/* ============================================
   Sunny Shah — Portfolio Design System
   ============================================ */

:root {
  /* Colors */
  --bg-primary: #0c0f14;
  --bg-secondary: #141922;
  --bg-card: #1a1f2e;
  --bg-card-hover: #1f2638;
  --border: #2a3142;
  --border-focus: #4f7cff;
  --text-primary: #f0f2f5;
  --text-secondary: #a8b2c1;
  --text-muted: #6b7689;
  --accent: #4f7cff;
  --accent-hover: #6b91ff;
  --accent-muted: #3d5fcc;
  --success: #34c759;
  --tag-bg: #252b3b;
  --tag-border: #2a3142;

  /* Typography */
  --font-sans: "DM Sans", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --section-padding: clamp(3rem, 8vw, 5rem);
  --container-max: 720px;
  --container-wide: 960px;

  /* Layout */
  --nav-height: 64px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-full: 9999px;

  /* Motion */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --duration-fast: 150ms;
  --duration-normal: 250ms;
  --duration-slow: 400ms;
}

@media (prefers-reduced-motion: reduce) {
  :root {
    --duration-fast: 0ms;
    --duration-normal: 0ms;
    --duration-slow: 0ms;
  }
}

/* ============================================
   Reset & Base
   ============================================ */

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

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

a:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

ul {
  margin: 0 0 var(--space-md);
  padding-left: 1.25rem;
}

li {
  margin-bottom: var(--space-xs);
}

/* ============================================
   Skip link (accessibility)
   ============================================ */

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  z-index: 100;
  padding: var(--space-sm) var(--space-md);
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius-sm);
  font-weight: 600;
  transition: top var(--duration-normal) var(--ease-out);
}

.skip-link:focus {
  top: var(--space-md);
  outline: 2px solid #fff;
  outline-offset: 2px;
}

/* ============================================
   Header & Nav
   ============================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(12, 15, 20, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--duration-normal), box-shadow var(--duration-normal);
}

.site-header.scrolled {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.25);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-wide);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  height: var(--nav-height);
}

.nav-logo {
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--text-primary);
}

.nav-logo:hover {
  color: var(--accent);
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  color: var(--text-primary);
  transition: background var(--duration-fast), border-color var(--duration-fast);
}

.nav-toggle:hover,
.nav-toggle[aria-expanded="true"] {
  background: var(--bg-card);
  border-color: var(--border);
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  margin: 0 auto;
  background: currentColor;
  border-radius: 1px;
  transition: transform var(--duration-normal) var(--ease-out), opacity var(--duration-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(3.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-3.5px) rotate(-45deg);
}

.nav-menu {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--space-sm);
}

.nav-menu.open {
  display: flex;
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }

  .nav-menu {
    display: flex;
    flex-direction: row;
    align-items: center;
  }
}

.nav-menu a {
  display: block;
  padding: var(--space-sm) var(--space-md);
  color: var(--text-secondary);
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
}

.nav-menu a:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-cta {
  background: var(--accent) !important;
  color: #fff !important;
}

.nav-cta:hover {
  background: var(--accent-hover) !important;
  color: #fff !important;
}

@media (max-width: 767px) {
  .nav-menu {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    padding: var(--space-md);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
  }

  .nav-menu.open {
    display: flex;
  }

  .nav-menu a {
    padding: var(--space-md);
  }
}

/* ============================================
   Container
   ============================================ */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.projects .container {
  max-width: var(--container-wide);
}

/* ============================================
   Sections
   ============================================ */

.section {
  padding: var(--section-padding) 0;
}

.section-title {
  margin: 0 0 var(--space-xl);
  font-size: clamp(1.5rem, 4vw, 1.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

/* ============================================
   Hero
   ============================================ */

.hero {
  min-height: calc(100vh - var(--nav-height));
  display: flex;
  align-items: center;
  padding: var(--space-3xl) var(--space-lg);
  background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 50%, var(--bg-primary) 100%);
}

.hero-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  text-align: center;
}

.hero-label {
  margin: 0 0 var(--space-sm);
  font-size: 0.875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
}

.hero h1 {
  margin: 0 0 var(--space-md);
  font-size: clamp(2.25rem, 6vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--text-primary);
}

.hero-headline {
  margin: 0 0 var(--space-sm);
  font-size: clamp(1.0625rem, 2.5vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 42ch;
  margin-left: auto;
  margin-right: auto;
}

.hero-value {
  margin: 0 0 var(--space-lg);
  font-size: 1rem;
  color: var(--accent);
  font-weight: 500;
}

