/* ============================================
   NovaTech Solutions — Main Stylesheet
   File: assets/css/styles.css
   ============================================ */

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

:root {
  /* Colors */
  --color-primary: #0A1F3F;
  --color-secondary: #132E5B;
  --color-accent: #2D7FF9;
  --color-accent-hover: #1B6AE0;
  --color-background: #F4F6F9;
  --color-white: #FFFFFF;
  --color-text: #1F2937;
  --color-text-light: #6B7280;
  --color-error: #EF4444;
  --color-success: #10B981;
  
  /* Typography */
  --font-heading: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
  
  /* Spacing */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 60px;
  --space-2xl: 80px;
  
  /* Layout */
  --max-width: 1200px;
  --nav-height: 72px;
  
  /* UI */
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.08);
  --shadow-lg: 0 10px 40px rgba(0,0,0,0.12);
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

/* RESET & BASE */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background: var(--color-background);
  color: var(--color-text);
  line-height: 1.6;
  overflow-x: hidden;
}
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; }

/* LAYOUT UTILITIES */
.container { width: 100%; max-width: var(--max-width); margin: 0 auto; padding: 0 var(--space-md); }
.section { padding: var(--space-2xl) 0; }
.text-center { text-align: center; }
.flex-between { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: var(--space-md); }
.grid { display: grid; gap: var(--space-lg); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* BUTTONS */
.btn {
  display: inline-block; padding: 12px 28px; border-radius: var(--radius-md);
  font-weight: 600; transition: var(--transition-fast); cursor: pointer; text-align: center;
}
.btn-primary { background: var(--color-accent); color: var(--color-white); }
.btn-primary:hover { background: var(--color-accent-hover); transform: translateY(-2px); }
.btn-outline { background: transparent; border: 2px solid var(--color-accent); color: var(--color-accent); }
.btn-outline:hover { background: var(--color-accent); color: var(--color-white); }

/* NAVIGATION */
#main-header {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  background: var(--color-primary); transition: var(--transition-normal);
}
#main-header.scrolled { background: rgba(10, 31, 63, 0.95); box-shadow: var(--shadow-md); }
nav { height: var(--nav-height); display: flex; justify-content: space-between; align-items: center; }
.logo { font-family: var(--font-heading); font-size: 1.5rem; font-weight: 700; color: var(--color-white); }
.logo span { color: var(--color-accent); }

.nav-menu { display: flex; gap: var(--space-md); align-items: center; }
.nav-link { color: var(--color-white); font-weight: 500; padding: 4px 0; position: relative; transition: var(--transition-fast); }
.nav-link:hover, .nav-link.active { color: var(--color-accent); }
.nav-link::after {
  content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px;
  background: var(--color-accent); transition: var(--transition-fast);
}
.nav-link:hover::after, .nav-link.active::after { width: 100%; }

/* Mobile Nav */
.menu-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.hamburger, .hamburger::before, .hamburger::after {
  display: block; width: 25px; height: 3px; background: var(--color-white);
  position: relative; transition: var(--transition-fast);
}
.hamburger::before, .hamburger::after { content: ''; position: absolute; }
.hamburger::before { top: -8px; }
.hamburger::after { top: 8px; }
.menu-toggle.active .hamburger { background: transparent; }
.menu-toggle.active .hamburger::before { transform: rotate(45deg); top: 0; }
.menu-toggle.active .hamburger::after { transform: rotate(-45deg); top: 0; }

/* HERO */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 50%, var(--color-accent) 100%);
  padding: 120px 0 80px; text-align: center; color: var(--color-white);
}
.hero h1 { font-family: var(--font-heading); font-size: 3.5rem; font-weight: 700; margin-bottom: var(--space-sm); line-height: 1.2; }
.hero p { font-size: 1.2rem; max-width: 650px; margin: 0 auto var(--space-md); color: rgba(255,255,255,0.9); }
.hero-buttons { display: flex; justify-content: center; gap: var(--space-sm); flex-wrap: wrap; }
.section-subtitle { font-size: 0.85rem; font-weight: 600; text-transform: uppercase; letter-spacing: 2px; color: var(--color-accent); margin-bottom: var(--space-xs); }
.section-title { font-family: var(--font-heading); font-size: 2.5rem; font-weight: 700; color: var(--color-text); margin-bottom: var(--space-sm); }
.section-text { color: var(--color-text-light); max-width: 700px; margin: 0 auto var(--space-lg); }

