/* Reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary-color: #B2C8B2;
  --dark-color: #2E8B57;
  --text-color: #333;
  --bg-color: #fff;
  --transition: all 0.3s ease;
}

html,
body {
  min-height: 100%;
  height: 100%;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background 0.3s, color 0.3s;
}

/* Header */
header {
  background: var(--bg-color);
  border-bottom: 4px solid #222;
  width: 100vw;
}

.header-container {
  width: 100%;
  padding: 15px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

img.logo {
  max-width: 300px;
  width: 100%;
  height: auto;
  margin: 0 auto 15px;
  display: block;
}

/* Navigation */
nav {
  border-top: 3px solid var(--primary-color);
  border-bottom: 3px solid var(--primary-color);
  background: var(--dark-color);
  width: 100vw;
  padding: 15px 20px;
  position: relative;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 2.5rem;
  margin: 0 auto;
  padding: 0;
  justify-content: flex-start;
  align-items: center;
}

nav ul li a {
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 1.1rem;
  padding: 10px 15px;
  transition: var(--transition);
}

nav ul li a:hover,
nav ul li a:focus {
  color: var(--primary-color);
  outline: none;
}

/* Hamburger (mobile only) */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  position: absolute;
  left: 20px;
  top: 1.75rem;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  cursor: pointer;
  z-index: 1001;
}

.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
  display: block;
  background: #fff;
  height: 4px;
  width: 28px;
  border-radius: 3px;
  position: absolute;
  transition: 0.3s cubic-bezier(.4, 0, .2, 1);
}

.nav-toggle span {
  top: 18px;
}

.nav-toggle span::before {
  top: -10px;
  content: '';
}

.nav-toggle span::after {
  top: 10px;
  content: '';
}

.nav-toggle.active span {
  background: transparent;
}

.nav-toggle.active span::before {
  transform: rotate(45deg);
  top: 0;
  background: #fff;
}

.nav-toggle.active span::after {
  transform: rotate(-45deg);
  top: 0;
  background: #fff;
}

/* Mobile menu */
@media (max-width: 900px) {
  header {
    background: var(--dark-color);
    border-bottom: none;
  }

  .header-container {
    padding: 10px 15px;
    background: var(--bg-color);
  }

  nav {
    background: var(--dark-color);
    padding: 30px;
  }

  nav ul {
    flex-direction: column;
    position: fixed;
    top: 0;
    right: -100vw;
    width: 80vw;
    height: 100vh;
    background: var(--dark-color);
    justify-content: flex-start;
    align-items: flex-start;
    padding: 80px 24px 24px;
    gap: 24px;
    box-shadow: -4px 0 24px rgba(0, 0, 0, 0.08);
    z-index: 1000;
    transition: right 0.3s cubic-bezier(.4, 0, .2, 1);
    overflow-y: auto;
  }

  nav ul.active {
    right: 0;
  }

  nav ul li {
    width: 100%;
    text-align: left;
    border-bottom: 1px solid #222;
    margin-bottom: 10px;
  }

  nav ul li:last-child {
    border-bottom: none;
    margin-bottom: 0;
  }

  nav ul li a {
    padding: 15px 0;
    font-size: 1.2rem;
    color: #fff;
    display: block;
    width: 100%;
    transition: color 0.2s;
  }

  nav ul li a:hover,
  nav ul li a:focus {
    color: var(--primary-color);
  }

  .nav-toggle {
    display: block;
  }

  img.logo {
    max-width: 50%;
  }
}

/* Desktop menu */
@media (min-width: 901px) {
  .nav-toggle {
    display: none !important;
  }

  nav ul {
    position: static;
    flex-direction: row;
    height: auto;
    width: auto;
    background: transparent;
    box-shadow: none;
    padding: 0;
    gap: 2.5rem;
    justify-content: center;
    align-items: center;
    margin: 0 auto;
  }

  nav ul li {
    border: none;
    margin: 0 10px 0 0;
    text-align: center;
  }

  nav ul li:last-child {
    margin-right: 0;
  }

  nav ul li a {
    color: #fff;
    font-size: 1rem;
    padding: 10px 16px;
    transition: color 0.2s;
  }

  nav ul li a:hover,
  nav ul li a:focus {
    color: var(--primary-color);
  }
}

/* Hero image */
.hero-image {
  width: 100vw;
  height: 450px;
  background: url('obrazy/biomass.webp') center/cover no-repeat;
  background-attachment: fixed;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  margin-top: 0;
  will-change: background-position;
}

