:root {
  --bg-light: #f7f7f7;
  --text-dark: #2a2a2a;
  --accent: #c29945;
  --font-sans: 'Helvetica Neue', Arial, sans-serif;
}

body {
  font-family: var(--font-sans);
  margin: 0;
  background: var(--bg-light);
  color: var(--text-dark);
  transition: background 0.3s, color 0.3s;
}

.header {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.95);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  z-index: 1000;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.header h1 {
  font-size: 1.2rem;
  margin-left: 0.5rem;
}

nav a {
  margin: 0 1rem;
  color: var(--text-dark);
  text-decoration: none;
  font-weight: 500;
}

nav a:hover {
  color: var(--accent);
}

#menu-toggle, #theme-toggle {
  background: none;
  border: none;
  font-size: 1.5rem;
  margin-left: 1rem;
  cursor: pointer;
}

#navbar.active {
  display: block;
}

#hero {
  background: url('https://source.unsplash.com/1600x800/?green,energy') center/cover no-repeat;
  height: 80vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  color: #fff;
}

#hero h1 {
  font-size: 3rem;
  margin: 0;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

#hero p {
  font-size: 1.2rem;
  margin-top: 1rem;
}

section {
  padding: 4rem 2rem;
  text-align: center;
}

.content-block {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  align-items: center;
  justify-content: center;
}

.content-block img {
  max-width: 400px;
  border-radius: 8px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.card {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.05);
  transition: transform 0.3s;
}

.card:hover {
  transform: translateY(-5px);
}

.card img {
  max-width: 100%;
  border-radius: 6px;
}

.button {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  border-radius: 5px;
  transition: background 0.3s;
}

.button:hover {
  background: #a67c2d;
}

footer {
  background: #222;
  color: #fff;
  text-align: center;
  padding: 1rem;
}

#back-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: none;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  font-size: 1.2rem;
  cursor: pointer;
  box-shadow: 0 2px 5px rgba(0,0,0,0.3);
}

/* Dark theme */
.dark-theme {
  --bg-light: #1e1e1e;
  --text-dark: #f0f0f0;
  background: var(--bg-light);
  color: var(--text-dark);
}

.dark-theme .header {
  background: rgba(34, 34, 34, 0.95);
}

.dark-theme .card {
  background: #2c2c2c;
}

.dark-theme footer {
  background: #000;
}

/* Contact Form */
#contact form {
  max-width: 600px;
  margin: 20px auto;
  padding: 25px;
  background-color: #f9f9f9; /* light neutral background */
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  display: flex;
  flex-direction: column;
  gap: 15px;
}

#contact form label {
  font-weight: 600;
  margin-bottom: 5px;
  color: #333;
}

#contact form input,
#contact form textarea {
  padding: 12px 15px;
  border: 1px solid #ccc;
  border-radius: 8px;
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.3s, box-shadow 0.3s;
}

#contact form input:focus,
#contact form textarea:focus {
  border-color: #4CAF50; /* green accent */
  box-shadow: 0 0 8px rgba(76, 175, 80, 0.3);
  outline: none;
}

#contact form button.button {
  background-color: #4CAF50;
  color: #fff;
  font-weight: 600;
  padding: 14px;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-size: 1rem;
  transition: background-color 0.3s, transform 0.2s;
}

#contact form button.button:hover {
  background-color: #45a049;
  transform: translateY(-2px);
}

/* Success and Error Messages */
.message {
  max-width: 600px;
  margin: 15px auto;
  padding: 15px 20px;
  border-radius: 10px;
  font-weight: 500;
  font-size: 1rem;
  text-align: center;
}

.message.success {
  background-color: #e6f7ea;  /* light green */
  border: 1px solid #4CAF50;
  color: #2e7d32;
}

.message.error {
  background-color: #fdecea; /* light red/pink */
  border: 1px solid #f44336;
  color: #c62828;
}