/* CARDS */
.card {
  background: var(--color-white); border-radius: var(--radius-lg); padding: var(--space-lg);
  box-shadow: var(--shadow-sm); transition: var(--transition-normal); border: 1px solid #e5e7eb;
}
.card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); border-color: var(--color-accent); }
.card h3 { font-family: var(--font-heading); font-size: 1.25rem; margin-bottom: var(--space-xs); }
.card p { color: var(--color-text-light); margin-bottom: var(--space-sm); }
.card-icon { width: 48px; height: 48px; background: #f3f4f6; border-radius: var(--radius-md); display: flex; align-items: center; justify-content: center; margin-bottom: var(--space-sm); font-size: 1.5rem; }

/* STATS */
.stats-container { background: var(--color-white); padding: var(--space-xl) 0; }
.stat-item { text-align: center; }
.stat-number { font-family: var(--font-heading); font-size: 3rem; font-weight: 700; color: var(--color-accent); display: block; }
.stat-label { color: var(--color-text-light); font-size: 0.9rem; }

/* TEAM */
.team-card { background: var(--color-white); border-radius: var(--radius-lg); padding: var(--space-md); text-align: center; box-shadow: var(--shadow-sm); transition: var(--transition-normal); }
.team-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
.team-photo { width: 120px; height: 120px; border-radius: 50%; object-fit: cover; margin: 0 auto var(--space-sm); border: 3px solid var(--color-white); box-shadow: var(--shadow-sm); }
.team-name { font-family: var(--font-heading); font-weight: 700; margin-bottom: 4px; }
.team-role { color: var(--color-accent); font-size: 0.85rem; margin-bottom: var(--space-xs); }
.team-bio { font-size: 0.85rem; color: var(--color-text-light); }

/* ACCORDION */
.accordion-item { background: var(--color-white); border-radius: var(--radius-md); margin-bottom: 12px; box-shadow: var(--shadow-sm); overflow: hidden; }
.accordion-header {
  width: 100%; padding: var(--space-md); background: var(--color-white); border: none; text-align: left;
  font-size: 1rem; font-weight: 600; color: var(--color-text); cursor: pointer;
  display: flex; justify-content: space-between; align-items: center; transition: var(--transition-fast);
}
.accordion-header:hover { background: #f8f9fa; }
.accordion-item.active .accordion-header { background: var(--color-accent); color: var(--color-white); }
.accordion-header span { font-size: 1.5rem; font-weight: 300; transition: transform 0.3s ease; }
.accordion-item.active .accordion-header span { transform: rotate(45deg); }
.accordion-content { max-height: 0; overflow: hidden; transition: max-height 0.3s ease-out, padding 0.3s ease; padding: 0 var(--space-md); }
.accordion-item.active .accordion-content { max-height: 500px; padding: var(--space-md); }
.accordion-content ul { padding-left: 20px; margin-top: 10px; }
.accordion-content li { color: var(--color-text-light); margin-bottom: 6px; }

/* FORM VALIDATION */
.form-group { margin-bottom: var(--space-md); }
.form-group label { display: block; font-weight: 500; margin-bottom: 6px; }
.form-group input, .form-group textarea {
  width: 100%; padding: 12px; border: 1px solid #d1d5db; border-radius: var(--radius-md);
  font-family: inherit; font-size: 0.95rem; transition: var(--transition-fast);
}
.form-group input:focus, .form-group textarea:focus { outline: none; border-color: var(--color-accent); box-shadow: 0 0 0 3px rgba(45, 127, 249, 0.15); }
.form-error { display: block; color: var(--color-error); font-size: 0.8rem; margin-top: 4px; min-height: 16px; }
.form-success { background: var(--color-success); color: var(--color-white); padding: var(--space-lg); border-radius: var(--radius-md); text-align: center; }