.hero-image::before {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.45);
  z-index: 1;
}

.hero-text {
  position: relative;
  z-index: 2;
  color: #fff;
  text-align: center;
  padding: 20px;
  width: 100%;
  max-width: 1000px;
}

.hero-text h1 {
  font-size: 2.8rem;
  margin-bottom: 15px;
}

.hero-text p {
  font-size: 1.4rem;
}

@media (max-width: 768px) {
  .hero-image {
    height: 350px;
    background-attachment: scroll;
  }

  .hero-text h1 {
    font-size: 2rem;
  }

  .hero-text p {
    font-size: 1.2rem;
  }

  img.logo {
    max-width: 45%;
  }
}

@media (max-width: 600px) {
  img.logo {
    max-width: 40%;
  }
}

@media (max-width: 480px) {
  .hero-image {
    height: 300px;
    background-attachment: scroll;
  }

  .hero-text h1 {
    font-size: 1.8rem;
  }

  .hero-text p {
    font-size: 1rem;
  }

  img.logo {
    max-width: 35%;
  }
}

/* Additional images */
.additional-images {
  display: flex;
  justify-content: center;
  gap: 15rem;
  width: 100vw;
  margin: 15px 0;
  padding: 0;
  flex-wrap: wrap;
}

.image-item {
  flex: 1 1 200px;
  text-align: center;
  max-width: 9rem;
  transition: transform 0.3s ease;
}

.image-item img {
  width: 100%;
  max-width: 9rem;
  height: auto;
  border-radius: 8px;
  margin-bottom: 15px;
}

.image-item p {
  font-size: 0.7rem;
  color: black;
  margin-bottom: 25px;
}

/* Why biomass section */
.why-biomass {
  width: 100vw;
  margin: 40px 0;
  padding: 40px 15px;
  text-align: center;
}

.why-biomass h2 {
  font-size: 2.2rem;
  color: black;
  margin-bottom: 30px;
}

.why-biomass-features {
  display: flex;
  justify-content: center;
  gap: 30px;
  flex-wrap: wrap;
  width: 100%;
  padding: 0 15px;
}

.feature {
  flex: 1 1 300px;
  padding: 25px 20px;
  text-align: center;
  color: black;
  max-width: 350px;
  transition: transform 0.3s ease;
}

.feature:hover {
  transform: translateY(-10px);
}

.feature-icon {
  font-size: 3rem;
  color: var(--dark-color);
  margin-bottom: 15px;
  display: inline-block;
}

.feature h3 {
  font-size: 1.4rem;
  margin-bottom: 12px;
}

.feature p {
  font-size: 1.1rem;
  color: black;
}

/* Footer menu and contact */
.footer-menu-contact {
  border-top: 3px solid var(--primary-color);
  border-bottom: 3px solid var(--primary-color);
  background: var(--dark-color);
  color: #fff;
  padding: 10px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  width: 100vw;
}

.footer-menu,
.footer-contact {
  flex: 1 1 300px;
  margin: 20px 15px;
  text-align: center;
}

.footer-menu h3,
.footer-contact h3 {
  font-size: 1.5rem;
  color: white;
  margin-bottom: 15px;
}

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

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

.footer-menu ul li a {
  color: #fff;
  text-decoration: none;
  font-size: 1.1rem;
  transition: var(--transition);
}

