/* ===================================
   1. CSS RESET & BASE STYLES
   =================================== */

html,
body {
  padding: 0;
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, Segoe UI, Roboto,
    Oxygen, Ubuntu, Cantarell, Fira Sans, Droid Sans, Helvetica Neue, sans-serif;
  overflow-x: hidden;
}

* {
  box-sizing: border-box;
}

a {
  color: inherit;
  text-decoration: none;
}

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

h1,
h2,
h3,
h5,
p,
ul {
  margin: 0;
}

ul {
  padding: 0;
  list-style: none;
}

button {
  padding: 0.5rem 1rem;
  font-weight: bold;
}

html {
  scroll-behavior: smooth;
}

/* ===================================
   2. DESIGN TOKENS (CSS VARIABLES)
   =================================== */

:root {
  /* Colors - Light Mode */
  --color-primary: #0070f3;
  --color-text: #000000;
  --color-text-secondary: #555555;
  --color-bg: #ffffff;
  --color-bg-secondary: #f1f1f1;
  --color-border: #eaeaea;
  --color-card-bg: #ffffff;
  --color-card-border: #e5e7eb;
  --color-hover-bg: #f5f5f5;
  --color-link-hover: #cccccc;
  
  /* Spacing Scale (base-8) */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  
  /* Typography Scale */
  --font-xs: 0.8rem;
  --font-sm: 0.9rem;
  --font-base: 1rem;
  --font-lg: 1.25rem;
  --font-xl: 1.5rem;
  --font-2xl: 1.953rem;
  --font-3xl: 2.441rem;
  --font-4xl: 3.052rem;
  
  /* Line Heights */
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Border Radius */
  --radius-sm: 3px;
  --radius-md: 6px;
  --radius-lg: 10px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s ease-out;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.15);
  
  /* Z-index */
  --z-nav: 100;
  --z-skip-link: 200;
}

/* ===================================
   3. TYPOGRAPHY SYSTEM
   =================================== */

body {
  font-size: var(--font-base);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
}

.title {
  margin: 0 0 var(--spacing-sm);
  line-height: var(--line-height-tight);
  font-size: var(--font-4xl);
  padding: 0 var(--spacing-sm);
  text-align: center;
}

.description {
  margin-top: var(--spacing-md);
  line-height: var(--line-height-normal);
  font-size: var(--font-xl);
  padding: 0 var(--spacing-sm);
  text-align: center;
}

.card h3 {
  margin: 0;
  padding: var(--spacing-md) var(--spacing-md) var(--spacing-xs);
  font-size: var(--font-xl);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  font-weight: 600;
}

.card p {
  margin: 0;
  font-size: var(--font-sm);
  line-height: var(--line-height-normal);
  padding: 0 var(--spacing-md) var(--spacing-md);
  color: var(--color-text-secondary);
  flex-grow: 1;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
}

/* ===================================
   4. LAYOUT COMPONENTS
   =================================== */

.container {
  min-height: 100vh;
  padding: 0 0.5rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

/* ===================================
   5. NAVIGATION
   =================================== */

#nav {
  position: sticky;
  z-index: var(--z-nav);
  top: 0;
  left: 0;
  right: 0;
  height: 80px;
  background-color: var(--color-bg);
  border-bottom: 2px solid var(--color-border);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 0 var(--spacing-md);
  transition: transform var(--transition-fast);
  margin-bottom: var(--spacing-md);
}

#textrow {
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  gap: var(--spacing-sm);
  text-decoration: none;
}

#title_nav {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  font-size: var(--font-base);
  font-weight: 500;
  text-decoration: none;
  transition: all var(--transition-fast);
  margin: var(--spacing-xs) var(--spacing-sm);
  position: relative;
  padding: var(--spacing-xs);
  min-height: 44px;
  min-width: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
}

#title_nav::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition-base), left var(--transition-base);
}

#title_nav:hover {
  color: var(--color-primary);
}

#title_nav:hover::after {
  width: 100%;
  left: 0;
}

#a_nav {
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  text-decoration: none;
  color: var(--color-text);
}

.svg_icon {
  display: inline-flex;
  margin-left: 4px;
}

/* ===================================
   6. COMPONENTS
   =================================== */

/* Profile Picture */
.pfp {
  display: flex;
  border-radius: 50%;
  width: 200px;
  height: 200px;
  margin: 0 auto;
  object-fit: cover;
  transition: transform var(--transition-base);
}

.pfp:hover {
  transform: scale(1.05) rotate(2deg);
}

/* Social Links Row */
.links_row {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  gap: var(--spacing-sm);
  text-decoration: none;
}

.link_card {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  min-width: 44px;
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--color-bg-secondary);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  font-weight: 500;
  justify-content: space-between;
  gap: var(--spacing-xs);
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
}

.link_card:hover {
  cursor: pointer;
  background-color: var(--color-link-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Project Cards */
.grid {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  max-width: 800px;
  margin-top: var(--spacing-lg);
}

#grid {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  padding: var(--spacing-sm);
  gap: var(--spacing-md);
}

.card {
  background-color: var(--color-card-bg);
  display: flex;
  flex-direction: column;
  border-radius: var(--radius-lg);
  border-width: 1px;
  border-style: solid;
  border-color: var(--color-card-border);
  align-items: stretch;
  text-decoration: none;
  width: 350px;
  height: 350px;
  margin: var(--spacing-sm);
  padding: 0;
  text-align: left;
  color: inherit;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  overflow: hidden;
}

