/* PhysikHelfer - Main Stylesheet */
/* Colors: #0D47A1 (primary), #1565C0 (secondary), #29B6F6 (accent), #E3F2FD (light bg), #0A1628 (dark bg), #F8FAFC (white) */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Plus+Jakarta+Sans:wght@500;600;700;800&display=swap');

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

:root {
  --primary: #0D47A1;
  --secondary: #1565C0;
  --accent: #29B6F6;
  --light-bg: #E3F2FD;
  --dark-bg: #0A1628;
  --white: #F8FAFC;
  --text: #1e293b;
  --text-light: #64748b;
  --border: #e2e8f0;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
  --radius: 12px;
  --radius-sm: 8px;
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', sans-serif;
  color: var(--text);
  background: var(--white);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Plus Jakarta Sans', sans-serif;
  font-weight: 700;
  line-height: 1.3;
  color: var(--dark-bg);
}

a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--secondary); }

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

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

/* Header & Nav */
.header {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: 'Plus Jakarta Sans', sans-serif;
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--primary);
}

.logo svg { width: 36px; height: 36px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-weight: 500;
  color: var(--text);
  transition: all 0.2s;
}

.nav-links a:hover, .nav-links a.active {
  background: var(--light-bg);
  color: var(--primary);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.hamburger span {
  width: 24px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.3s;
}

/* Mobile Nav */
@media (max-width: 768px) {
  .hamburger { display: flex; }
  
  .nav-links {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    padding: 20px;
    gap: 8px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s;
  }
  
  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }
  
  .nav-links a { width: 100%; text-align: center; }
}

/* Breadcrumb */
.breadcrumb {
  padding: 16px 0;
  font-size: 0.875rem;
  color: var(--text-light);
}

.breadcrumb a { color: var(--text-light); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span { margin: 0 8px; }

/* Footer */
.footer {
  background: var(--dark-bg);
  color: var(--white);
  padding: 60px 0 30px;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h4 {
  color: var(--white);
  font-size: 1rem;
  margin-bottom: 16px;
}

.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 8px; }
.footer-col a { color: #94a3b8; }
.footer-col a:hover { color: var(--accent); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 30px;
  text-align: center;
  font-size: 0.875rem;
  color: #94a3b8;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--dark-bg) 100%);
  color: var(--white);
  padding: 80px 0;
  text-align: center;
}

.hero h1 {
  color: var(--white);
  font-size: clamp(2rem, 5vw, 3rem);
  margin-bottom: 16px;
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto 32px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
}

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

.btn-primary:hover {
  background: #4fc3f7;
  transform: translateY(-2px);
  color: var(--dark-bg);
}

.btn-secondary {
  background: rgba(255,255,255,0.1);
  color: var(--white);
  border: 2px solid rgba(255,255,255,0.3);
}

.btn-secondary:hover {
  background: rgba(255,255,255,0.2);
  color: var(--white);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

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

/* Section Styles */
.section {
  padding: 60px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 40px;
}

.section-header h2 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.section-header p {
  color: var(--text-light);
  font-size: 1.1rem;
}

/* Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all 0.3s;
}

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

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--light-bg);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  color: var(--primary);
}

.card-icon svg { width: 24px; height: 24px; }

.card h3 { font-size: 1.125rem; margin-bottom: 8px; }
.card p { color: var(--text-light); font-size: 0.9rem; margin-bottom: 16px; }

/* Article Card */
.article-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all 0.3s;
}

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

.article-card img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.article-card-content { padding: 20px; }

.article-card .category {
  display: inline-block;
  background: var(--light-bg);
  color: var(--primary);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.article-card h3 {
  font-size: 1.125rem;
  margin-bottom: 8px;
  line-height: 1.4;
}

.article-card p {
  color: var(--text-light);
  font-size: 0.875rem;
  margin-bottom: 12px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.8rem;
  color: var(--text-light);
}

/* Stats Bar */
.stats-bar {
  background: var(--light-bg);
  padding: 40px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 24px;
  text-align: center;
}

.stat-item h3 {
  font-size: 2.5rem;
  color: var(--primary);
  margin-bottom: 4px;
}

.stat-item p {
  color: var(--text-light);
  font-weight: 500;
}

/* Filter Tabs */
.filter-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-bottom: 32px;
}

.filter-tab {
  padding: 8px 20px;
  border: 2px solid var(--border);
  border-radius: 30px;
  background: var(--white);
  color: var(--text);
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.filter-tab:hover, .filter-tab.active {
  border-color: var(--primary);
  background: var(--primary);
  color: var(--white);
}

/* Tool Page */
.tool-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}

@media (max-width: 900px) {
  .tool-container { grid-template-columns: 1fr; }
}

.tool-form {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}

.tool-result {
  background: var(--light-bg);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
}

.result-value {
  font-size: 3rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 8px;
}

