/* ===============================
   Global Base
   =============================== */
html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  box-sizing: border-box;
  font-family: var(--font-base);
  background-color: var(--color-bg);
  color: var(--color-text);
}

*, *::before, *::after {
  box-sizing: inherit;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ===============================
   Variables
   =============================== */
:root {
  --color-bg: #f6f7fb;
  --color-surface: #ffffff;
  --color-text: #1b1b1b;
  --color-accent: #0055cc;
  --color-border: #d0d7de;
  --color-legend-low: #e0efff;
  --color-legend-high: #002b80;

  --font-base: system-ui, sans-serif;
  --font-size-base: 1rem;
  --line-height-base: 1.5;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;

  --radius-sm: 4px;
  --radius-md: 8px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.1);

  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;

  --breakpoint-sm: 640px;
  --breakpoint-md: 1024px;
}

/* ===============================
   Layout Containers
   =============================== */
.app-header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.app-controls {
  background-color: var(--color-surface);
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.heatmap-area {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-bg);
  padding: var(--spacing-md);
  overflow: auto;
}

.heatmap-legend {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: center;
}

.app-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-sm) var(--spacing-md);
  text-align: center;
  font-size: 0.875rem;
  color: var(--color-text);
}

@media (min-width: 640px) {
  .app-controls {
    justify-content: flex-start;
  }
}

@media (min-width: 1024px) {
  .heatmap-area {
    padding: var(--spacing-lg);
  }
}

.app-footer::after {
  content: "© 2026 Donau2Space.de";
  display: block;
  margin-top: var(--spacing-xs);
  font-size: 0.75rem;
  color: var(--color-text);
}