:root {
  --primary-yellow: #FFD13B;
  --dark: #0D0D0D;
  --bg-light: #F5F5F5;
  --white: #FFFFFF;
  --gray-border: #E5E7EB;
  --text-muted: #6B7280;
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-light);
  color: var(--dark);
  line-height: 1.6;
}

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

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo-link {
  text-decoration: none;
  display: inline-flex;
  align-items: center;
}

.logo-svg {
  height: 38px;
  width: auto;
}

nav a {
  text-decoration: none;
  color: var(--dark);
  font-weight: 500;
  margin-left: 1.5rem;
  font-size: 0.95rem;
  transition: color 0.2s;
}

nav a:hover, nav a.active {
  color: #c49e00;
}

/* Layout Container */
.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 4rem 1.5rem 2.5rem;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}

.hero h1 span {
  background: linear-gradient(180deg, transparent 65%, var(--primary-yellow) 65%);
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 650px;
  margin: 0 auto 2rem;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.85rem 1.8rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 8px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.25s ease;
  border: none;
}

.btn-primary {
  background-color: var(--primary-yellow);
  color: var(--dark);
  box-shadow: 0 4px 14px rgba(255, 209, 59, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(255, 209, 59, 0.6);
}

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

.btn-secondary:hover {
  opacity: 0.9;
}

/* Cards & Content */
.card {
  background: var(--white);
  border-radius: 12px;
  padding: 2rem;
  border: 1px solid var(--gray-border);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.04);
  margin-bottom: 2.5rem;
}

.card-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

/* Abrechnungs-Tabelle */
.invoice-header {
  border-bottom: 2px solid var(--dark);
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.invoice-badge {
  background: #FFF8E1;
  border: 1px solid var(--primary-yellow);
  padding: 0.35rem 0.75rem;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
}

.table-responsive {
  overflow-x: auto;
}

.invoice-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

.invoice-table th, .invoice-table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--gray-border);
}

.invoice-table th {
  background-color: #fafafa;
  font-weight: 600;
  color: var(--dark);
}

.invoice-table tr:last-child td {
  border-bottom: none;
  font-weight: 700;
  background-color: #fafafa;
}

.tag-solar {
  color: #b58900;
  font-weight: 600;
}

.tag-grid {
  color: #4b5563;
}

/* Ratio Bar */
.ratio-bar {
  height: 8px;
  background-color: #e5e7eb;
  border-radius: 4px;
  overflow: hidden;
  display: flex;
  margin-top: 4px;
  min-width: 90px;
}

.ratio-solar {
  background-color: var(--primary-yellow);
}

.ratio-grid {
  background-color: var(--dark);
}

/* Formulare */
.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.4rem;
  font-weight: 500;
  font-size: 0.9rem;
}

.form-group input, .form-group textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--gray-border);
  border-radius: 6px;
  font-family: inherit;
  font-size: 0.95rem;
}

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

/* Footer */
footer {
  background: var(--white);
  border-top: 1px solid var(--gray-border);
  padding: 2.5rem 1.5rem;
  margin-top: 4rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-content {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  margin-left: 1rem;
}

.footer-links a:hover {
  color: var(--dark);
}