.footer-menu ul li a:hover,
.footer-menu ul li a:focus {
  color: var(--primary-color);
}

.footer-contact p {
  font-size: 1.1rem;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
  justify-content: center;
}

.footer-contact i {
  color: var(--primary-color);
  font-size: 1.3rem;
}

.site-footer {
  background: var(--dark-color);
  color: white;
  text-align: center;
  padding: 20px 15px;
  font-size: 1rem;
  border-top: 3px solid var(--primary-color);
  width: 100vw;
}

.site-footer a {
  color: whitesmoke;
}

/* Responsive tweaks */
@media (max-width: 768px) {
  .header-container {
    padding: 10px 15px;
  }

  img.logo {
    max-width: 45%;
  }

  .additional-images {
    gap: 1.4rem;
    padding: 0 10px;
  }

  .image-item {
    flex: 1 1 100%;
    max-width: 100%;
  }

  .why-biomass {
    padding: 30px 10px;
  }

  .why-biomass h2 {
    font-size: 1.8rem;
  }

  .why-biomass-features {
    flex-direction: column;
    gap: 20px;
    padding: 0 10px;
  }

  .feature {
    max-width: 100%;
    padding: 20px 15px;
  }

  .feature-icon {
    font-size: 2.8rem;
  }

  .feature h3 {
    font-size: 1.3rem;
  }

  .feature p {
    font-size: 1rem;
  }

  .footer-menu-contact {
    flex-direction: column;
    align-items: center;
    padding: 30px 10px;
  }

  .footer-menu,
  .footer-contact {
    margin: 15px 0;
  }
}

@media (max-width: 600px) {
  img.logo {
    max-width: 40%;
  }
}

@media (max-width: 480px) {
  .hero-image {
    height: 300px;
  }

  .hero-text h1 {
    font-size: 1.8rem;
  }

  .hero-text p {
    font-size: 1rem;
  }

  img.logo {
    max-width: 35%;
  }

  .why-biomass h2 {
    font-size: 1.6rem;
  }

  .feature-icon {
    font-size: 2.5rem;
  }

  .feature h3 {
    font-size: 1.2rem;
  }

  .footer-menu h3,
  .footer-contact h3 {
    font-size: 1.3rem;
  }

  .footer-menu ul li a,
  .footer-contact p {
    font-size: 1rem;
  }
}

/* Contact section */
.contact-section {
  max-width: 60rem;
  margin: 2.5rem auto;
  padding: 0 1rem;
  color: var(--text-color);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.contact-section h2 {
  color: black;
  font-weight: 700;
  margin-bottom: 1.5rem;
  font-size: 2rem;
  letter-spacing: 0.01em;
  text-align: center;
}

.contact-container {
  display: flex;
  gap: 10rem;
  align-items: flex-start;
  justify-content: center;
}

.contact-form,
.contact-info-block {
  flex: 1 1 320px;
  max-width: 32rem;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.contact-form h3,
.contact-info-block h3 {
  width: 100%;
  text-align: left;
  color: var(--dark-color);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.contact-info-block ul {
  list-style: none;
  padding: 0;
  margin: 0 0 1.5rem;
  width: 100%;
}

.contact-info-block li {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  font-size: 1.05rem;
  margin-bottom: 0.6rem;
  color: var(--text-color);
  justify-content: flex-start;
}

.contact-info-block i {
  color: var(--primary-color);
  font-size: 1.2rem;
  min-width: 1.4rem;
  text-align: center;
}

.contact-info-block a {
  color: var(--dark-color);
  text-decoration: underline;
  font-weight: 500;
}

.contact-persons .contact-person {
  margin-bottom: 3.5rem;
}

.contact-persons h3 {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--dark-color);
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.03rem;
  margin-top: 1.2rem;
  justify-content: flex-start;
}

.contact-persons p {
  margin: 0 0 0.4rem 2rem;
  color: var(--text-color);
  font-size: 0.98rem;
  text-align: left;
}

