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

:root {
  --color-bg: #0a0a0a;
  --color-text: #ffffff;
  --color-text-muted: #999999;
  --color-border: #2a2a2a;
  --color-accent: #ffffff;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
    sans-serif;
  --font-mono: "SF Mono", "Monaco", "Inconsolata", "Fira Code", "Fira Mono",
    "Roboto Mono", monospace;
  --spacing-unit: 8px;
  --max-width: 1200px;
}

/* Light mode */
:root[data-theme="light"] {
  --color-bg: #ffffff;
  --color-text: #1a1a1a;
  --color-text-muted: #666666;
  --color-border: #e5e5e5;
  --color-accent: #000000;
}

html {
  scroll-behavior: smooth;
  scrollbar-width: none; /* Firefox */
  -ms-overflow-style: none; /* IE and Edge */
}

html::-webkit-scrollbar {
  display: none; /* Chrome, Safari, Opera */
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Text Selection */
::selection {
  background-color: #ffffff;
  color: #0a0a0a;
}

::-moz-selection {
  background-color: #ffffff;
  color: #0a0a0a;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
  line-height: 1.2;
  font-weight: 600;
  margin-bottom: calc(var(--spacing-unit) * 2);
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.5rem, 3vw, 2.5rem);
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

p {
  margin-bottom: calc(var(--spacing-unit) * 2);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  border-bottom: 1px solid var(--color-border);
  transition: border-color 0.2s ease;
}

a:hover {
  border-bottom-color: var(--color-accent);
}

/* Layout */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 calc(var(--spacing-unit) * 3);
}

section {
  padding: calc(var(--spacing-unit) * 12) 0;
  border-bottom: 1px solid var(--color-border);
}

section:last-of-type {
  border-bottom: none;
}

/* Navigation */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background-color: rgba(10, 10, 10, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  padding: calc(var(--spacing-unit) * 2) 0;
}

:root[data-theme="light"] nav {
  background-color: rgba(255, 255, 255, 0.95);
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav a {
  border: none;
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  border-bottom: none;
  padding-top: calc(var(--spacing-unit) * 8);
}

.hero-content {
  max-width: 800px;
}

.hero h1 {
  margin-bottom: calc(var(--spacing-unit) * 3);
}

.hero .subtitle {
  font-size: clamp(1.1rem, 2vw, 1.5rem);
  color: var(--color-text-muted);
  margin-bottom: calc(var(--spacing-unit) * 4);
  line-height: 1.5;
}

.hero .description {
  font-size: 1.1rem;
  line-height: 1.7;
  margin-bottom: calc(var(--spacing-unit) * 4);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: calc(var(--spacing-unit) * 1.5) calc(var(--spacing-unit) * 3);
  background-color: var(--color-accent);
  color: var(--color-bg);
  border: 2px solid var(--color-accent);
  border-radius: 0;
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn:hover {
  background-color: var(--color-bg);
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

.btn-outline {
  background-color: transparent;
  color: var(--color-accent);
}

.btn-outline:hover {
  background-color: var(--color-accent);
  color: var(--color-bg);
}

/* Section Headers */
.section-header {
  margin-bottom: calc(var(--spacing-unit) * 6);
}

.section-title {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  margin-bottom: calc(var(--spacing-unit) * 2);
}

.section-description {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  max-width: 700px;
}

/* Projects Grid */
.projects-filter {
  display: flex;
  gap: calc(var(--spacing-unit) * 2);
  margin-bottom: calc(var(--spacing-unit) * 6);
  flex-wrap: wrap;
}

.filter-btn {
  padding: calc(var(--spacing-unit) * 1) calc(var(--spacing-unit) * 2);
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: var(--font-sans);
}

.filter-btn:hover,
.filter-btn.active {
  border-color: var(--color-accent);
  background-color: var(--color-accent);
  color: var(--color-bg);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: calc(var(--spacing-unit) * 4);
}

.project-card {
  border: 1px solid var(--color-border);
  padding: calc(var(--spacing-unit) * 4);
  transition: border-color 0.2s ease;
}

.project-card:hover {
  border-color: var(--color-accent);
}

.project-category {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: calc(var(--spacing-unit) * 1);
  font-weight: 600;
}

.project-card h3 {
  margin-bottom: calc(var(--spacing-unit) * 2);
  font-size: 1.4rem;
}

.project-card p {
  color: var(--color-text-muted);
  margin-bottom: calc(var(--spacing-unit) * 3);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--spacing-unit) * 1);
  margin-bottom: calc(var(--spacing-unit) * 3);
}

.tag {
  font-size: 0.75rem;
  padding: calc(var(--spacing-unit) * 0.5) calc(var(--spacing-unit) * 1);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
}

.project-link {
  font-size: 0.9rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Blog */
.blog-list {
  display: flex;
  flex-direction: column;
  gap: calc(var(--spacing-unit) * 4);
}

.blog-item {
  border-bottom: 1px solid var(--color-border);
  padding-bottom: calc(var(--spacing-unit) * 4);
}

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

.blog-date {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  margin-bottom: calc(var(--spacing-unit) * 1);
}

.blog-item h3 {
  font-size: 1.5rem;
  margin-bottom: calc(var(--spacing-unit) * 1);
}

.blog-item p {
  color: var(--color-text-muted);
}

/* Footer */
footer {
  padding: calc(var(--spacing-unit) * 8) 0;
  border-top: 1px solid var(--color-border);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: calc(var(--spacing-unit) * 3);
}

.social-links {
  display: flex;
  gap: calc(var(--spacing-unit) * 3);
  list-style: none;
}

.social-links a {
  border: none;
  font-size: 0.9rem;
  font-weight: 500;
}

/* Responsive */
@media (max-width: 768px) {
  nav ul {
    gap: calc(var(--spacing-unit) * 2);
  }

  nav a {
    font-size: 0.8rem;
  }

  .projects-grid {
    grid-template-columns: 1fr;
  }

  .footer-content {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* Utilities */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}