/* PORTFOLIO FILTER */
.filter { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin-bottom: var(--space-lg); }
.filter-btn {
  padding: 8px 20px; border-radius: 30px; background: var(--color-white); border: 1px solid #e5e7eb;
  color: var(--color-text-light); font-weight: 500; transition: var(--transition-fast);
}
.filter-btn:hover, .filter-btn.active { background: var(--color-accent); color: var(--color-white); border-color: var(--color-accent); }

/* FOOTER */
#main-footer { background: var(--color-primary); color: var(--color-text-light); padding-top: var(--space-xl); }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1.2fr; gap: var(--space-lg); padding-bottom: var(--space-lg); border-bottom: 1px solid rgba(255,255,255,0.1); }
.footer-heading { font-size: 0.9rem; font-weight: 700; color: var(--color-white); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: var(--space-sm); }
.footer-text, .footer-links a { color: var(--color-text-light); font-size: 0.9rem; line-height: 1.8; }
.footer-links a { transition: var(--transition-fast); display: inline-block; }
.footer-links a:hover { color: var(--color-accent); transform: translateX(3px); }
.footer-bottom { padding: var(--space-md) 0; }
.social-icons { display: flex; gap: 12px; }
.social-icon {
  width: 36px; height: 36px; border-radius: 50%; background: rgba(255,255,255,0.08);
  display: flex; align-items: center; justify-content: center; color: var(--color-text-light); transition: var(--transition-fast);
}
.social-icon:hover { background: var(--color-accent); color: var(--color-white); transform: translateY(-2px); }

/* BONUS: Scroll to Top & Dark Mode */
.scroll-top-btn {
  position: fixed; bottom: 30px; right: 30px; width: 48px; height: 48px; border-radius: 50%;
  background: var(--color-accent); color: var(--color-white); display: flex; align-items: center; justify-content: center;
  opacity: 0; pointer-events: none; transition: var(--transition-normal); z-index: 99;
}
.scroll-top-btn.visible { opacity: 1; pointer-events: auto; }
body.dark-mode {
  --color-background: #0F172A; --color-white: #1E293B; --color-text: #E2E8F0;
  --color-text-light: #94A3B8; --color-primary: #0B1324; --color-secondary: #132E5B;
}
body.dark-mode .card, body.dark-mode .accordion-item, body.dark-mode .form-group input,
body.dark-mode .form-group textarea { background: #1E293B; border-color: #334155; color: var(--color-text); }

/* RESPONSIVE */
@media (max-width: 992px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .hero h1 { font-size: 2.8rem; }
  .section-title { font-size: 2rem; }
}
@media (max-width: 768px) {
  .menu-toggle { display: block; }
  .nav-menu {
    display: none; position: absolute; top: var(--nav-height); left: 0; width: 100%;
    background: var(--color-primary); flex-direction: column; padding: var(--space-md);
    box-shadow: var(--shadow-lg); text-align: center;
  }
  .nav-menu.active { display: flex; }
  .nav-link { padding: 10px 0; width: 100%; }
  .grid-3, .grid-2, .grid-4, .footer-grid { grid-template-columns: 1fr; }
  .hero { padding: 100px 0 60px; }
  .hero h1 { font-size: 2.2rem; }
  .contact-wrapper { grid-template-columns: 1fr; }
  #main-header { position: sticky; }
}
@media (max-width: 480px) {
  .hero h1 { font-size: 1.8rem; }
  .btn { width: 100%; }
  .hero-buttons { flex-direction: column; }
  .filter-btn { font-size: 0.8rem; padding: 6px 14px; }
}