/* ==========================================================================
   Sulthana Thazneem E. A. - High-End Developer Portfolio
   Typography, Variables, Base Styling, and Core Layout
   ========================================================================== */

:root {
  /* Color System */
  --bg-primary: #08090d;
  --bg-surface: #0e121a;
  --bg-surface-elevated: #141924;
  --bg-surface-hover: #1b2232;
  --bg-glass: rgba(14, 18, 26, 0.85);

  --border-subtle: #192030;
  --border-color: #232d42;
  --border-active: #00e5ff;

  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #8492a6;
  --text-faint: #475569;

  /* Single Restrained Accent Color */
  --accent-cyan: #00e5ff;
  --accent-cyan-dim: rgba(0, 229, 255, 0.12);
  --accent-cyan-border: rgba(0, 229, 255, 0.28);
  --accent-blue-subtle: #38bdf8;

  /* Status Colors */
  --status-success: #10b981;
  --status-warning: #f59e0b;

  /* Typography */
  --font-heading: 'Space Grotesk', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Layout Spacing */
  --container-max: 1200px;
  --container-narrow: 860px;
  --header-height: 72px;
  --section-spacing: 120px;
  --card-radius: 10px;
  --chip-radius: 6px;

  /* Transitions */
  --transition-fast: 0.18s ease;
  --transition-normal: 0.26s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-slow: 0.45s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 24px);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.65;
  background-color: var(--bg-primary);
  color: var(--text-secondary);
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
}

/* Subtle Technical Grid Background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    linear-gradient(to right, rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: -1;
}

/* Accessible Skip Link */
.skip-to-content {
  position: absolute;
  top: -100px;
  left: 20px;
  background: var(--accent-cyan);
  color: #08090d;
  padding: 8px 16px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  text-decoration: none;
  z-index: 9999;
  border-radius: 4px;
  transition: top 0.2s ease;
}

.skip-to-content:focus {
  top: 20px;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

.container-narrow {
  width: 100%;
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography Standards */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

p:last-child {
  margin-bottom: 0;
}

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

a:hover {
  color: #67e8f9;
}

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

/* Focus Visible Accessibility */
:focus-visible {
  outline: 2px solid var(--accent-cyan);
  outline-offset: 3px;
}

/* Section Header Structure */
.section-wrapper {
  padding: var(--section-spacing) 0;
  position: relative;
  border-bottom: 1px solid var(--border-subtle);
}

.section-wrapper:last-of-type {
  border-bottom: none;
}

.section-header {
  margin-bottom: 48px;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-cyan);
  margin-bottom: 12px;
}

.section-tag::before {
  content: '//';
  opacity: 0.6;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: -0.03em;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 680px;
  line-height: 1.6;
}

/* Engineering Badges & Monospace Accents */
.tech-chip {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: var(--chip-radius);
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.tech-chip:hover {
  border-color: var(--accent-cyan-border);
  color: var(--accent-cyan);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 12px 24px;
  border-radius: 6px;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--accent-cyan);
  color: #08090d;
  font-weight: 700;
}

.btn-primary:hover {
  background-color: #38bdf8;
  color: #08090d;
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(0, 229, 255, 0.25);
}

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

.btn-secondary:hover {
  border-color: var(--accent-cyan-border);
  background-color: var(--bg-surface-hover);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.85rem;
}

.btn-icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  fill: currentColor;
}

/* ==========================================================================
   Navigation Bar
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background-color: var(--bg-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  transition: border-color var(--transition-fast);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.brand-text {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.brand-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 2px 8px;
  background-color: var(--accent-cyan-dim);
  border: 1px solid var(--accent-cyan-border);
  color: var(--accent-cyan);
  border-radius: 4px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-link {
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  position: relative;
  padding: 8px 0;
  transition: color var(--transition-fast);
}

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--accent-cyan);
}

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

.nav-github-btn {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 7px 14px;
  border-radius: 5px;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all var(--transition-fast);
}

.nav-github-btn:hover {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
}

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background-color: var(--bg-surface);
  cursor: pointer;
  z-index: 1010;
}

.mobile-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--text-primary);
  transition: all var(--transition-fast);
}

.mobile-toggle.is-active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-toggle.is-active span:nth-child(2) {
  opacity: 0;
}

.mobile-toggle.is-active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  padding-top: 80px;
  padding-bottom: 90px;
  border-bottom: 1px solid var(--border-subtle);
  position: relative;
}

.hero-content {
  max-width: 900px;
  margin-bottom: 50px;
}

.hero-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 5px 12px;
  border-radius: 20px;
  background-color: var(--accent-cyan-dim);
  border: 1px solid var(--accent-cyan-border);
  color: var(--accent-cyan);
  margin-bottom: 24px;
}

.hero-status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--accent-cyan);
  box-shadow: 0 0 8px var(--accent-cyan);
  animation: pulseDot 2.2s infinite;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.hero-name {
  font-size: clamp(2.8rem, 6.5vw, 5rem);
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.05;
  letter-spacing: -0.04em;
  margin-bottom: 16px;
  text-transform: uppercase;
}

.hero-role-title {
  font-size: clamp(1.25rem, 2.8vw, 1.85rem);
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.hero-role-title .highlight {
  color: var(--accent-cyan);
}

.hero-summary {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 720px;
  line-height: 1.65;
  margin-bottom: 36px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 30px;
}

.hero-secondary-links {
  display: flex;
  align-items: center;
  gap: 24px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.hero-secondary-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  border-bottom: 1px dotted var(--border-color);
  padding-bottom: 2px;
}

.hero-secondary-links a:hover {
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
}

/* ==========================================================================
   About Section
   ========================================================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 56px;
  align-items: start;
}

.about-text-lead {
  font-size: 1.25rem;
  color: var(--text-primary);
  line-height: 1.65;
  margin-bottom: 24px;
}

.about-quote-card {
  margin: 28px 0;
  padding: 24px;
  background-color: var(--bg-surface);
  border-left: 3px solid var(--accent-cyan);
  border-radius: 0 var(--card-radius) var(--card-radius) 0;
}

.about-quote-card p {
  font-size: 1.05rem;
  color: var(--text-primary);
  font-weight: 500;
  line-height: 1.6;
  font-style: italic;
}

.about-metrics {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.metric-panel {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--card-radius);
  padding: 24px;
  transition: border-color var(--transition-fast);
}

.metric-panel:hover {
  border-color: var(--border-active);
}

.metric-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.metric-title {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.metric-code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent-cyan);
}

.metric-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 992px) {
  :root {
    --section-spacing: 90px;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

@media (max-width: 768px) {
  :root {
    --section-spacing: 70px;
    --header-height: 64px;
  }

  .mobile-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background-color: var(--bg-primary);
    flex-direction: column;
    align-items: flex-start;
    padding: 36px 28px;
    gap: 24px;
    transform: translateX(100%);
    transition: transform var(--transition-normal);
    border-top: 1px solid var(--border-subtle);
    z-index: 999;
  }

  .nav-menu.is-open {
    transform: translateX(0);
  }

  .nav-link {
    font-size: 1.25rem;
    width: 100%;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-subtle);
  }

  .hero-cta-group {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-cta-group .btn {
    width: 100%;
  }

  .hero-secondary-links {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
}