:root {
  --bg-main: #0b0f19;
  --bg-card: #131b2e;
  --bg-card-hover: #1a253e;
  --bg-header: #0e1526;
  --border-color: #212e4a;
  --border-subtle: #192338;
  --color-primary: #f97316;
  --color-primary-hover: #ea580c;
  --color-secondary: #0ea5e9;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-text: #f1f5f9;
  --color-text-muted: #94a3b8;
  --color-text-dim: #64748b;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--color-text);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: 1380px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header & Nav */
.site-header {
  background-color: var(--bg-header);
  border-bottom: 1px solid var(--border-color);
  padding: 0.85rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--color-text);
  font-weight: 700;
  font-size: 1.2rem;
}

.brand-badge {
  background: linear-gradient(135deg, #f97316, #ef4444);
  color: #fff;
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 1.25rem;
  align-items: center;
}

.nav-menu a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s;
  padding: 0.35rem 0.6rem;
  border-radius: var(--radius-sm);
}

.nav-menu a:hover, .nav-menu a.active {
  color: var(--color-text);
  background: var(--bg-card-hover);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s ease;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #fff;
}
.btn-primary:hover {
  background-color: var(--color-primary-hover);
}

.btn-secondary {
  background-color: var(--bg-card);
  color: var(--color-text);
  border-color: var(--border-color);
}
.btn-secondary:hover {
  background-color: var(--bg-card-hover);
  border-color: var(--color-primary);
}

.btn-sm {
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
}

/* Cards & Grid */
.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  box-shadow: var(--shadow);
  transition: transform 0.2s, border-color 0.2s;
}

.card:hover {
  border-color: #3b4e78;
}

.card-header-small {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.card-value {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.1;
  color: #fff;
}

.card-unit {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-left: 0.2rem;
}

.card-subtext {
  font-size: 0.8rem;
  color: var(--color-text-dim);
  margin-top: 0.5rem;
}

/* Puffer Visualisierung */
.puffer-container {
  display: flex;
  gap: 1.5rem;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin: 1.5rem 0;
}

.puffer-tank {
  width: 140px;
  height: 240px;
  border: 3px solid #3b4e78;
  border-radius: 40px / 20px;
  position: relative;
  background: #0f172a;
  overflow: hidden;
  box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.8);
  display: flex;
  flex-direction: column;
}

.puffer-layer {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.1rem;
  color: #fff;
  text-shadow: 0 1px 3px rgba(0,0,0,0.8);
  transition: background 0.5s ease;
  position: relative;
  border-bottom: 1px dashed rgba(255,255,255,0.15);
}
.puffer-layer:last-child { border-bottom: none; }

.puffer-layer-label {
  position: absolute;
  left: 8px;
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  opacity: 0.8;
}

/* Form Styles */
.form-card {
  max-width: 440px;
  margin: 3rem auto;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
  box-shadow: var(--shadow);
}

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

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.form-control {
  width: 100%;
  padding: 0.65rem 0.85rem;
  background: #0b1120;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: #fff;
  font-size: 0.95rem;
  transition: border-color 0.2s;
}

.form-control:focus {
  outline: none;
  border-color: var(--color-primary);
}

/* Alerts */
.alert {
  padding: 0.85rem 1.25rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
  font-size: 0.9rem;
}
.alert-success { background: rgba(16, 185, 129, 0.15); border: 1px solid var(--color-success); color: #34d399; }
.alert-danger { background: rgba(239, 68, 68, 0.15); border: 1px solid var(--color-danger); color: #f87171; }
.alert-warning { background: rgba(245, 158, 11, 0.15); border: 1px solid var(--color-warning); color: #fbbf24; }

/* Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

.data-table th, .data-table td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.9rem;
}

.data-table th {
  background: var(--bg-card-hover);
  color: var(--color-text-muted);
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
}

/* Footer */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-color);
  padding: 1.5rem 0;
  font-size: 0.85rem;
  color: var(--color-text-dim);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

/* Pulse status */
.status-dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--color-success);
  margin-right: 6px;
  box-shadow: 0 0 8px var(--color-success);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

@media (max-width: 768px) {
  .nav-container { flex-direction: column; align-items: flex-start; }
  .puffer-container { flex-direction: column; }
  .nav-menu { flex-wrap: wrap; }
}