/* 
 * Sinh Trắc Việt Talent - Design System & Styles
 * Colors: Trust Blue, Teal, Accent Gold
 * Typography: Inter (Sans-serif) for modern medical/edu feel.
 */

:root {
  --color-primary: #0A4D68;   /* Trust Blue */
  --color-secondary: #088395; /* Teal */
  --color-accent: #F2CD5C;    /* Gold */
  --color-accent-light: #F2DEBA;
  
  --color-dark: #0f172a;
  --color-text: #334155;
  --color-text-muted: #64748b;
  --color-bg: #f8fafc;
  --color-white: #ffffff;
  --color-border: #e2e8f0;

  --font-main: 'Inter', system-ui, -apple-system, sans-serif;
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 24px;
  
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: var(--font-main);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

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

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

h1, h2, h3, h4, h5, h6 {
  color: var(--color-dark);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.container--narrow {
  max-width: 800px;
}

.section {
  padding: 80px 0;
}

.section--bg {
  background-color: var(--color-white);
}

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

.section-header h2 {
  font-size: 2.5rem;
  color: var(--color-primary);
  margin-bottom: 16px;
}

.section-header p {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-align: center;
}

.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.btn--primary:hover {
  background-color: var(--color-dark);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn--accent {
  background-color: var(--color-accent);
  color: var(--color-dark);
}

.btn--accent:hover {
  background-color: #e5b945;
  color: var(--color-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid var(--color-border);
  transition: var(--transition);
}

.site-header__inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.site-logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  gap: 12px;
}

.site-logo__icon {
  width: 40px;
  height: 40px;
  background: var(--color-primary);
  color: white;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.site-nav a {
  color: var(--color-text);
  font-weight: 500;
}

.site-nav a:hover,
.site-nav a.active {
  color: var(--color-primary);
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.mobile-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-dark);
  margin-bottom: 5px;
  transition: var(--transition);
}

.mobile-toggle span:last-child {
  margin-bottom: 0;
}

/* Hero Section */
.hero {
  padding: 160px 0 100px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  color: var(--color-white);
  overflow: hidden;
  position: relative;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -50px;
  left: 0;
  width: 100%;
  height: 100px;
  background: var(--color-bg);
  transform: skewY(-2deg);
}

.hero__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero__content h1 {
  font-size: 3.5rem;
  color: var(--color-white);
  margin-bottom: 24px;
}

.hero__content h1 span {
  color: var(--color-accent);
}

.hero__content p {
  font-size: 1.25rem;
  margin-bottom: 32px;
  opacity: 0.9;
}

.hero__actions {
  display: flex;
  gap: 16px;
}

.hero__image img {
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  transform: translateY(0);
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0% { transform: translateY(0px); }
  50% { transform: translateY(-20px); }
  100% { transform: translateY(0px); }
}

/* Cards */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
}

.service-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  padding: 40px 32px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid var(--color-border);
  text-align: center;
}

.service-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-secondary);
}

.service-card__icon {
  width: 80px;
  height: 80px;
  background: var(--color-bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 24px;
  font-size: 2rem;
  color: var(--color-secondary);
}

.service-card h3 {
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.service-card p {
  color: var(--color-text-muted);
  margin-bottom: 24px;
}

/* Articles Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
}

.article-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.article-card__img-wrap {
  position: relative;
  padding-top: 60%;
  overflow: hidden;
}

.article-card__img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.article-card:hover .article-card__img {
  transform: scale(1.05);
}

.article-card__body {
  padding: 24px;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

.article-card__cat {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-secondary);
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.article-card__title {
  font-size: 1.25rem;
  margin-bottom: 12px;
  color: var(--color-dark);
}

.article-card__desc {
  color: var(--color-text-muted);
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-card__meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
  padding-top: 16px;
}

/* Call to Action */
.cta {
  background: var(--color-dark);
  color: var(--color-white);
  text-align: center;
  padding: 100px 0;
  border-radius: var(--radius-lg);
  margin: 80px 20px;
}

.cta h2 {
  color: var(--color-white);
  font-size: 2.5rem;
  margin-bottom: 24px;
}

.cta p {
  font-size: 1.25rem;
  opacity: 0.9;
  margin-bottom: 40px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* Footer */
.site-footer {
  background: var(--color-dark);
  color: var(--color-white);
  padding: 80px 0 24px;
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 60px;
  margin-bottom: 60px;
}

.footer-brand__logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-white);
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
}

.footer-brand p {
  color: #94a3b8;
  margin-bottom: 24px;
  max-width: 300px;
}

.site-footer h4 {
  color: var(--color-white);
  margin-bottom: 24px;
}

.site-footer ul {
  list-style: none;
}

.site-footer ul li {
  margin-bottom: 12px;
}

.site-footer a {
  color: #94a3b8;
}

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

.site-footer__bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.1);
  color: #94a3b8;
  font-size: 0.875rem;
}

/* Content Pages (Blog Post / Services) */
.page-header {
  padding: 160px 0 80px;
  background: var(--color-white);
  text-align: center;
}

.page-header__meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  color: var(--color-text-muted);
  margin-bottom: 24px;
}

.page-header h1 {
  font-size: 3rem;
  max-width: 800px;
  margin: 0 auto;
}

.page-cover {
  margin-bottom: 60px;
}

.page-cover img {
  width: 100%;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.content-body {
  font-size: 1.125rem;
  line-height: 1.8;
}

.content-body h2 {
  font-size: 2rem;
  margin: 48px 0 24px;
  color: var(--color-primary);
}

.content-body h3 {
  font-size: 1.5rem;
  margin: 32px 0 16px;
}

.content-body p {
  margin-bottom: 24px;
}

.content-body ul, .content-body ol {
  margin-bottom: 24px;
  padding-left: 24px;
}

.content-body li {
  margin-bottom: 12px;
}

.content-body blockquote {
  border-left: 4px solid var(--color-accent);
  padding-left: 24px;
  font-style: italic;
  font-size: 1.25rem;
  color: var(--color-primary);
  margin: 40px 0;
  background: var(--color-bg);
  padding: 24px;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.toc-box {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
  margin: 40px 0;
  box-shadow: var(--shadow-sm);
}

.toc-box h3 {
  margin-top: 0;
  color: var(--color-dark);
}

.toc-box ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc-box a {
  color: var(--color-text);
  display: block;
  padding: 8px 0;
  border-bottom: 1px dashed var(--color-border);
}

.toc-box a:hover {
  color: var(--color-secondary);
  padding-left: 8px;
}

/* Responsive */
@media (max-width: 992px) {
  .hero__inner {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .hero__actions {
    justify-content: center;
  }
  .site-footer__grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .mobile-toggle {
    display: block;
  }
  .site-nav {
    position: fixed;
    top: 80px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 80px);
    background: var(--color-white);
    flex-direction: column;
    padding: 40px;
    transition: var(--transition);
  }
  .site-nav.active {
    left: 0;
  }
  .hero__content h1 {
    font-size: 2.5rem;
  }
  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}