/* ===========================
   DESIGN TOKENS
   =========================== */

:root,
[data-theme='light'] {
  /* Surfaces — cool off-white */
  --color-bg: #f4f5f7;
  --color-surface: #ffffff;
  --color-surface-2: #f9fafb;
  --color-surface-offset: #eef0f3;
  --color-divider: #e2e5ea;
  --color-border: #d5d8de;

  /* Text */
  --color-text: #111318;
  --color-text-muted: #5c6070;
  --color-text-faint: #9da3b0;
  --color-text-inverse: #f4f5f7;

  /* Accent — electric indigo */
  --color-primary: #4361ee;
  --color-primary-hover: #2f4ad6;
  --color-primary-active: #1e35b8;
  --color-primary-highlight: #dce2fc;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.625rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;

  /* Spacing */
  --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;

  /* 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);
  --text-hero: clamp(3rem,     0.5rem + 7vw,    8rem);

  /* Fonts */
  --font-display: 'Cabinet Grotesk', 'Helvetica Neue', sans-serif;
  --font-body: 'Satoshi', 'Inter', sans-serif;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(67,97,238,0.06);
  --shadow-md: 0 4px 16px rgba(67,97,238,0.10);
  --shadow-lg: 0 12px 40px rgba(67,97,238,0.14);

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

  /* Layout */
  --content-default: 1080px;
  --content-narrow: 680px;
}

[data-theme='dark'] {
  --color-bg: #0d0f14;
  --color-surface: #13161d;
  --color-surface-2: #181b23;
  --color-surface-offset: #1c1f28;
  --color-divider: #242835;
  --color-border: #2e3345;
  --color-text: #e8eaf0;
  --color-text-muted: #8890a6;
  --color-text-faint: #4a5168;
  --color-text-inverse: #0d0f14;
  --color-primary: #7b93f8;
  --color-primary-hover: #9baff9;
  --color-primary-active: #b8c7fb;
  --color-primary-highlight: #1c2245;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.25);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.35);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.5);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #0d0f14;
    --color-surface: #13161d;
    --color-surface-2: #181b23;
    --color-surface-offset: #1c1f28;
    --color-divider: #242835;
    --color-border: #2e3345;
    --color-text: #e8eaf0;
    --color-text-muted: #8890a6;
    --color-text-faint: #4a5168;
    --color-text-inverse: #0d0f14;
    --color-primary: #7b93f8;
    --color-primary-hover: #9baff9;
    --color-primary-active: #b8c7fb;
    --color-primary-highlight: #1c2245;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.25);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.35);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.5);
  }
}

/* ===========================
   RESET / BASE
   =========================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  scroll-padding-top: 72px;
}

body {
  min-height: 100dvh;
  line-height: 1.65;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color 0.3s, color 0.3s;
}

img, picture, svg { display: block; max-width: 100%; }
ul[role='list'], ol[role='list'] { list-style: none; }

h1, h2, h3, h4 {
  text-wrap: balance;
  line-height: 1.12;
  font-family: var(--font-display);
}

p, li { text-wrap: pretty; }

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

button { cursor: pointer; background: none; border: none; font: inherit; color: inherit; }

::selection { background: var(--color-primary-highlight); color: var(--color-text); }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: var(--radius-sm); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ===========================
   LAYOUT
   =========================== */

.container {
  width: min(var(--content-default), 100% - var(--space-8));
  margin-inline: auto;
}

.section {
  padding-block: clamp(var(--space-16), 8vw, var(--space-32));
}

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

/* ===========================
   NAV
   =========================== */

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--color-bg) 85%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-divider);
  transition: box-shadow var(--transition), background var(--transition);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-sm);
  letter-spacing: -0.01em;
  margin-right: auto;
}

.logo-text { color: var(--color-text); }

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  list-style: none;
}

.nav-links a {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
}

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

.btn-nav {
  background: var(--color-primary);
  color: var(--color-text-inverse) !important;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  font-size: var(--text-sm) !important;
  font-weight: 600 !important;
  transition: background var(--transition), transform var(--transition);
}

.btn-nav:hover {
  background: var(--color-primary-hover);
  transform: translateY(-1px);
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}

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

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 6px;
  border-radius: var(--radius-sm);
}

.nav-hamburger span {
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

@media (max-width: 720px) {
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }
}

/* ===========================
   HERO
   =========================== */

.hero {
  position: relative;
  min-height: 92vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-inner {
  position: relative;
  z-index: 2;
  padding-block: clamp(var(--space-16), 10vw, var(--space-32));
}

.hero-badge {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: var(--color-primary-highlight);
  border: 1px solid color-mix(in srgb, var(--color-primary) 25%, transparent);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-6);
}

.hero-name {
  font-size: var(--text-hero);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--color-text);
  line-height: 0.95;
  margin-bottom: var(--space-5);
}

.hero-surname {
  color: var(--color-primary);
}

.hero-tagline {
  font-size: var(--text-lg);
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: var(--space-5);
  font-family: var(--font-body);
}

.hero-bio {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 54ch;
  line-height: 1.7;
  margin-bottom: var(--space-8);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-primary);
  color: white;
  font-size: var(--text-sm);
  font-weight: 600;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-md);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: var(--text-sm);
  font-weight: 600;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  transition: background var(--transition), border-color var(--transition), transform var(--transition);
}

.btn-secondary:hover {
  background: var(--color-surface-offset);
  transform: translateY(-2px);
}

/* Grid background */
.hero-grid-bg {
  position: absolute;
  inset: 0;
  z-index: 1;
  background-image:
    linear-gradient(var(--color-divider) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-divider) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: 0.45;
  mask-image: radial-gradient(ellipse 80% 80% at 60% 40%, black 0%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 80% at 60% 40%, black 0%, transparent 75%);
}

