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

html, body {
  height: 100%;
  overflow: hidden;
}

body {
  background: #0f0f0f;
  color: #e0e0e0;
  font-family: "Inter", system-ui, sans-serif;
  padding: 1.5rem;
}

#app {
  max-width: 900px;
  margin: 0 auto;
  height: 100%;
  display: flex;
  flex-direction: column;
}

header {
  margin-bottom: 1rem;
  flex-shrink: 0;
}

h1 {
  font-size: 1rem;
  font-weight: 400;
  color: #888;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

#current-price {
  font-size: 2.5rem;
  font-weight: 600;
  margin: 0.25rem 0;
}

#price-change {
  font-size: 0.9rem;
  color: #888;
}

#price-change.up {
  color: #4caf50;
}

#price-change.down {
  color: #f44336;
}

#span-selector {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
  flex-shrink: 0;
}

.span-btn {
  background: transparent;
  border: 1px solid #333;
  color: #888;
  padding: 0.3rem 0.75rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.8rem;
  transition: all 0.15s;
}

.span-btn:hover {
  border-color: #666;
  color: #ccc;
}

.span-btn.active {
  border-color: #c0c0c0;
  color: #c0c0c0;
  background: #1e1e1e;
}

#chart-container {
  flex: 1;
  min-height: 0;
}

#chart-container svg {
  width: 100%;
  height: 100%;
}

.area-path {
  fill: url(#areaGradient);
  stroke: none;
}

.line-path {
  fill: none;
  stroke: #c0c0c0;
  stroke-width: 1.5px;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.axis text {
  fill: #555;
  font-size: 0.7rem;
}

.axis line,
.axis path {
  stroke: #222;
}

.tooltip {
  position: fixed;
  background: #1e1e1e;
  border: 1px solid #333;
  border-radius: 4px;
  padding: 0.5rem 0.75rem;
  font-size: 0.8rem;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.1s;
}

footer {
  margin-top: 0.75rem;
  font-size: 0.65rem;
  color: #444;
  text-align: center;
  flex-shrink: 0;
}