.hero-meta,
.hero-target {
  margin: 0 0 var(--space-sm);
  font-size: 0.9375rem;
  color: var(--text-muted);
  max-width: 52ch;
  margin-left: auto;
  margin-right: auto;
}

.hero-target {
  margin-bottom: var(--space-xl);
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.tag {
  display: inline-block;
  padding: var(--space-xs) var(--space-md);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--tag-bg);
  border: 1px solid var(--tag-border);
  border-radius: var(--radius-full);
  transition: background var(--duration-fast), border-color var(--duration-fast);
}

.tag:hover {
  background: var(--bg-card);
  border-color: var(--border);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-md);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-md) var(--space-xl);
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: background var(--duration-fast), color var(--duration-fast), transform var(--duration-fast);
}

.btn:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--text-muted);
}

@media (prefers-reduced-motion: no-preference) {
  .hero-label {
    animation: fadeInUp var(--duration-slow) var(--ease-out) both;
  }

  .hero h1 {
    animation: fadeInUp var(--duration-slow) var(--ease-out) 0.05s both;
  }

  .hero-headline {
    animation: fadeInUp var(--duration-slow) var(--ease-out) 0.1s both;
  }

  .hero-value {
    animation: fadeInUp var(--duration-slow) var(--ease-out) 0.15s both;
  }

  .hero-tags {
    animation: fadeInUp var(--duration-slow) var(--ease-out) 0.2s both;
  }

  .hero-cta {
    animation: fadeInUp var(--duration-slow) var(--ease-out) 0.25s both;
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   Cards (shared)
   ============================================ */

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: background var(--duration-fast), border-color var(--duration-fast), box-shadow var(--duration-fast);
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.card h3 {
  margin: 0 0 var(--space-md);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.card p {
  margin: 0 0 var(--space-md);
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
}

.card ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

/* ============================================
   About
   ============================================ */

.about-card .about-lead {
  margin-bottom: var(--space-lg);
}

.about-list {
  margin: 0;
  padding-left: 1.25rem;
}

.about-list li {
  margin-bottom: var(--space-sm);
}

/* ============================================
   Experience
   ============================================ */

.exp-card {
  margin-bottom: var(--space-lg);
}

.exp-card:last-child {
  margin-bottom: 0;
}

.exp-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-bottom: var(--space-xs);
}

.exp-header h3 {
  margin: 0;
  font-size: 1.0625rem;
}

.exp-date {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--accent);
  font-family: var(--font-mono);
}

.exp-role {
  margin: 0 0 var(--space-md) !important;
  font-size: 0.875rem;
  color: var(--text-muted) !important;
}

.exp-list {
  margin: 0;
  padding-left: 1.25rem;
}

.exp-list li {
  margin-bottom: var(--space-sm);
}

/* ============================================
   Projects
   ============================================ */

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

@media (min-width: 640px) {
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.project-card h3 {
  font-size: 1rem;
  margin-bottom: var(--space-sm);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-md);
}

.project-tag {
  display: inline-block;
  padding: 2px 8px;
  font-size: 0.75rem;
  font-weight: 500;
  font-family: var(--font-mono);
  color: var(--text-muted);
  background: var(--tag-bg);
  border: 1px solid var(--tag-border);
  border-radius: var(--radius-sm);
}

.project-desc {
  margin-bottom: var(--space-md) !important;
  font-size: 0.875rem !important;
}

.project-impact {
  margin: 0 0 var(--space-md);
  padding-left: 1.25rem;
  font-size: 0.875rem;
}

.project-impact li {
  margin-bottom: var(--space-xs);
}

.project-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--border);
}

.project-links a {
  font-size: 0.875rem;
  font-weight: 500;
}

/* ============================================
   Skills
   ============================================ */

.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

@media (min-width: 640px) {
  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.skill-card ul {
  margin: 0;
  padding-left: 1.25rem;
}

.skill-card li {
  margin-bottom: var(--space-sm);
}

/* ============================================
   Contact
   ============================================ */

.contact-lead {
  margin: 0 0 var(--space-xl);
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 40ch;
}

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

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-weight: 500;
  transition: background var(--duration-fast), border-color var(--duration-fast), color var(--duration-fast);
}

.contact-link:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  color: var(--accent);
}

.contact-icon {
  display: inline-flex;
  flex-shrink: 0;
}

.contact-icon svg {
  width: 20px;
  height: 20px;
}

.contact-note {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin: 0;
}

/* ============================================
   Footer
   ============================================ */

.site-footer {
  padding: var(--space-xl) var(--space-lg);
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.site-footer .container {
  text-align: center;
}

.site-footer p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}