/* ===== DESIGN TOKENS ===== */
:root {
  /* Type scale */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.5rem);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 5rem);

  /* Spacing (4px system) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Fonts */
  --font-display: 'Cabinet Grotesk', 'Inter', sans-serif;
  --font-body: 'Satoshi', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Content widths */
  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;
}

/* ===== LIGHT MODE ===== */
:root,
[data-theme='light'] {
  --color-bg: #f5f5f0;
  --color-surface: #fafaf7;
  --color-surface-2: #ffffff;
  --color-surface-offset: #eeeee9;
  --color-surface-dynamic: #e4e4df;
  --color-divider: #d6d6d0;
  --color-border: #c8c8c2;

  --color-text: #1a1a18;
  --color-text-muted: #6b6b65;
  --color-text-faint: #a3a39d;
  --color-text-inverse: #fafaf7;

  --color-primary: #0f6e5c;
  --color-primary-hover: #0a5647;
  --color-primary-active: #073d33;
  --color-primary-highlight: #d4ece6;

  --shadow-sm: 0 1px 2px oklch(0.2 0.01 80 / 0.06);
  --shadow-md: 0 4px 12px oklch(0.2 0.01 80 / 0.08);
  --shadow-lg: 0 12px 32px oklch(0.2 0.01 80 / 0.12);
}

/* ===== DARK MODE ===== */
[data-theme='dark'] {
  --color-bg: #111110;
  --color-surface: #1a1a18;
  --color-surface-2: #222220;
  --color-surface-offset: #1e1e1c;
  --color-surface-dynamic: #2a2a28;
  --color-divider: #2d2d2b;
  --color-border: #3a3a38;

  --color-text: #e0e0db;
  --color-text-muted: #8a8a84;
  --color-text-faint: #5a5a55;
  --color-text-inverse: #1a1a18;

  --color-primary: #3db89e;
  --color-primary-hover: #2da088;
  --color-primary-active: #1f8872;
  --color-primary-highlight: #1d332d;

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.2);
  --shadow-md: 0 4px 12px oklch(0 0 0 / 0.3);
  --shadow-lg: 0 12px 32px oklch(0 0 0 / 0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #111110;
    --color-surface: #1a1a18;
    --color-surface-2: #222220;
    --color-surface-offset: #1e1e1c;
    --color-surface-dynamic: #2a2a28;
    --color-divider: #2d2d2b;
    --color-border: #3a3a38;
    --color-text: #e0e0db;
    --color-text-muted: #8a8a84;
    --color-text-faint: #5a5a55;
    --color-text-inverse: #1a1a18;
    --color-primary: #3db89e;
    --color-primary-hover: #2da088;
    --color-primary-active: #1f8872;
    --color-primary-highlight: #1d332d;
    --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.2);
    --shadow-md: 0 4px 12px oklch(0 0 0 / 0.3);
    --shadow-lg: 0 12px 32px oklch(0 0 0 / 0.4);
  }
}

/* ===== HEADER ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: oklch(from var(--color-bg) l c h / 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid oklch(from var(--color-text) l c h / 0.06);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1),
              box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.header--hidden { transform: translateY(-100%); }
.header--scrolled { box-shadow: var(--shadow-sm); }

.header-inner {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding: var(--space-3) var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-text);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-sm);
  white-space: nowrap;
}

.nav ul {
  display: flex;
  gap: var(--space-6);
  list-style: none;
}

.nav a {
  text-decoration: none;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  position: relative;
  padding: var(--space-1) 0;
}

.nav a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.nav a:hover { color: var(--color-text); }
.nav a:hover::after { width: 100%; }

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.theme-toggle {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
}

.theme-toggle:hover { color: var(--color-text); background: var(--color-surface-offset); }

.mobile-menu-btn {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  color: var(--color-text);
}

