/* =========================================================
   PORTFOLIO STYLESHEET
   Design tokens -> Base -> Layout -> Components -> Sections -> Responsive
   ========================================================= */

/* ---------- Design Tokens ---------- */
:root {
  /* Light theme */
  --bg: #F8FAFC;
  --bg-alt: #F1F5F9;
  --surface: #FFFFFF;
  --border: #E2E8F0;
  --text: #1E293B;
  --text-muted: #55637A;
  --accent: #4F46E5;      /* indigo */
  --accent-hover: #4338CA;
  --accent-teal: #0D9488; /* secondary accent */
  --shadow: 0 4px 20px rgba(15, 23, 42, 0.06);
  --shadow-hover: 0 12px 32px rgba(15, 23, 42, 0.10);

  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.25s ease;
  --nav-height: 72px;
}

[data-theme="dark"] {
  --bg: #0B1120;
  --bg-alt: #0F172A;
  --surface: #141B2D;
  --border: #253147;
  --text: #E2E8F0;
  --text-muted: #94A3B8;
  --accent: #818CF8;
  --accent-hover: #A5B4FC;
  --accent-teal: #2DD4BF;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
  --shadow-hover: 0 16px 36px rgba(0, 0, 0, 0.45);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background-color var(--transition), color var(--transition);
  overflow-x: hidden;
}

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

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }

.mono { font-family: var(--font-mono); }

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Visible keyboard focus for accessibility */
a:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 26px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform var(--transition), box-shadow var(--transition), background-color var(--transition), color var(--transition);
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background-color: var(--accent);
  color: #ffffff;
  box-shadow: var(--shadow);
}
.btn-primary:hover { background-color: var(--accent-hover); box-shadow: var(--shadow-hover); }

.btn-outline {
  background-color: transparent;
  color: var(--text);
  border: 1.5px solid var(--border);
}
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }

.btn-small { padding: 8px 16px; font-size: 0.85rem; }
.btn-large { padding: 16px 34px; font-size: 1rem; }

/* ---------- Navbar ---------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  z-index: 1000;
  background-color: rgba(248, 250, 252, 0.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), background-color var(--transition);
}
[data-theme="dark"] .navbar { background-color: rgba(11, 17, 32, 0.75); }
.navbar.scrolled { border-bottom-color: var(--border); }

.nav-container {
  width: 100%;
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}
.logo-bracket { color: var(--accent); }

.nav-links {
  display: flex;
  gap: 32px;
}
.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-muted);
  position: relative;
  transition: color var(--transition);
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0; bottom: -6px;
  width: 0%; height: 2px;
  background-color: var(--accent);
  transition: width var(--transition);
}
.nav-link:hover { color: var(--text); }
.nav-link:hover::after { width: 100%; }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.theme-toggle {
  width: 38px; height: 38px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  border: 1px solid var(--border);
  font-size: 0.95rem;
  transition: border-color var(--transition), transform 0.4s ease;
}
.theme-toggle:hover { border-color: var(--accent); transform: rotate(20deg); }

.nav-resume-link { display: inline-flex; }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 26px;
}
.hamburger span {
  height: 2px;
  width: 100%;
  background-color: var(--text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  overflow: hidden;
}

.hero-bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--border) 1px, transparent 1px),
    linear-gradient(to bottom, var(--border) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 30%, black 30%, transparent 75%);
  opacity: 0.6;
  pointer-events: none;
}

.hero-container {
  position: relative;
  z-index: 1;
  max-width: 780px;
}

.eyebrow {
  color: var(--accent-teal);
  font-size: 0.9rem;
  font-weight: 500;
  margin-bottom: 18px;
  opacity: 0;
  animation: fadeUp 0.6s ease forwards;
}

.hero-name {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.05;
  margin-bottom: 20px;
  opacity: 0;
  animation: fadeUp 0.6s ease 0.1s forwards;
}

