/* ========================================
   4 Core Labs — Global Stylesheet
   Multi-Page Site v2.0
   ======================================== */

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

:root {
  --green: #00c896;
  --green-dark: #00a67a;
  --cyan: #00d4ff;
  --cyan-dark: #00b4d8;
  --dark: #0a0e1a;
  --dark2: #111827;
  --dark3: #1a2035;
  --light: #f0f4f8;
  --white: #ffffff;
  --gray: #94a3b8;
  --gray-dark: #475569;
  --orange: #f59e0b;
  --red: #ef4444;
  --purple: #8b5cf6;
  --gradient: linear-gradient(135deg, var(--green), var(--cyan));
  --gradient-dark: linear-gradient(135deg, var(--dark2), var(--dark));
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.25);
  --radius: 12px;
  --radius-sm: 8px;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-head: 'Space Grotesk', 'Inter', sans-serif;
}

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

body {
  font-family: var(--font-main);
  color: var(--dark2);
  background: var(--white);
  line-height: 1.7;
  overflow-x: hidden;
}

a { color: var(--green); text-decoration: none; transition: color .2s; }
a:hover { color: var(--cyan); }

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

/* --- Navigation --- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(0, 200, 150, 0.15);
  transition: all .3s;
}
.nav__container {
  max-width: 1280px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 24px; height: 68px;
}
.nav__logo {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--font-head); font-weight: 700; font-size: 1.25rem;
  color: var(--white) !important;
}
.nav__logo img { height: 36px; }

.nav__links {
  display: flex; align-items: center; gap: 6px; list-style: none;
}
.nav__links a {
  color: var(--gray); padding: 8px 14px; border-radius: var(--radius-sm);
  font-size: .875rem; font-weight: 500; transition: all .2s;
  white-space: nowrap;
}
.nav__links a:hover,
.nav__links a.active {
  color: var(--white); background: rgba(0, 200, 150, 0.12);
}
.nav__links a.active { color: var(--green); }

.nav__cta {
  background: var(--gradient); color: var(--white) !important;
  padding: 10px 20px !important; border-radius: var(--radius-sm) !important;
  font-weight: 600 !important;
}
.nav__cta:hover { opacity: .9; transform: translateY(-1px); }

/* Mobile menu */
.nav__toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.nav__toggle span {
  display: block; width: 24px; height: 2px; background: var(--white);
  margin: 5px 0; border-radius: 2px; transition: .3s;
}

@media (max-width: 900px) {
  .nav__toggle { display: block; }
  .nav__links {
    position: absolute; top: 68px; left: 0; right: 0;
    background: rgba(10, 14, 26, 0.98);
    flex-direction: column; padding: 16px; gap: 4px;
    border-bottom: 1px solid rgba(0,200,150,.15);
    display: none;
  }
  .nav__links.open { display: flex; }
  .nav__links a { padding: 12px 16px; width: 100%; }
}

/* --- Hero Section --- */
.hero {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  background: var(--dark); color: var(--white);
  position: relative; overflow: hidden; padding-top: 68px;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(ellipse at 30% 50%, rgba(0,200,150,0.12) 0%, transparent 60%),
              radial-gradient(ellipse at 70% 80%, rgba(0,212,255,0.08) 0%, transparent 50%);
}
.hero__content {
  position: relative; z-index: 1;
  max-width: 800px; text-align: center; padding: 40px 24px;
}
.hero__badge {
  display: inline-block; padding: 6px 16px; border-radius: 999px;
  background: rgba(0,200,150,0.15); border: 1px solid rgba(0,200,150,0.3);
  color: var(--green); font-size: .8rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: 1px; margin-bottom: 24px;
}
.hero h1 {
  font-family: var(--font-head); font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 800; line-height: 1.15; margin-bottom: 20px;
}
.hero h1 .gradient-text {
  background: var(--gradient); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
}
.hero p {
  font-size: 1.15rem; color: var(--gray); max-width: 600px;
  margin: 0 auto 36px; line-height: 1.8;
}
.hero__actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* Hero mini (for inner pages) */
.hero--mini { min-height: auto; padding: 120px 24px 80px; }
.hero--mini h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); }

