap: var(--space-md);
}

.featured-paper {
  background: var(--color-white);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition-normal);
}

.featured-paper:hover {
  box-shadow: var(--shadow-lg);
}

/* Page Header */
.page-header {
  margin-bottom: var(--space-xl);
}

.page-title {
  font-size: 2rem;
  margin-bottom: var(--space-sm);
}

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

/* Section Divider */
.section-divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-2xl) 0;
}

/* Teaching Page */
.teaching-section {
  margin-bottom: var(--space-xl);
}

.teaching-institution {
  font-size: 1.1rem;
  color: var(--color-primary);
  margin-bottom: var(--space-md);
}

.teaching-list {
  list-style: none;
}

.teaching-item {
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.teaching-item:last-child {
  border-bottom: none;
}

.teaching-course {
  font-weight: 500;
}

.teaching-years {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Footer */
.footer {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* Google Scholar Link */
.scholar-link {
  margin-bottom: var(--space-lg);
}

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.25rem; }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-white);
    flex-direction: column;
    padding: var(--space-md);
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }

  .nav-links.show {
    display: flex;
  }

  .nav-links a {
    padding: var(--space-md);
    border-bottom: none;
  }

  .nav-toggle {
    display: block;
  }

  .profile {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .profile-photo img {
    width: 150px;
  }

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

  .container {
    padding: 0 var(--space-md);
  }

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

  .filter-buttons {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  h1 { font-size: 1.5rem; }

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

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

  .paper-title {
    font-size: 1rem;
  }

  .profile-links {
    flex-direction: column;
    align-items: stretch;
  }

  .profile-link {
    justify-content: center;
  }
}

/* Print Styles */
@media print {
  .nav,
  .filter-buttons,
  .abstract-toggle,
  .paper-btn {
    display: none;
  }

  .paper-abstract {
    display: block;
  }

  body {
    font-size: 12pt;
    background: white;
  }

  .paper-card {
    box-shadow: none;
    border: 1px solid #ccc;
    page-break-inside: avoid;
  }
}