@media (max-width: 768px) {
  .nav { 
    display: none; 
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-divider);
    padding: var(--space-4);
    box-shadow: var(--shadow-md);
  }
  .nav.active { display: block; }
  .nav ul { flex-direction: column; gap: var(--space-1); }
  .nav a { display: block; padding: var(--space-3) var(--space-4); border-radius: var(--radius-md); font-size: var(--text-base); }
  .nav a:hover { background: var(--color-surface-offset); }
  .nav a::after { display: none; }
  .mobile-menu-btn { display: flex; }
}

/* ===== HERO ===== */
.hero {
  padding: clamp(var(--space-16), 10vw, var(--space-32)) var(--space-4);
  min-height: 85vh;
  display: flex;
  align-items: center;
}

.hero-inner {
  max-width: var(--content-wide);
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: center;
  width: 100%;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 500;
  margin-bottom: var(--space-3);
}

.hero-title {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: var(--space-6);
  line-height: 1.05;
  letter-spacing: -0.025em;
}

.hero-description {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 52ch;
  margin-bottom: var(--space-8);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-10);
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  gap: var(--space-8);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-divider);
}

.stat { display: flex; flex-direction: column; }
.stat-number {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
}
.stat-suffix {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
}
.stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

/* Hero code block */
.hero-visual {
  display: flex;
  justify-content: center;
}

.hero-code-block {
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.08);
  border-radius: var(--radius-xl);
  overflow: hidden;
  width: 100%;
  max-width: 480px;
  box-shadow: var(--shadow-lg);
}

.code-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface-offset);
  border-bottom: 1px solid oklch(from var(--color-text) l c h / 0.06);
}

.code-dot {
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.code-filename {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-left: var(--space-2);
}

.hero-code-block pre {
  padding: var(--space-5);
  overflow-x: auto;
}

.hero-code-block code {
  font-family: var(--font-mono);
  font-size: clamp(0.75rem, 0.65rem + 0.5vw, 0.875rem);
  line-height: 1.7;
  color: var(--color-text-muted);
}

.code-keyword { color: var(--color-primary); font-weight: 500; }
.code-type { color: #d97706; }
.code-string { color: #16a34a; }

[data-theme='dark'] .code-type { color: #fbbf24; }
[data-theme='dark'] .code-string { color: #4ade80; }

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: var(--space-8); }
  .hero-visual { display: none; }
  .hero { min-height: auto; padding-top: var(--space-16); padding-bottom: var(--space-16); }
  .hero-title { font-size: var(--text-2xl); }
  .hero-stats { gap: var(--space-6); }
}

@media (max-width: 480px) {
  .hero-stats { flex-direction: column; gap: var(--space-4); }
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
}
.btn-primary:hover { background: var(--color-primary-hover); border-color: var(--color-primary-hover); }
.btn-primary:active { background: var(--color-primary-active); }

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn-secondary:hover { background: var(--color-surface-offset); border-color: var(--color-text-muted); }

/* ===== SECTIONS ===== */
.section {
  padding: clamp(var(--space-12), 8vw, var(--space-24)) var(--space-4);
}

.section-alt {
  background: var(--color-surface);
}

.container {
  max-width: var(--content-wide);
  margin-inline: auto;
}

.section-header {
  margin-bottom: var(--space-10);
}

.section-label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
  letter-spacing: 0.1em;
  display: block;
  margin-bottom: var(--space-2);
}

.section-title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
}

/* ===== ABOUT ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: start;
}

.about-text p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
  line-height: 1.7;
}

.about-text p:last-child { margin-bottom: 0; }

.about-highlights {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.highlight-card {
  padding: var(--space-5);
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.06);
  border-radius: var(--radius-lg);
  transition: box-shadow 0.3s ease, transform 0.3s ease;
}

.highlight-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.highlight-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.highlight-card h3 {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  margin-bottom: var(--space-2);
  color: var(--color-text);
}

.highlight-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
}

@media (max-width: 768px) {
  .about-grid { grid-template-columns: 1fr; gap: var(--space-8); }
}