.contact-form form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  width: 100%;
}

.contact-form label {
  font-weight: 600;
  font-size: 1rem;
  color: var(--dark-color);
  margin-bottom: 0.2rem;
  text-align: left;
  width: 100%;
}

.contact-form input[type="text"],
.contact-form input[type="email"],
.contact-form textarea {
  padding: 0.625rem 0.75rem;
  font-size: 1rem;
  border: 1.5px solid var(--primary-color);
  border-radius: 0.5rem;
  color: var(--text-color);
  background: var(--bg-color);
  transition: border-color 0.2s, box-shadow 0.2s;
  box-shadow: none;
  outline: none;
  resize: vertical;
  width: 100%;
}

.contact-form input[type="text"]:focus,
.contact-form input[type="email"]:focus,
.contact-form textarea:focus {
  border-color: var(--dark-color);
  box-shadow: 0 2px 8px rgba(46, 139, 87, 0.10);
}

.contact-form button {
  width: 10rem;
  max-width: 100%;
  padding: 0.75rem 0;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--bg-color);
  background: var(--dark-color);
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  align-self: flex-start;
  box-shadow: 0 2px 8px rgba(46, 139, 87, 0.08);
  transition: background 0.2s, color 0.2s, transform 0.1s, box-shadow 0.2s;
  letter-spacing: 0.02em;
}

.contact-form button:hover,
.contact-form button:focus {
  background: var(--primary-color);
  color: var(--dark-color);
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 4px 16px rgba(178, 200, 178, 0.16);
  outline: none;
}

@media (max-width: 700px) {
  .contact-container {
    flex-direction: column;
    align-items: center;
    gap: 2.5rem;
    width: 100%;
  }

  .contact-form,
  .contact-info-block {
    max-width: 100%;
    width: 100%;
    align-items: center;
    text-align: center;
  }

  .contact-form h3,
  .contact-info-block h3 {
    text-align: center;
    width: 100%;
  }

  .contact-info-block ul {
    display: inline-block;
    text-align: center;
    padding: 0;
    margin: 0 auto 1.5rem;
    width: auto;
  }

  .contact-info-block li {
    justify-content: center !important;
  }

  .contact-persons h3,
  .contact-persons p {
    justify-content: center !important;
    text-align: center;
    margin-left: 0;
  }

  .contact-form form {
    align-items: center;
    width: 100%;
  }

  .contact-form label,
  .contact-form input,
  .contact-form textarea {
    text-align: center;
    width: 100%;
  }

  .contact-form button {
    width: auto;
    min-width: 140px;
    max-width: 300px;
    padding-left: 2rem;
    padding-right: 2rem;
    align-self: center;
    margin-left: auto;
    margin-right: auto;
    display: block;
  }
}

/* About section */
.about-section {
  max-width: 60rem;
  margin: 3rem auto 2rem;
  padding: 0 1rem;
  color: var(--text-color);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.about-section h2 {
  text-align: center;
  color: black;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 2rem;
  letter-spacing: 0.01em;
}

.about-container {
  display: flex;
  gap: 3rem;
  justify-content: space-between;
  align-items: flex-start;
}

.about-mission,
.about-description {
  flex: 1 1 300px;
  background: none;
  border-radius: 0.5rem;
  padding: 0;
}

.about-mission h3,
.about-description h3 {
  color: var(--dark-color);
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.about-mission i,
.about-description i {
  color: var(--primary-color);
  font-size: 1.3rem;
}

.about-mission p,
.about-description p {
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 1.1rem;
  color: var(--text-color);
}

@media (max-width: 900px) {
  .about-container {
    gap: 1.5rem;
  }
}

@media (max-width: 700px) {
  .about-container {
    flex-direction: column;
    align-items: center;
    gap: 2rem;
  }

  .about-mission,
  .about-description {
    width: 100%;
    max-width: 100%;
    text-align: center;
    padding: 0;
  }