/* --- Buttons --- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: var(--radius-sm);
  font-family: var(--font-main); font-size: .95rem; font-weight: 600;
  cursor: pointer; border: none; transition: all .25s;
}
.btn--primary {
  background: var(--gradient); color: var(--white);
  box-shadow: 0 4px 20px rgba(0,200,150,0.3);
}
.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(0,200,150,0.4); }
.btn--outline {
  background: transparent; color: var(--white);
  border: 2px solid rgba(255,255,255,0.2);
}
.btn--outline:hover { border-color: var(--green); color: var(--green); }
.btn--dark {
  background: var(--dark2); color: var(--white);
}
.btn--dark:hover { background: var(--dark3); }
.btn--green {
  background: var(--green); color: var(--white);
}
.btn--green:hover { background: var(--green-dark); }
.btn--sm { padding: 10px 20px; font-size: .85rem; }

/* --- Section Layout --- */
.section {
  padding: 100px 24px;
}
.section--dark { background: var(--dark); color: var(--white); }
.section--gray { background: var(--light); }
.section__header {
  max-width: 700px; margin: 0 auto 60px; text-align: center;
}
.section__label {
  display: inline-block; font-size: .8rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 2px;
  color: var(--green); margin-bottom: 12px;
}
.section--dark .section__label { color: var(--cyan); }
.section__title {
  font-family: var(--font-head); font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  font-weight: 700; margin-bottom: 16px; line-height: 1.25;
}
.section__desc {
  font-size: 1.05rem; color: var(--gray-dark); line-height: 1.8;
}
.section--dark .section__desc { color: var(--gray); }

.container { max-width: 1200px; margin: 0 auto; }

/* --- Card Grid --- */
.grid { display: grid; gap: 24px; }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid--4 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }

.card {
  background: var(--white); border-radius: var(--radius);
  padding: 32px; border: 1px solid rgba(0,0,0,0.06);
  transition: all .3s; position: relative;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.section--dark .card {
  background: var(--dark2); border-color: rgba(255,255,255,0.06);
}
.card__icon {
  width: 52px; height: 52px; border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; margin-bottom: 20px;
  background: rgba(0,200,150,0.1); color: var(--green);
}
.section--dark .card__icon { background: rgba(0,200,150,0.15); }
.card__icon--cyan { background: rgba(0,212,255,0.1); color: var(--cyan); }
.card__icon--orange { background: rgba(245,158,11,0.1); color: var(--orange); }
.card__icon--purple { background: rgba(139,92,246,0.1); color: var(--purple); }
.card h3 {
  font-family: var(--font-head); font-size: 1.2rem; font-weight: 700;
  margin-bottom: 10px;
}
.card p { color: var(--gray-dark); font-size: .95rem; line-height: 1.7; }
.section--dark .card p { color: var(--gray); }

/* --- Pricing --- */
.pricing-card {
  background: var(--white); border-radius: var(--radius);
  padding: 40px 32px; border: 1px solid rgba(0,0,0,0.08);
  text-align: center; transition: all .3s;
}
.pricing-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.pricing-card.featured {
  border: 2px solid var(--green); position: relative;
}
.pricing-card.featured::before {
  content: 'POPULAR'; position: absolute; top: -12px; left: 50%;
  transform: translateX(-50%); background: var(--gradient);
  color: var(--white); font-size: .7rem; font-weight: 700;
  padding: 4px 16px; border-radius: 999px; letter-spacing: 1px;
}
.pricing-card h3 {
  font-family: var(--font-head); font-size: 1.3rem; font-weight: 700;
  margin-bottom: 8px;
}
.pricing-card .price {
  font-family: var(--font-head); font-size: 2.8rem; font-weight: 800;
  color: var(--green); margin: 16px 0 4px;
}
.pricing-card .price span { font-size: 1rem; color: var(--gray); font-weight: 400; }
.pricing-card .price-desc { color: var(--gray); font-size: .9rem; margin-bottom: 24px; }
.pricing-card ul { list-style: none; text-align: left; margin-bottom: 32px; }
.pricing-card li {
  padding: 8px 0; border-bottom: 1px solid rgba(0,0,0,0.05);
  font-size: .95rem; display: flex; align-items: center; gap: 10px;
}
.pricing-card li::before { content: '✓'; color: var(--green); font-weight: 700; }