/* ===== EXPERIENCE TIMELINE ===== */
.timeline {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.timeline-item {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: var(--space-8);
  padding: var(--space-6);
  border-radius: var(--radius-lg);
  transition: background 0.2s ease;
}

.timeline-item:hover {
  background: oklch(from var(--color-text) l c h / 0.03);
}

.timeline-date {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding-top: var(--space-1);
}

.date-range {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  white-space: nowrap;
}

.location {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

.timeline-content h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  margin-bottom: var(--space-1);
  color: var(--color-text);
}

.company {
  font-size: var(--text-sm);
  color: var(--color-primary);
  font-weight: 500;
  display: block;
  margin-bottom: var(--space-4);
}

.timeline-content ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.timeline-content li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-left: var(--space-5);
  position: relative;
  line-height: 1.6;
}

.timeline-content li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  opacity: 0.5;
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.tech-tags span {
  padding: var(--space-1) var(--space-3);
  background: var(--color-primary-highlight);
  color: var(--color-primary);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: var(--radius-full);
  white-space: nowrap;
}

[data-theme='dark'] .tech-tags span {
  background: var(--color-primary-highlight);
  color: var(--color-primary);
}

@media (max-width: 768px) {
  .timeline-item { grid-template-columns: 1fr; gap: var(--space-2); padding: var(--space-4); }
  .timeline-date { flex-direction: row; gap: var(--space-3); align-items: center; }
}

/* ===== EDUCATION ===== */
.education-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-8);
  padding: var(--space-8);
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.06);
  border-radius: var(--radius-xl);
}

.edu-main h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  margin-bottom: var(--space-2);
  color: var(--color-text);
}

.edu-main .company { margin-bottom: var(--space-1); }
.edu-main .date-range { display: block; margin-top: var(--space-1); }

.edu-gpa {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}

.gpa-value {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 800;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.gpa-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.edu-courses h4 {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-3);
}

@media (max-width: 768px) {
  .education-card { grid-template-columns: 1fr; gap: var(--space-6); padding: var(--space-5); }
}

/* ===== PROJECTS ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(340px, 100%), 1fr));
  gap: var(--space-5);
}

.project-card {
  padding: var(--space-6);
  background: var(--color-bg);
  border: 1px solid oklch(from var(--color-text) l c h / 0.06);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  transition: box-shadow 0.3s ease, transform 0.3s ease;
}

.project-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.project-featured {
  grid-column: 1 / -1;
  background: var(--color-bg);
}

@media (min-width: 769px) {
  .project-featured {
    display: grid;
    grid-template-columns: 1fr;
    padding: var(--space-8);
  }
}

.project-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.project-type {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
  font-weight: 500;
}

.project-top svg {
  color: var(--color-text-faint);
}

.project-card h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
}

.project-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
  flex: 1;
}

.project-date {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

/* ===== SKILLS ===== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(280px, 100%), 1fr));
  gap: var(--space-5);
}

.skill-group {
  padding: var(--space-5);
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.06);
  border-radius: var(--radius-lg);
}

.skill-group h3 {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  margin-bottom: var(--space-4);
  color: var(--color-text);
}

.skill-items {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.skill-items span {
  padding: var(--space-1) var(--space-3);
  background: var(--color-surface-offset);
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: var(--radius-full);
}

/* ===== CONTACT ===== */
.contact-inner {
  max-width: var(--content-narrow);
  text-align: left;
}

.contact-text {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  margin-bottom: var(--space-8);
  line-height: 1.7;
}

.contact-links {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
}

/* ===== FOOTER ===== */
.footer {
  padding: var(--space-8) var(--space-4);
  border-top: 1px solid var(--color-divider);
}

.footer .container {
  display: flex;
  justify-content: center;
}

.footer p {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

/* ===== SCROLL ANIMATIONS ===== */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}