/* Global CSS - Minimalist Portfolio */
:root {
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  --color-bg: #ffffff;
  --color-text: #1a1a1a;
  --color-accent: #666666;
  --color-border: #eaeaea;
  --spacing-unit: 1rem;
  --container-width: 680px;
}

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

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

body {
  padding: var(--spacing-unit);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease, opacity 0.2s ease;
}

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

img {
  max-width: 100%;
  height: auto;
  display: block;
  border: 1px solid var(--color-border);
}

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

h1 {
  font-size: 2.5rem;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.8rem;
  margin-top: calc(var(--spacing-unit) * 3);
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.4rem;
  margin-top: calc(var(--spacing-unit) * 2);
}

p {
  margin-bottom: var(--spacing-unit);
  color: #333;
}

ul {
  list-style: none;
  margin-bottom: var(--spacing-unit);
}

/* Layout */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: calc(var(--spacing-unit) * 2) 0;
}

/* Header & Nav */
header {
  margin-bottom: calc(var(--spacing-unit) * 4);
}

nav ul {
  display: flex;
  gap: calc(var(--spacing-unit) * 1.5);
}

nav a {
  font-weight: 500;
  color: var(--color-accent);
}

nav a:hover, nav a.active {
  color: var(--color-text);
}

/* Footer */
footer {
  margin-top: auto;
  padding-top: calc(var(--spacing-unit) * 4);
  border-top: 1px solid var(--color-border);
  color: var(--color-accent);
  font-size: 0.875rem;
  display: flex;
  justify-content: space-between;
}

/* Sections */
section {
  margin-bottom: calc(var(--spacing-unit) * 4);
}

.bio {
  font-size: 1.25rem;
  color: var(--color-text);
  margin-bottom: calc(var(--spacing-unit) * 2);
}

.skills-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skills-list li {
  background: #f5f5f5;
  padding: 0.25rem 0.75rem;
  border-radius: 4px;
  font-size: 0.875rem;
  color: #444;
}

/* Project List */
.project-list {
  display: grid;
  gap: calc(var(--spacing-unit) * 2);
}

.project-item {
  display: block;
  padding: calc(var(--spacing-unit) * 1.5);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.project-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
  border-color: #d0d0d0;
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.5rem;
}

.project-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 0;
}

.project-category {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-accent);
}

.project-desc {
  color: #555;
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
}

.project-meta {
  font-size: 0.85rem;
  color: var(--color-accent);
}

/* Project Detail */
.project-detail-header {
  margin-bottom: calc(var(--spacing-unit) * 2);
}

.project-detail-info {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-unit);
  margin-bottom: calc(var(--spacing-unit) * 2);
  padding: var(--spacing-unit);
  background: #f9f9f9;
  border-radius: 8px;
}

.info-item h4 {
  font-size: 0.8rem;
  color: var(--color-accent);
  text-transform: uppercase;
  margin-bottom: 0.25rem;
}

.info-item p {
  font-size: 1rem;
  margin: 0;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--color-text);
  color: var(--color-bg);
  border-radius: 6px;
  font-weight: 500;
  border: none;
}

.btn:hover {
  background: #000;
  opacity: 0.9;
  border-color: transparent;
  color: white;
}

/* Filter Nav */
.filter-nav {
  margin-bottom: calc(var(--spacing-unit) * 2);
  display: flex;
  gap: 1rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.5rem;
}

.filter-nav a {
  padding-bottom: 0.5rem;
  color: var(--color-accent);
  margin-bottom: -0.55rem; /* Overlap border */
  border-bottom: 2px solid transparent;
}

.filter-nav a:hover, .filter-nav a.active {
  color: var(--color-text);
  border-bottom-color: var(--color-text);
}

/* Mobile Responsive */
@media (max-width: 600px) {
  :root {
    --container-width: 100%;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  .filter-nav {
    overflow-x: auto;
    white-space: nowrap;
    padding-bottom: 0.75rem; /* Scroll space */
  }
}