/*
 * Responsive dark-themed styling for the ultrasound ECG monitor.
 * Provides a modern, high-contrast look reminiscent of clinical monitors
 * and adapts gracefully to phones, tablets and desktop screens.
 */

:root {
    --bg: #020617;
    --bg-elevated: #061124;
    --card-bg: #0b1c35;
    --border: #1e293b;
    --accent: #2dd4bf;
    --accent-soft: rgba(45, 212, 191, 0.15);
    --text: #f1f5f9;
    --muted: #94a3b8;
    --danger: #f87171;
    --font-main: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

html, body {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    background: radial-gradient(circle at top, #0f172a 0%, #010914 70%, #000 100%);
    color: var(--text);
    font-family: var(--font-main);
}

.app-header {
    text-align: center;
    padding: 1rem 0.5rem;
    border-bottom: 1px solid var(--border);
    background: transparent;
    position: sticky;
    top: 0;
    z-index: 10;
}
.app-header h1 {
    margin: 0;
    font-size: 1.4rem;
    font-weight: 600;
    letter-spacing: 0.03em;
}

.app-main {
    padding: 1rem 0.75rem 1.5rem;
    max-width: 960px;
    margin: 0 auto;
}

/* Controls */
.controls-row {
    display: flex;
    gap: 0.8rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
    justify-content: center;
}
.controls-row button {
    flex: 1 1 auto;
    min-width: 120px;
    padding: 0.6rem 1rem;
    font-size: 1rem;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: var(--bg-elevated);
    color: var(--text);
    cursor: pointer;
    transition: background 0.18s ease, transform 0.1s ease, box-shadow 0.18s ease;
}
.controls-row button:hover:not(:disabled) {
    background: var(--accent-soft);
    box-shadow: 0 0 12px var(--accent-soft);
    transform: translateY(-1px);
}
.controls-row button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Settings */
.settings {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}
.setting-group {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 0.8rem;
    padding: 0.75rem 0.9rem;
}
.setting-group label {
    display: block;
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 0.3rem;
}
.setting-group .input-row {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 0.75rem;
    flex-wrap: nowrap;
}
.setting-group input[type="number"] {
    width: 100%;
    max-width: 8rem;
    min-width: 4rem;
    padding: 0.5rem 0.75rem;
    border-radius: 0.5rem;
    border: 1px solid var(--border);
    background: var(--bg);
    color: var(--text);
    font-size: 0.9rem;
    box-sizing: border-box;
}
.setting-group .dash {
    color: var(--muted);
    font-size: 1rem;
    flex-shrink: 0;
    padding: 0 0.25rem;
}
.setting-group .sub {
    color: var(--muted);
    font-size: 0.75rem;
}

/* Canvas card */
.canvas-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 0.9rem;
    padding: 0.75rem 0.9rem 1rem;
    margin-bottom: 1rem;
    box-shadow:
        0 18px 40px rgba(0, 0, 0, 0.7),
        0 0 0 1px var(--border);
}
.canvas-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
    color: var(--muted);
}
.grid-info {
    font-size: 0.8rem;
    color: rgba(148, 163, 184, 0.9);
}
#ecgCanvas {
    width: 100%;
    height: 260px;
    display: block;
    border-radius: 0.75rem;
    background: var(--bg);
    border: 1px solid var(--border);
}

/* Metrics */
.metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 0.8rem;
    margin-bottom: 0.8rem;
}
.metric {
    background: radial-gradient(circle at top left, var(--accent-soft), var(--card-bg));
    border: 1px solid var(--border);
    border-radius: 0.8rem;
    padding: 0.6rem 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}
.metric.status-metric {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, rgba(2, 6, 23, 0.95), rgba(8, 47, 73, 0.95));
}
.metric .label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--muted);
}
.metric .value {
    font-size: 0.95rem;
    font-variant-numeric: tabular-nums;
    display: flex;
    align-items: baseline;
    gap: 0.25rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.hint {
    font-size: 0.75rem;
    color: var(--muted);
    margin: 0.4rem 0 0;
    text-align: center;
}

@media (max-width: 600px) {
    #ecgCanvas {
        height: 200px;
    }
    .metrics {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    }
}

/* Snapshot section */
.snapshot {
  max-width: 900px;
  margin: 2rem auto 4rem;
  padding: 1.5rem;
  border-radius: 1rem;
  background: radial-gradient(circle at top left, #0f172a, #020617 60%);
  box-shadow: 0 18px 45px rgba(15, 23, 42, 0.75);
}

.snapshot h2 {
  color: #e5e7eb;
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
}

.snapshot img {
  width: 100%;
  display: block;
  background: #ffffff;
  border-radius: 0.5rem;
}

/* CSV download link below snapshot */
.download-link {
  display: inline-block;
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: #38bdf8;
  text-decoration: none;
  font-variant-numeric: tabular-nums;
}
.download-link:hover {
  text-decoration: underline;
}

/* hidden helper */
.hidden {
  display: none !important;
}