/* ===========================
   SECTION LABELS & TITLES
   =========================== */

.section-label {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: var(--text-2xl);
  font-weight: 800;
  letter-spacing: -0.025em;
  color: var(--color-text);
  margin-bottom: var(--space-10);
}

/* ===========================
   ABOUT
   =========================== */

.about-layout {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-12);
  align-items: start;
}

.about-layout .section-label {
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  margin-bottom: 0;
  align-self: start;
  padding-top: var(--space-2);
}

.about-content p {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 64ch;
  margin-bottom: var(--space-5);
  line-height: 1.75;
}

.about-content p strong { color: var(--color-text); }

.about-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--space-4);
  margin-top: var(--space-10);
}

.stat {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  transition: box-shadow var(--transition), transform var(--transition);
}

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

.stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: var(--space-2);
}

.stat-label {
  display: block;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: 500;
}

@media (max-width: 640px) {
  .about-layout {
    grid-template-columns: 1fr;
  }
  .about-layout .section-label {
    writing-mode: horizontal-tb;
    transform: none;
  }
}

/* ===========================
   SKILLS
   =========================== */

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-5);
}

.skill-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}

.skill-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
  border-color: color-mix(in srgb, var(--color-primary) 30%, var(--color-border));
}

.skill-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-primary-highlight);
  border-radius: var(--radius-md);
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.skill-card h3 {
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--color-text);
  margin-bottom: var(--space-4);
  font-family: var(--font-display);
}

.skill-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.skill-list li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-left: var(--space-4);
  position: relative;
}

.skill-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--color-primary);
  opacity: 0.6;
}

/* ===========================
   EXPERIENCE / TIMELINE
   =========================== */

.timeline {
  display: flex;
  flex-direction: column;
  gap: 0;
  position: relative;
  padding-left: var(--space-8);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--color-divider);
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-12);
}

.timeline-item:last-child { padding-bottom: 0; }

.timeline-dot {
  position: absolute;
  left: calc(-1 * var(--space-8) + 1px);
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 3px solid var(--color-bg);
  box-shadow: 0 0 0 2px var(--color-primary);
}

.timeline-content {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: box-shadow var(--transition);
}

.timeline-content:hover { box-shadow: var(--shadow-md); }

.timeline-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  flex-wrap: wrap;
}

.timeline-date {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 500;
}

.timeline-tag {
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-primary);
  background: var(--color-primary-highlight);
  padding: 2px var(--space-3);
  border-radius: var(--radius-full);
}

.timeline-content h3 {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-1);
  letter-spacing: -0.01em;
}

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

.timeline-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: 0;
}

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

.timeline-bullets li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-size: 0.8em;
  top: 0.15em;
}

.timeline-bullets strong { color: var(--color-text); font-weight: 600; }

/* ===========================
   PROJECTS
   =========================== */

.projects-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: auto auto;
  gap: var(--space-5);
}

.project-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}

.project-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--color-primary) 35%, var(--color-border));
}

.project-card.featured {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-primary-highlight) 100%);
  border-color: color-mix(in srgb, var(--color-primary) 25%, var(--color-border));
}

.project-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  flex-wrap: wrap;
}

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

.tag {
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-primary);
  background: var(--color-primary-highlight);
  padding: 3px var(--space-3);
  border-radius: var(--radius-full);
}

.project-date {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 500;
  white-space: nowrap;
}

.project-card h3 {
  font-size: var(--text-xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--color-text);
}

.project-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.7;
  flex: 1;
}

.project-highlights {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.project-highlights li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-left: var(--space-5);
  position: relative;
  line-height: 1.5;
}

.project-highlights li::before {
  content: '✦';
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-size: 0.65em;
  top: 0.25em;
}

.project-highlights strong { color: var(--color-text); }

.project-stack {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 500;
  font-family: var(--font-display);
  letter-spacing: 0.02em;
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-divider);
  margin-top: auto;
}

@media (max-width: 640px) {
  .projects-grid { grid-template-columns: 1fr; }
  .project-card.featured { grid-column: 1; }
}

/* ===========================
   EDUCATION
   =========================== */

.edu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-5);
}

.edu-card {
  display: flex;
  align-items: flex-start;
  gap: var(--space-5);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: box-shadow var(--transition), transform var(--transition);
}

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

.edu-icon {
  flex-shrink: 0;
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-primary-highlight);
  border-radius: var(--radius-md);
}

.edu-info h3 {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-1);
  letter-spacing: -0.01em;
}

.edu-school {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
}

.edu-meta {
  display: flex;
  gap: var(--space-3);
  align-items: center;
  flex-wrap: wrap;
}

.edu-gpa {
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-primary);
  background: var(--color-primary-highlight);
  padding: 2px var(--space-3);
  border-radius: var(--radius-full);
}

.edu-year {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 500;
}

/* ===========================
   CONTACT
   =========================== */

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

.contact-inner {
  max-width: var(--content-narrow);
}

.contact-sub {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 50ch;
  margin-top: calc(-1 * var(--space-6));
  margin-bottom: var(--space-10);
}

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

.contact-link {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text-muted);
  padding: var(--space-4) var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
}

.contact-link svg {
  flex-shrink: 0;
  color: var(--color-primary);
}

.contact-link:hover {
  color: var(--color-text);
  border-color: color-mix(in srgb, var(--color-primary) 40%, var(--color-border));
  background: var(--color-surface-2);
  transform: translateX(4px);
  box-shadow: var(--shadow-sm);
}

/* ===========================
   FOOTER
   =========================== */

.footer {
  padding-block: var(--space-8);
  border-top: 1px solid var(--color-divider);
  background: var(--color-bg);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

/* ===========================
   SCROLL ANIMATIONS
   =========================== */

.fade-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1), transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}