.hero-tagline {
  font-size: clamp(1rem, 2.4vw, 1.25rem);
  color: var(--accent);
  margin-bottom: 24px;
  min-height: 1.6em;
  opacity: 0;
  animation: fadeUp 0.6s ease 0.2s forwards;
}
.prompt-symbol { color: var(--text-muted); margin-right: 10px; }
.cursor {
  display: inline-block;
  width: 2px;
  background-color: var(--accent);
  animation: blink 0.9s steps(1) infinite;
  margin-left: 2px;
}

.hero-subtext {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 560px;
  margin-bottom: 34px;
  opacity: 0;
  animation: fadeUp 0.6s ease 0.3s forwards;
}

.hero-actions {
  display: flex;
  gap: 16px;
  margin-bottom: 40px;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeUp 0.6s ease 0.4s forwards;
}

.hero-socials {
  display: flex;
  gap: 20px;
  font-size: 1.3rem;
  color: var(--text-muted);
  opacity: 0;
  animation: fadeUp 0.6s ease 0.5s forwards;
}
.hero-socials a { transition: color var(--transition), transform var(--transition); }
.hero-socials a:hover { color: var(--accent); transform: translateY(-3px); }

.scroll-indicator {
  position: absolute;
  bottom: 34px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--text-muted);
  font-size: 1.1rem;
  animation: bounce 2s ease-in-out infinite;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes blink {
  50% { opacity: 0; }
}
@keyframes bounce {
  0%, 100% { transform: translate(-50%, 0); }
  50% { transform: translate(-50%, 8px); }
}

/* ---------- Section Shared ---------- */
.section {
  padding: 110px 0;
}
.section-alt { background-color: var(--bg-alt); }

.section-label {
  color: var(--accent-teal);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 10px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-subtitle {
  color: var(--text-muted);
  max-width: 560px;
  margin-bottom: 48px;
}

/* Scroll reveal (JS toggles .is-visible) */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text p { color: var(--text-muted); margin-bottom: 18px; }

.about-stats {
  display: flex;
  gap: 36px;
  margin-top: 28px;
}
.stat { display: flex; flex-direction: column; }
.stat-number { font-size: 1.7rem; font-weight: 700; color: var(--accent); }
.stat-label { font-size: 0.85rem; color: var(--text-muted); }

.about-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
}
.about-info-list li {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}
.about-info-list li:last-child { border-bottom: none; }
.about-info-list i { color: var(--accent); width: 18px; }

/* ---------- Skills ---------- */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.skill-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform var(--transition), box-shadow var(--transition);
}
.skill-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }

.skill-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}
.skill-card-header i { color: var(--accent); font-size: 1.2rem; }
.skill-card-header h3 { font-size: 1.05rem; font-weight: 600; }

.chip-list { display: flex; flex-wrap: wrap; gap: 10px; }
.chip {
  font-size: 0.82rem;
  padding: 6px 12px;
  border-radius: 20px;
  background-color: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--text-muted);
  transition: border-color var(--transition), color var(--transition);
}
[data-theme="dark"] .chip { background-color: var(--bg); }
.chip-small { padding: 4px 10px; font-size: 0.75rem; }
.skill-card:hover .chip { border-color: var(--accent-teal); color: var(--text); }

/* ---------- Projects ---------- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.project-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition), box-shadow var(--transition);
}
.project-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }

.project-card-featured {
  grid-column: span 3;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 32px;
  padding: 36px;
}
.project-card-top {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  grid-column: 1 / -1;
}
.project-star { color: #F59E0B; }
.project-tag {
  font-size: 0.75rem;
  color: var(--accent-teal);
  border: 1px solid var(--accent-teal);
  padding: 3px 10px;
  border-radius: 20px;
}
.project-title { font-family: var(--font-display); font-size: 1.3rem; font-weight: 600; margin-bottom: 10px; }
.project-desc { color: var(--text-muted); font-size: 0.94rem; margin-bottom: 16px; }
.project-tech { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }

.project-features { margin-bottom: 20px; }
.project-features li {
  position: relative;
  padding-left: 20px;
  color: var(--text-muted);
  font-size: 0.92rem;
  margin-bottom: 6px;
}
.project-features li::before {
  content: "▸";
  position: absolute;
  left: 0;
  color: var(--accent);
}