.result-unit {
  font-size: 1.5rem;
  color: var(--text-light);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.form-group input, .form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.2s;
}

.form-group input:focus, .form-group select:focus {
  outline: none;
  border-color: var(--primary);
}

.form-group .unit {
  display: inline-block;
  margin-left: 8px;
  color: var(--text-light);
  font-size: 0.875rem;
}

/* Explanation Box */
.explanation-box {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-top: 32px;
}

.explanation-box h3 {
  margin-bottom: 16px;
  color: var(--primary);
}

/* Related Links */
.related-links {
  background: var(--light-bg);
  border-radius: var(--radius);
  padding: 24px;
  margin-top: 32px;
}

.related-links h4 {
  margin-bottom: 16px;
  color: var(--dark-bg);
}

.related-links ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.related-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--white);
  border-radius: var(--radius-sm);
  font-weight: 500;
  transition: all 0.2s;
}

.related-links a:hover {
  background: var(--primary);
  color: var(--white);
}

/* FAQ Section */
.faq-section {
  margin-top: 48px;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 16px;
  overflow: hidden;
}

.faq-question {
  background: var(--light-bg);
  padding: 16px 20px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-question:hover { background: #d1e9fc; }

.faq-answer {
  padding: 20px;
  display: none;
}

.faq-item.active .faq-answer { display: block; }
.faq-item.active .faq-icon { transform: rotate(180deg); }

.faq-icon {
  transition: transform 0.2s;
}

/* Contact Form */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
}

@media (max-width: 900px) {
  .contact-grid { grid-template-columns: 1fr; }
}

.contact-form {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}

.contact-form input, .contact-form textarea {
  width: 100%;
  padding: 12px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-family: inherit;
  margin-bottom: 20px;
}

.contact-form textarea { min-height: 150px; resize: vertical; }
.contact-form input:focus, .contact-form textarea:focus {
  outline: none;
  border-color: var(--primary);
}

.contact-info { padding: 20px 0; }

.contact-info h3 { margin-bottom: 24px; }

.contact-info-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 24px;
}

.contact-info-item svg {
  width: 24px;
  height: 24px;
  color: var(--primary);
  flex-shrink: 0;
  margin-top: 4px;
}

/* Legal Pages */
.legal-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

.legal-content h2 {
  font-size: 1.5rem;
  margin: 40px 0 16px;
  color: var(--primary);
}

.legal-content h3 {
  font-size: 1.25rem;
  margin: 24px 0 12px;
}

.legal-content p, .legal-content li {
  margin-bottom: 16px;
  line-height: 1.8;
}

.legal-content ul { padding-left: 24px; }

/* 404 Page */
.error-page {
  min-height: 60vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 60px 20px;
}

.error-page h1 {
  font-size: 6rem;
  color: var(--primary);
  margin-bottom: 16px;
}

.error-page h2 { margin-bottom: 16px; }
.error-page p { color: var(--text-light); margin-bottom: 32px; }

/* Article Page */
.article-header {
  padding: 40px 0;
  background: var(--light-bg);
}

.article-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

.article-content h2 {
  font-size: 1.75rem;
  margin: 48px 0 24px;
  color: var(--dark-bg);
}

.article-content h3 {
  font-size: 1.35rem;
  margin: 32px 0 16px;
}

.article-content p { margin-bottom: 20px; line-height: 1.9; }

.article-content img {
  border-radius: var(--radius);
  margin: 24px 0;
}

.article-content figure {
  margin: 32px 0;
}

.article-content figcaption {
  text-align: center;
  color: var(--text-light);
  font-size: 0.875rem;
  margin-top: 8px;
}

/* Tool Card for Tools Page */
.tool-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  transition: all 0.3s;
}

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

.tool-card-icon {
  width: 64px;
  height: 64px;
  background: var(--light-bg);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  color: var(--primary);
}

.tool-card-icon svg { width: 32px; height: 32px; }

.tool-card h3 { font-size: 1rem; margin-bottom: 8px; }
.tool-card p { color: var(--text-light); font-size: 0.85rem; margin-bottom: 16px; }

/* About Page */
.about-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

.about-content h2 {
  font-size: 1.75rem;
  margin: 48px 0 24px;
  color: var(--dark-bg);
}

.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px;
  margin: 32px 0;
}

.team-member {
  background: var(--light-bg);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
}

.team-member img {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  margin-bottom: 16px;
  object-fit: cover;
}

.team-member h4 { margin-bottom: 4px; }
.team-member p { color: var(--text-light); font-size: 0.9rem; }

/* Utilities */
.text-center { text-align: center; }
.mb-4 { margin-bottom: 32px; }
.mt-4 { margin-top: 32px; }

/* Schema.org hide */
[itemprop="description"] { display: none; }

/* Hidden for filter */
.hidden { display: none !important; }