/* ═══════════════════════════════════════════════
   UPENDRA DEV PLATFORM — Core Design System
   ═══════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ─── CSS Custom Properties ─── */
:root {
  /* Dark theme (default) */
  --bg:            #0d1b2a;
  --bg-alt:        #0a1628;
  --surface:       #1b2d40;
  --surface-2:     #223347;
  --surface-3:     #2a3f55;
  --border:        rgba(255, 255, 255, 0.08);
  --border-accent: rgba(0, 212, 255, 0.3);

  --text:          #e2e8f0;
  --text-muted:    #64748b;
  --text-subtle:   #94a3b8;

  --accent:        #00d4ff;
  --accent-rgb:    0, 212, 255;
  --accent2:       #7c3aed;
  --accent2-rgb:   124, 58, 237;
  --success:       #22c55e;
  --warning:       #f59e0b;
  --danger:        #ef4444;

  /* Gradients */
  --grad-primary:  linear-gradient(135deg, #00d4ff 0%, #7c3aed 100%);
  --grad-hero:     linear-gradient(135deg, #0d1b2a 0%, #1b2d40 50%, #0a1628 100%);
  --grad-card:     linear-gradient(135deg, rgba(27,45,64,0.9) 0%, rgba(34,51,71,0.9) 100%);

  /* Shadows */
  --shadow-sm:     0 1px 3px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.4);
  --shadow-md:     0 4px 6px rgba(0,0,0,0.3), 0 2px 4px rgba(0,0,0,0.4);
  --shadow-lg:     0 10px 15px rgba(0,0,0,0.4), 0 4px 6px rgba(0,0,0,0.3);
  --shadow-xl:     0 20px 25px rgba(0,0,0,0.5), 0 10px 10px rgba(0,0,0,0.3);
  --shadow-glow:   0 0 30px rgba(0, 212, 255, 0.15);
  --shadow-glow2:  0 0 30px rgba(124, 58, 237, 0.2);

  /* 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;
  --space-4xl: 6rem;

  /* Border radius */
  --radius-sm:  0.375rem;
  --radius-md:  0.75rem;
  --radius-lg:  1rem;
  --radius-xl:  1.5rem;
  --radius-2xl: 2rem;
  --radius-full: 9999px;

  /* Transitions */
  --ease:       cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out:   cubic-bezier(0, 0, 0.2, 1);
  --ease-in:    cubic-bezier(0.4, 0, 1, 1);
  --transition: 0.25s var(--ease);
  --transition-slow: 0.4s var(--ease);

  /* Font families */
  --font-heading: 'Space Grotesk', system-ui, sans-serif;
  --font-body:    'Inter', system-ui, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', monospace;

  /* Nav height */
  --nav-height: 70px;
}

/* Light theme */
[data-theme="light"] {
  --bg:         #f4f6fb;
  --bg-alt:     #eef1f8;
  --surface:    #ffffff;
  --surface-2:  #f8faff;
  --surface-3:  #eef1f8;
  --border:     rgba(0, 0, 0, 0.08);
  --border-accent: rgba(0, 119, 204, 0.3);

  --text:       #1e293b;
  --text-muted: #64748b;
  --text-subtle:#94a3b8;

  --accent:     #0077cc;
  --accent-rgb: 0, 119, 204;
  --accent2:    #6d28d9;
  --accent2-rgb: 109, 40, 217;

  --grad-primary: linear-gradient(135deg, #0077cc 0%, #6d28d9 100%);
  --grad-hero:    linear-gradient(135deg, #f4f6fb 0%, #eef1f8 100%);
  --grad-card:    linear-gradient(135deg, rgba(255,255,255,0.95) 0%, rgba(244,246,251,0.95) 100%);

  --shadow-sm:  0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md:  0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg:  0 10px 15px rgba(0,0,0,0.08), 0 4px 6px rgba(0,0,0,0.06);
  --shadow-xl:  0 20px 25px rgba(0,0,0,0.1), 0 10px 10px rgba(0,0,0,0.04);
  --shadow-glow: 0 0 30px rgba(0, 119, 204, 0.12);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color var(--transition-slow), color var(--transition-slow);
}

/* ─── Scrollbar ─── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb {
  background: var(--surface-3);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover { background: var(--accent); }

/* ─── Typography ─── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); }
h3 { font-size: clamp(1.15rem, 2vw, 1.5rem); }
h4 { font-size: 1.125rem; }

p { line-height: 1.75; color: var(--text-subtle); }

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

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

code, pre {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

pre {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  overflow-x: auto;
}

/* ─── Layout Utilities ─── */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section {
  padding: var(--space-4xl) 0;
}

.section-sm {
  padding: var(--space-2xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.section-header h2 {
  position: relative;
  display: inline-block;
  margin-bottom: var(--space-md);
}

.section-header h2::after {
  content: '';
  display: block;
  width: 60px;
  height: 3px;
  background: var(--grad-primary);
  border-radius: var(--radius-full);
  margin: var(--space-sm) auto 0;
}

.section-header p {
  max-width: 600px;
  margin: 0 auto;
}

/* ─── Grid ─── */
.grid { display: grid; }
.grid-2 { grid-template-columns: repeat(2, 1fr); gap: var(--space-xl); }
.grid-3 { grid-template-columns: repeat(3, 1fr); gap: var(--space-xl); }
.grid-auto { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--space-xl); }

/* ─── Flex ─── */
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.flex-col { display: flex; flex-direction: column; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }

/* ─── Glassmorphism Card ─── */
.card {
  background: var(--grad-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl), var(--shadow-glow);
  border-color: var(--border-accent);
}

/* ─── Buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-full);
  border: none;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
  line-height: 1;
}

.btn-primary {
  background: var(--grad-primary);
  color: #fff;
  box-shadow: 0 4px 15px rgba(var(--accent-rgb), 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(var(--accent-rgb), 0.45);
  color: #fff;
}

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

.btn-outline:hover {
  background: rgba(var(--accent-rgb), 0.1);
  color: var(--accent);
  transform: translateY(-2px);
}

.btn-ghost {
  background: var(--surface-2);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-ghost:hover {
  background: var(--surface-3);
  color: var(--text);
  border-color: var(--border-accent);
}

.btn-success {
  background: var(--success);
  color: #fff;
}
.btn-success:hover {
  opacity: 0.9;
  transform: translateY(-2px);
  color: #fff;
}

.btn-danger {
  background: var(--danger);
  color: #fff;
}
.btn-danger:hover {
  opacity: 0.9;
  transform: translateY(-2px);
  color: #fff;
}

.btn-sm {
  padding: 0.4rem 1rem;
  font-size: 0.85rem;
}

.btn-lg {
  padding: 0.85rem 2rem;
  font-size: 1.05rem;
}

/* ─── Badge / Chip ─── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 0.2rem 0.65rem;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-weight: 600;
  background: rgba(var(--accent-rgb), 0.12);
  color: var(--accent);
  border: 1px solid rgba(var(--accent-rgb), 0.2);
}

.badge-purple {
  background: rgba(var(--accent2-rgb), 0.12);
  color: var(--accent2);
  border-color: rgba(var(--accent2-rgb), 0.25);
}

.badge-success {
  background: rgba(34, 197, 94, 0.12);
  color: var(--success);
  border-color: rgba(34, 197, 94, 0.25);
}

/* ─── Form Controls ─── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-bottom: var(--space-lg);
}

.form-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-subtle);
  letter-spacing: 0.01em;
}

.form-control {
  width: 100%;
  padding: 0.65rem var(--space-md);
  background: var(--surface-2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  transition: border-color var(--transition), box-shadow var(--transition);
  resize: vertical;
}

.form-control:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(var(--accent-rgb), 0.15);
}

.form-control::placeholder {
  color: var(--text-muted);
}

textarea.form-control {
  min-height: 180px;
  font-size: 0.875rem;
  line-height: 1.6;
}

.form-check {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
  cursor: pointer;
}

.form-check input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
  cursor: pointer;
  flex-shrink: 0;
}

.form-check label {
  font-size: 0.875rem;
  color: var(--text-subtle);
  cursor: pointer;
}

select.form-control {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='%2364748b' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10l-5 5z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  background-size: 16px;
  padding-right: 40px;
}

/* ─── Divider ─── */
.divider {
  height: 1px;
  background: var(--border);
  margin: var(--space-xl) 0;
}

/* ─── Tag / Skill Chip ─── */
.chip {
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 500;
  background: var(--surface-2);
  color: var(--text-subtle);
  border: 1px solid var(--border);
  transition: all var(--transition);
}

.chip:hover {
  background: rgba(var(--accent-rgb), 0.1);
  color: var(--accent);
  border-color: rgba(var(--accent-rgb), 0.3);
  transform: translateY(-1px);
}

/* ─── Toast / Alert ─── */
.toast {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  padding: var(--space-md) var(--space-lg);
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  font-size: 0.9rem;
  z-index: 9999;
  transform: translateY(100px);
  opacity: 0;
  transition: all var(--transition-slow);
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

.toast-success { border-left: 4px solid var(--success); }
.toast-error   { border-left: 4px solid var(--danger); }

/* ─── Copy button state ─── */
.btn-copy-success {
  background: var(--success) !important;
  color: #fff !important;
}

/* ─── Scroll reveal ─── */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

.reveal-stagger > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s var(--ease-out), transform 0.5s var(--ease-out);
}

.reveal-stagger.visible > *:nth-child(1) { opacity:1; transform:none; transition-delay:0ms; }
.reveal-stagger.visible > *:nth-child(2) { opacity:1; transform:none; transition-delay:80ms; }
.reveal-stagger.visible > *:nth-child(3) { opacity:1; transform:none; transition-delay:160ms; }
.reveal-stagger.visible > *:nth-child(4) { opacity:1; transform:none; transition-delay:240ms; }
.reveal-stagger.visible > *:nth-child(5) { opacity:1; transform:none; transition-delay:320ms; }
.reveal-stagger.visible > *:nth-child(6) { opacity:1; transform:none; transition-delay:400ms; }
.reveal-stagger.visible > *:nth-child(7) { opacity:1; transform:none; transition-delay:480ms; }
.reveal-stagger.visible > *:nth-child(8) { opacity:1; transform:none; transition-delay:560ms; }

/* ─── Section label ─── */
.section-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--space-md);
}

.section-label::before {
  content: '';
  display: block;
  width: 20px;
  height: 2px;
  background: var(--accent);
  border-radius: var(--radius-full);
}

/* ─── Responsive ─── */
@media (max-width: 1024px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .container { padding: 0 var(--space-md); }
  .section { padding: var(--space-3xl) 0; }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .btn-lg { padding: 0.75rem 1.5rem; font-size: 1rem; }
  h1 { font-size: clamp(1.75rem, 8vw, 2.5rem); }
}

@media (max-width: 480px) {
  .container { padding: 0 var(--space-md); }
}