.project-screenshot-placeholder {
  border: 1.5px dashed var(--border);
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 180px;
  color: var(--text-muted);
  font-size: 0.85rem;
  background-color: var(--bg-alt);
}
.project-screenshot-placeholder i { font-size: 1.8rem; opacity: 0.5; }

.project-links { display: flex; gap: 12px; margin-top: auto; }

/* Placeholder "add project" cards */
.project-card-placeholder {
  align-items: center;
  justify-content: center;
  text-align: center;
  border-style: dashed;
  color: var(--text-muted);
  gap: 12px;
}
.placeholder-icon {
  width: 48px; height: 48px;
  border-radius: 50%;
  border: 1.5px dashed var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem;
  color: var(--accent);
}
.project-title-placeholder { font-weight: 600; font-size: 1.05rem; }
.project-card-placeholder .project-desc { font-size: 0.88rem; }
.project-card-placeholder code {
  background-color: var(--bg-alt);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.85em;
}

/* ---------- Resume ---------- */
.resume-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.resume-section .section-title { margin-bottom: 8px; }
.resume-section .section-subtitle { margin-bottom: 0; }

/* ---------- Education Timeline ---------- */
.timeline {
  position: relative;
  padding-left: 32px;
  border-left: 2px solid var(--border);
}
.timeline-item {
  position: relative;
  padding-bottom: 40px;
}
.timeline-item:last-child { padding-bottom: 0; }
.timeline-dot {
  position: absolute;
  left: -38px;
  top: 4px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background-color: var(--accent);
  border: 3px solid var(--bg);
  box-shadow: 0 0 0 2px var(--accent);
}
.timeline-date {
  color: var(--accent-teal);
  font-size: 0.82rem;
  display: inline-block;
  margin-bottom: 8px;
}
.timeline-content h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 6px; }
.timeline-content p { color: var(--text-muted); font-size: 0.94rem; }

/* ---------- Certifications ---------- */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.cert-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
  transition: transform var(--transition), box-shadow var(--transition);
}
.cert-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
.cert-card i { font-size: 1.8rem; color: var(--accent); margin-bottom: 14px; }
.cert-card h3 { font-size: 1.02rem; font-weight: 600; margin-bottom: 6px; }
.cert-card p { color: var(--text-muted); font-size: 0.88rem; margin-bottom: 14px; }
.cert-link {
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: gap var(--transition);
}
.cert-link:hover { gap: 10px; }

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.contact-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 8px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}
.contact-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: var(--accent);
}
.contact-card i { font-size: 1.5rem; color: var(--accent); margin-bottom: 6px; }
.contact-label { font-size: 0.8rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; }
.contact-value { font-size: 0.92rem; font-weight: 500; word-break: break-word; }

/* ---------- Footer ---------- */
.footer {
  padding: 32px 0;
  border-top: 1px solid var(--border);
}
.footer-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--text-muted);
  font-size: 0.88rem;
}
.back-to-top {
  width: 38px; height: 38px;
  border-radius: 50%;
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  transition: border-color var(--transition), transform var(--transition);
}
.back-to-top:hover { border-color: var(--accent); transform: translateY(-3px); }

/* =========================================================
   RESPONSIVE
   ========================================================= */
@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: repeat(2, 1fr); }
  .projects-grid { grid-template-columns: repeat(2, 1fr); }
  .project-card-featured { grid-column: span 2; grid-template-columns: 1fr; }
  .cert-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 720px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0; right: 0;
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 20px 24px;
    gap: 18px;
    transform: translateY(-130%);
    opacity: 0;
    transition: transform var(--transition), opacity var(--transition);
  }
  .nav-links.open { transform: translateY(0); opacity: 1; }
  .nav-resume-link { display: none; }
  .hamburger { display: flex; }

  .skills-grid { grid-template-columns: 1fr; }
  .projects-grid { grid-template-columns: 1fr; }
  .project-card-featured { grid-column: span 1; }
  .cert-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }

  .resume-container { flex-direction: column; align-items: flex-start; }

  .section { padding: 80px 0; }
}

@media (max-width: 420px) {
  .contact-grid { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .about-stats { gap: 22px; }
}