/* === Design Tokens === */
:root {
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Consolas', monospace;

  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);

  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-6:  1.5rem;
  --space-8:  2rem;

  --color-bg:           #0d1117;
  --color-surface:      #161b22;
  --color-surface-2:    #1c2129;
  --color-border:       #30363d;
  --color-text:         #e6edf3;
  --color-text-muted:   #8b949e;
  --color-text-faint:   #484f58;
  --color-primary:      #58a6ff;
  --color-accent:       #3fb950;
  --color-oil:          #d29922;
  --color-oil-light:    #e3b341;
  --color-oil-area:     rgba(210, 153, 34, 0.12);
  --color-grid:         rgba(48, 54, 61, 0.5);
  --color-annotation:   #f78166;

  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;

  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);

  --transition-fast: 120ms ease-out;
  --transition-normal: 200ms ease-out;
}

/* === Reset & Base === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  min-height: 100dvh;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* === Chart Container === */
#chart-container {
  flex: 1;
  position: relative;
  width: 100%;
  padding: var(--space-6) var(--space-4) var(--space-4);
  display: flex;
  flex-direction: column;
}

/* === SVG Chart === */
#chart-container svg {
  width: 100%;
  flex: 1;
}

.chart-title {
  fill: var(--color-text);
  font-family: var(--font-body);
  font-weight: 700;
}

.chart-subtitle {
  fill: var(--color-text-muted);
  font-family: var(--font-body);
  font-weight: 400;
}

/* Axes */
.x-axis text,
.y-axis text {
  fill: var(--color-text-muted);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-variant-numeric: tabular-nums lining-nums;
}

.x-axis line,
.x-axis path,
.y-axis line,
.y-axis path {
  stroke: var(--color-border);
}

.y-axis .tick line {
  stroke: var(--color-grid);
  stroke-dasharray: 2, 3;
}

/* Price line & area */
.price-area {
  fill: var(--color-oil-area);
}

.price-line {
  fill: none;
  stroke: var(--color-oil);
  stroke-width: 2;
  stroke-linejoin: round;
  stroke-linecap: round;
}

/* Crosshair */
.crosshair-line {
  stroke: var(--color-text-faint);
  stroke-width: 1;
  stroke-dasharray: 4, 3;
  pointer-events: none;
}

.crosshair-dot {
  fill: var(--color-oil-light);
  stroke: var(--color-bg);
  stroke-width: 2;
  pointer-events: none;
}

/* === Tooltip === */
.tooltip {
  position: absolute;
  display: none;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-2) var(--space-3);
  pointer-events: none;
  box-shadow: var(--shadow-md);
  z-index: 100;
  font-variant-numeric: tabular-nums lining-nums;
  white-space: nowrap;
}

.tooltip-date {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: 2px;
}

.tooltip-price {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-oil-light);
}

/* === Event Annotations === */
.event-marker {
  cursor: pointer;
  transition: transform var(--transition-fast);
}

.event-marker:hover .event-marker-circle {
  r: 7;
}

.event-marker-circle {
  fill: var(--color-annotation);
  stroke: var(--color-bg);
  stroke-width: 2;
  transition: r var(--transition-fast);
}

.event-marker-pulse {
  fill: var(--color-annotation);
  opacity: 0;
  animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0; r: 5; }
  50% { opacity: 0.2; r: 12; }
}

.event-line {
  stroke: var(--color-annotation);
  stroke-width: 1;
  stroke-dasharray: 2, 2;
  opacity: 0.4;
}

/* === Event Tooltip === */
.event-tooltip {
  position: absolute;
  display: none;
  background: var(--color-surface);
  border: 1px solid var(--color-annotation);
  border-radius: var(--radius-lg);
  padding: var(--space-3) var(--space-4);
  max-width: 320px;
  box-shadow: var(--shadow-lg);
  z-index: 200;
  pointer-events: none;
}

.event-tooltip-date {
  font-size: var(--text-xs);
  color: var(--color-annotation);
  font-weight: 600;
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.event-tooltip-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 4px;
  line-height: 1.3;
}

.event-tooltip-desc {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* === Footer === */
footer {
  text-align: center;
  padding: var(--space-2) var(--space-4);
  border-top: 1px solid var(--color-border);
}

footer a {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  text-decoration: none;
  transition: color var(--transition-normal);
}

footer a:hover {
  color: var(--color-text-muted);
}

/* === Responsive === */
@media (max-width: 768px) {
  #chart-container {
    padding: var(--space-3) var(--space-2) var(--space-2);
  }

  .event-tooltip {
    max-width: 260px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}