.card:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--color-hover-bg);
  cursor: pointer;
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.img_container {
  width: 100%;
  height: 60%;
  overflow: hidden;
  border-radius: 0 0 var(--radius-lg) var(--radius-lg);
  flex-shrink: 0;
  order: 2;
}

.img {
  object-fit: cover;
  object-position: center;
  width: 100%;
  height: 100%;
  transition: opacity var(--transition-base);
}

.img:hover {
  opacity: 0.8;
  cursor: pointer;
}

/* About Page */
#main_about {
  padding: var(--spacing-2xl) 0;
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

#container_about {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: var(--spacing-sm);
}

#description_about {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  max-width: 600px;
}

.contact {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
}

#mail_about {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  color: var(--color-text);
  justify-content: space-between;
  gap: var(--spacing-xs);
  min-height: 44px;
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: #d3d3d3;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  text-decoration: none;
  transition: all var(--transition-base);
}

#mail_about:hover {
  cursor: pointer;
  background-color: #858585;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

#main_title_about {
  text-align: center;
  color: var(--color-text);
}

#main_projects {
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  padding-top: var(--spacing-md);
}

/* ===================================
   7. ANIMATIONS
   =================================== */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fade-in {
  animation: fadeInUp 0.8s ease-out forwards;
  opacity: 0;
  animation-fill-mode: forwards;
}

.animate-delay-1 { animation-delay: 0.1s; }
.animate-delay-2 { animation-delay: 0.2s; }
.animate-delay-3 { animation-delay: 0.3s; }
.animate-delay-4 { animation-delay: 0.4s; }
.animate-delay-5 { animation-delay: 0.5s; }
.animate-delay-6 { animation-delay: 0.6s; }
.animate-delay-7 { animation-delay: 0.7s; }

/* ===================================
   8. ACCESSIBILITY
   =================================== */

/* Focus states */
*:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

*:focus:not(:focus-visible) {
  outline: none;
}

/* Skip to content link */
.skip-to-content {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: var(--spacing-xs) var(--spacing-sm);
  text-decoration: none;
  z-index: var(--z-skip-link);
  border-radius: var(--radius-sm);
}

.skip-to-content:focus {
  top: var(--spacing-xs);
  left: var(--spacing-xs);
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}

/* ===================================
   9. RESPONSIVE DESIGN
   =================================== */

/* Tablets and below (max-width: 768px) */
@media (max-width: 768px) {
  #nav {
    height: auto;
    padding: var(--spacing-sm);
  }

  #textrow {
    flex-wrap: wrap;
    gap: var(--spacing-xs);
  }

  #title_nav {
    font-size: var(--font-sm);
    margin: var(--spacing-xs);
  }

  .title {
    font-size: var(--font-3xl);
    line-height: var(--line-height-tight);
  }

  .description {
    font-size: var(--font-xl);
    line-height: var(--line-height-normal);
  }

  .pfp {
    width: 150px;
    height: 150px;
  }

  .links_row {
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: 0 var(--spacing-sm);
  }

  .link_card {
    width: 100%;
    max-width: 300px;
    justify-content: center;
  }

  .grid {
    width: 100%;
    flex-direction: column;
  }

  .card {
    width: 90%;
    max-width: 350px;
    height: auto;
    min-height: 350px;
  }
  
  .img_container {
    height: 180px;
  }

  #description_about,
  .contact {
    width: 90%;
    max-width: 500px;
  }
}

/* Mobile devices (max-width: 480px) */
@media (max-width: 480px) {
  .title {
    font-size: var(--font-3xl);
  }

  .description {
    font-size: var(--font-base);
  }

  .pfp {
    width: 120px;
    height: 120px;
  }

  #title_nav {
    font-size: var(--font-xs);
    margin: 4px var(--spacing-xs);
  }
  
  .card {
    width: 95%;
    max-width: 300px;
    min-height: 320px;
  }
  
  .img_container {
    height: 150px;
  }
  
  .card h3 {
    font-size: var(--font-xl);
  }
  
  .card p {
    font-size: var(--font-base);
  }
}

/* ===================================
   10. DARK MODE
   =================================== */

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1a1a1a;
    --color-text: #ffffff;
    --color-text-secondary: #a0a0a0;
    --color-bg-secondary: #2a2a2a;
    --color-card-bg: #2a2a2a;
    --color-card-border: #3a3a3a;
    --color-border: #3a3a3a;
    --color-hover-bg: #333333;
    --color-link-hover: #424242;
  }
  
  body {
    background-color: var(--color-bg);
    color: var(--color-text);
  }
  
  #nav {
    background-color: var(--color-bg);
    border-bottom-color: var(--color-border);
  }
  
  .link_card {
    background-color: #0e0e0e;
  }
  
  .link_card:hover {
    background-color: var(--color-link-hover);
    box-shadow: 0 4px 6px rgba(255, 255, 255, 0.1);
  }
  
  .card {
    background-color: var(--color-card-bg);
    border-color: var(--color-card-border);
  }
  
  .card:hover {
    background-color: var(--color-hover-bg);
  }
  
  .img_container img {
    filter: brightness(0.9) contrast(1.1);
  }
  
  #description_about,
  .contact {
    background-color: var(--color-bg-secondary);
  }
  
  #mail_about {
    background-color: #3a3a3a;
    color: var(--color-text);
  }
  
  #mail_about:hover {
    background-color: #4a4a4a;
  }
}