/* --- Features List --- */
.feature-row {
  display: grid; grid-template-columns: 1fr 1fr; gap: 60px;
  align-items: center; margin-bottom: 80px;
}
.feature-row:nth-child(even) .feature-row__visual { order: -1; }
.feature-row__text h3 {
  font-family: var(--font-head); font-size: 1.5rem; font-weight: 700;
  margin-bottom: 14px;
}
.feature-row__text p { color: var(--gray-dark); line-height: 1.8; margin-bottom: 20px; }
.feature-row__visual {
  background: var(--dark2); border-radius: var(--radius);
  padding: 40px; min-height: 280px; display: flex;
  align-items: center; justify-content: center;
  font-size: 4rem;
}
.section--dark .feature-row__visual { background: var(--dark3); }
.feature-row__tags { display: flex; flex-wrap: wrap; gap: 8px; }
.feature-row__tag {
  padding: 4px 12px; border-radius: 999px; font-size: .8rem;
  background: rgba(0,200,150,0.1); color: var(--green); font-weight: 500;
}

@media (max-width: 768px) {
  .feature-row { grid-template-columns: 1fr; gap: 24px; }
  .feature-row:nth-child(even) .feature-row__visual { order: 0; }
}

/* --- Stats Bar --- */
.stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 32px; text-align: center;
}
.stat__number {
  font-family: var(--font-head); font-size: 2.8rem; font-weight: 800;
  background: var(--gradient); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
}
.stat__label { color: var(--gray); font-size: .95rem; margin-top: 4px; }

/* --- Service Page Tabs --- */
.services-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 32px;
}
.service-block {
  background: var(--white); border-radius: var(--radius);
  padding: 36px; border: 1px solid rgba(0,0,0,0.06);
  transition: all .3s;
}
.service-block:hover { box-shadow: var(--shadow); }
.section--dark .service-block {
  background: var(--dark2); border-color: rgba(255,255,255,0.06);
}
.service-block h3 {
  font-family: var(--font-head); font-size: 1.25rem; font-weight: 700;
  margin-bottom: 8px; display: flex; align-items: center; gap: 12px;
}
.service-block h3 .icon { font-size: 1.4rem; }
.service-block .desc { color: var(--gray-dark); margin-bottom: 16px; line-height: 1.7; }
.section--dark .service-block .desc { color: var(--gray); }
.service-block .price-tag {
  font-family: var(--font-head); font-weight: 700; color: var(--green);
  font-size: 1.15rem; margin-bottom: 12px;
}

/* --- Programming Course Cards --- */
.course-card {
  background: var(--white); border-radius: var(--radius);
  overflow: hidden; border: 1px solid rgba(0,0,0,0.06);
  transition: all .3s;
}
.course-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.course-card__header {
  padding: 24px 28px 16px; display: flex; justify-content: space-between; align-items: center;
}
.course-card__level {
  padding: 4px 12px; border-radius: 999px; font-size: .75rem;
  font-weight: 600; text-transform: uppercase; letter-spacing: .5px;
}
.course-card__level--beginner { background: rgba(0,200,150,0.12); color: var(--green); }
.course-card__level--intermediate { background: rgba(0,212,255,0.12); color: var(--cyan); }
.course-card__level--advanced { background: rgba(245,158,11,0.12); color: var(--orange); }
.course-card__level--expert { background: rgba(239,68,68,0.12); color: var(--red); }
.course-card__body { padding: 0 28px 24px; }
.course-card__body h3 {
  font-family: var(--font-head); font-size: 1.15rem; font-weight: 700; margin-bottom: 8px;
}
.course-card__body p { color: var(--gray-dark); font-size: .9rem; line-height: 1.7; }
.course-card__tags {
  padding: 0 28px 24px; display: flex; flex-wrap: wrap; gap: 6px;
}
.course-card__tag {
  padding: 3px 10px; border-radius: 999px; font-size: .75rem;
  background: var(--light); color: var(--gray-dark); font-weight: 500;
}
.course-card__footer {
  padding: 16px 28px; border-top: 1px solid rgba(0,0,0,0.06);
  display: flex; justify-content: space-between; align-items: center;
}
.course-card__footer .duration { color: var(--gray); font-size: .85rem; }