  .about-mission h3,
  .about-description h3 {
    justify-content: center;
    text-align: center;
  }

  .about-mission p,
  .about-description p {
    text-align: center;
  }
}

/* Biomass section */
.biomass-section {
  max-width: 60rem;
  margin: 3rem auto 2rem;
  padding: 0 1rem;
  color: var(--text-color);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.biomass-section h2 {
  text-align: center;
  color: black;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 2.5rem;
  letter-spacing: 0.01em;
}

.biomass-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 3rem;
  justify-content: center;
  align-items: stretch;
}

.biomass-card {
  background: var(--bg-color);
  border-radius: 0.5rem;
  padding: 1.5rem 1.2rem 1.2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  flex: 1 1 260px;
  max-width: 300px;
  min-width: 220px;
  transition: transform 0.2s;
}

.biomass-card:hover {
  transform: translateY(-0.7rem);
}

.biomass-card img {
  width: 100%;
  max-width: 180px;
  height: 110px;
  object-fit: cover;
  border-radius: 0.3rem;
  margin-bottom: 1rem;
  background: #eee;
}

.biomass-card h3 {
  color: var(--dark-color);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.7rem;
  text-align: center;
}

.biomass-card ul {
  padding: 0;
  margin: 0;
  list-style: none;
  width: 100%;
}

.biomass-card ul li {
  padding-left: 1.1em;
  position: relative;
  margin-bottom: 0.4em;
  font-size: 1rem;
}

.biomass-card ul li:before {
  content: "•";
  color: var(--primary-color);
  position: absolute;
  left: 0;
}

@media (max-width: 900px) {
  .biomass-grid {
    gap: 2rem;
  }
}

@media (max-width: 700px) {
  .biomass-section h2 {
    font-size: 1.4rem;
    margin-bottom: 1.2rem;
  }

  .biomass-grid {
    flex-direction: column;
    gap: 2rem;
    align-items: center;
  }

  .biomass-card {
    max-width: 98vw;
    width: 100%;
    min-width: 0;
    padding: 1rem 0.5rem;
  }

  .biomass-card img {
    max-width: 90vw;
    height: 100px;
  }

  .biomass-card ul {
    text-align: center;
  }
}

/* Guide section */
.guide-section {
  max-width: 60rem;
  margin: 3rem auto 6rem;
  padding: 0 1rem;
  color: var(--text-color);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.guide-section h2 {
  text-align: center;
  color: black;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 2.5rem;
  letter-spacing: 0.01em;
}

.guide-block {
  margin-bottom: 2.5rem;
}

.guide-block h3 {
  color: var(--dark-color);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.7rem;
}

.guide-block p,
.guide-block ul {
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 0.4rem;
  color: var(--text-color);
}

.guide-block ul {
  padding-left: 1.2em;
  margin: 0.5rem 0 0;
}

.guide-block ul li {
  margin-bottom: 0.3em;
  list-style: disc;
}

@media (max-width: 700px) {
  .guide-section h2 {
    font-size: 1.4rem;
    margin-bottom: 1.2rem;
  }

  .guide-block {
    margin-bottom: 1.7rem;
  }

  .guide-block h3 {
    font-size: 1rem;
  }

  .guide-block p,
  .guide-block ul {
    font-size: 0.98rem;
  }
}

/* Reveal on scroll */
.reveal-on-scroll {
  opacity: 0;
  transform: translateY(2rem);
  transition: opacity 0.7s cubic-bezier(.4, 0, .2, 1), transform 0.7s cubic-bezier(.4, 0, .2, 1);
  will-change: opacity, transform;
}

.revealed {
  opacity: 1 !important;
  transform: none;
}

/* Back to top */
.back-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: var(--dark-color);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  font-size: 1.5rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s, transform 0.3s;
  z-index: 1000;
}

.back-to-top:hover {
  transform: translateY(-5px);
  background: var(--primary-color);
  color: var(--dark-color);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}