/* --- Contact Form --- */
.contact {
  background: var(--dark); padding: 100px 24px; color: var(--white);
}
.contact__grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 60px;
  max-width: 1000px; margin: 0 auto;
}
.contact__info h3 {
  font-family: var(--font-head); font-size: 1.6rem; font-weight: 700; margin-bottom: 16px;
}
.contact__info p { color: var(--gray); line-height: 1.8; margin-bottom: 24px; }
.contact__detail {
  display: flex; align-items: center; gap: 14px; margin-bottom: 16px;
  font-size: .95rem;
}
.contact__detail .icon { font-size: 1.3rem; color: var(--green); }

.form { display: flex; flex-direction: column; gap: 16px; }
.form input, .form textarea, .form select {
  width: 100%; padding: 14px 18px; border-radius: var(--radius-sm);
  border: 1px solid rgba(255,255,255,0.1); background: var(--dark2);
  color: var(--white); font-family: var(--font-main); font-size: .95rem;
  transition: border-color .2s;
}
.form input:focus, .form textarea:focus, .form select:focus {
  outline: none; border-color: var(--green);
}
.form textarea { min-height: 120px; resize: vertical; }
.form .btn { align-self: flex-start; }
.form .status { font-size: .9rem; margin-top: 4px; }
.form .status.success { color: var(--green); }
.form .status.error { color: var(--red); }

@media (max-width: 768px) {
  .contact__grid { grid-template-columns: 1fr; gap: 40px; }
}

/* --- Footer --- */
.footer {
  background: var(--dark); color: var(--white);
  padding: 60px 24px 30px; border-top: 1px solid rgba(255,255,255,0.06);
}
.footer__grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px; max-width: 1200px; margin: 0 auto;
}
.footer h4 {
  font-family: var(--font-head); font-weight: 700; margin-bottom: 16px; font-size: 1rem;
}
.footer p { color: var(--gray); font-size: .9rem; line-height: 1.7; }
.footer ul { list-style: none; }
.footer li { margin-bottom: 10px; }
.footer li a { color: var(--gray); font-size: .9rem; transition: color .2s; }
.footer li a:hover { color: var(--green); }
.footer__bottom {
  max-width: 1200px; margin: 40px auto 0; padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.06);
  display: flex; justify-content: space-between; align-items: center;
  color: var(--gray); font-size: .85rem;
}
@media (max-width: 768px) {
  .footer__grid { grid-template-columns: 1fr 1fr; }
  .footer__bottom { flex-direction: column; gap: 12px; text-align: center; }
}

/* --- Animations --- */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeInUp .6s ease forwards; }
.fade-in-delay-1 { animation-delay: .15s; opacity: 0; }
.fade-in-delay-2 { animation-delay: .3s; opacity: 0; }
.fade-in-delay-3 { animation-delay: .45s; opacity: 0; }

/* --- Utility --- */
.text-center { text-align: center; }
.mt-40 { margin-top: 40px; }
.mb-40 { margin-bottom: 40px; }
.mt-60 { margin-top: 60px; }
.mb-60 { margin-bottom: 60px; }