/* =========================================================
   GraphApp – CSS  |  White-Blue neutral theme
   ========================================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ── Root tokens ── */
:root {
  --bg-base:        #f0f4f8;        /* page background  */
  --bg-surface:     #ffffff;        /* card surface     */
  --bg-glass:       rgba(255,255,255,0.75);
  --bg-glass-hover: rgba(255,255,255,0.92);
  --border-glass:   rgba(99,131,176,0.18);

  --accent-1:       #2563eb;        /* royal blue        */
  --accent-2:       #3b82f6;        /* sky blue          */
  --accent-3:       #0ea5e9;        /* light blue        */
  --accent-grad:    linear-gradient(135deg, #2563eb, #0ea5e9);

  --text-primary:   #0f172a;        /* near-black slate  */
  --text-muted:     #64748b;        /* slate-500         */

  --radius-card:    1rem;
  --radius-sm:      .5rem;
  --shadow-card:    0 2px 16px rgba(37,99,235,.08), 0 1px 4px rgba(0,0,0,.04);
  --shadow-glow:    0 4px 24px rgba(37,99,235,.18);
  --transition:     .22s cubic-bezier(.4,0,.2,1);
}

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

html, body {
  height: 100%;
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg-base);
  color: var(--text-primary);
  overflow-x: hidden;
}

/* Subtle background gradient wash */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 50% at 10% 0%,   rgba(37,99,235,.07)  0%, transparent 65%),
    radial-gradient(ellipse 60% 40% at 90% 100%,  rgba(14,165,233,.06) 0%, transparent 65%);
  pointer-events: none;
  z-index: 0;
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--accent-2); border-radius: 3px; }

/* ── Navbar ── */
.navbar {
  background: rgba(255,255,255,.88) !important;
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-glass);
  padding-block: .75rem;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 1px 12px rgba(37,99,235,.07);
}

.navbar-brand {
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -.025em;
  background: var(--accent-grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.navbar-brand .brand-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px; height: 32px;
  background: var(--accent-grad);
  border-radius: 8px;
  margin-right: .5rem;
  -webkit-text-fill-color: white;
  box-shadow: 0 2px 8px rgba(37,99,235,.3);
}

/* ── Nav page links ── */
.nav-page-link {
  padding: .4rem .85rem;
  border-radius: var(--radius-sm);
  font-size: .82rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  transition: var(--transition);
  border: 1px solid transparent;
}
.nav-page-link:hover {
  background: rgba(37,99,235,.07);
  color: var(--accent-1);
}
.nav-page-link.active {
  background: rgba(37,99,235,.08);
  border-color: rgba(37,99,235,.25);
  color: var(--accent-1);
}

/* ── Glass card ── */
.glass-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--shadow-card);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.glass-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,.8), transparent);
  pointer-events: none;
}

.glass-card:hover {
  background: var(--bg-glass-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

/* ── Upload zone ── */
.upload-zone {
  border: 2px dashed rgba(37,99,235,.25);
  border-radius: var(--radius-card);
  padding: 2.5rem;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  background: rgba(255,255,255,.6);
}

.upload-zone:hover,
.upload-zone.drag-over {
  border-color: var(--accent-1);
  background: rgba(37,99,235,.05);
  box-shadow: 0 0 0 4px rgba(37,99,235,.1);
}

.upload-zone .upload-icon {
  font-size: 2.5rem;
  margin-bottom: .75rem;
  display: block;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-6px); }
}

/* ── Stat badge ── */
.stat-badge {
  background: rgba(37,99,235,.07);
  border: 1px solid rgba(37,99,235,.15);
  border-radius: var(--radius-sm);
  padding: .35rem .7rem;
  font-size: .78rem;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  white-space: nowrap;
}

.stat-badge strong { color: var(--text-primary); font-weight: 600; }

/* ── Accent button ── */
.btn-accent {
  background: var(--accent-grad);
  border: none;
  color: #fff;
  font-weight: 600;
  border-radius: var(--radius-sm);
  padding: .5rem 1.25rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  box-shadow: 0 2px 10px rgba(37,99,235,.25);
}

.btn-accent::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,0);
  transition: var(--transition);
}

.btn-accent:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(37,99,235,.35);
  color: #fff;
}

.btn-accent:hover::after { background: rgba(255,255,255,.1); }

.btn-ghost {
  background: rgba(255,255,255,.7);
  border: 1px solid var(--border-glass);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  padding: .5rem 1.25rem;
  transition: var(--transition);
}

.btn-ghost:hover {
  background: rgba(37,99,235,.07);
  color: var(--accent-1);
  border-color: rgba(37,99,235,.3);
}

/* ── Chart container ── */
#chart-container {
  width: 100%;
  height: 600px;
  min-height: 400px;
  transition: opacity .4s ease;
}

#chart-container:fullscreen {
  background: var(--bg-surface);
}

/* ── Series toggle pills ── */
.series-pill {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .3rem .75rem;
  border-radius: 999px;
  border: 1px solid var(--border-glass);
  background: rgba(255,255,255,.7);
  cursor: pointer;
  font-size: .8rem;
  transition: var(--transition);
  user-select: none;
  color: var(--text-muted);
}

.series-pill .dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.series-pill.active { border-color: currentColor; }
.series-pill:hover  { background: rgba(37,99,235,.06); }

/* ── Chart type selector ── */
.chart-type-btn {
  background: rgba(255,255,255,.7);
  border: 1px solid var(--border-glass);
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  padding: .4rem .85rem;
  font-size: .8rem;
  cursor: pointer;
  transition: var(--transition);
}

.chart-type-btn.active,
.chart-type-btn:hover {
  background: rgba(37,99,235,.08);
  border-color: rgba(37,99,235,.35);
  color: var(--accent-1);
  font-weight: 500;
}

/* ── Data table ── */
.data-table-wrapper {
  max-height: 280px;
  overflow-y: auto;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-glass);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .82rem;
}

.data-table th {
  background: rgba(37,99,235,.07);
  color: var(--text-primary);
  padding: .55rem 1rem;
  text-align: left;
  position: sticky;
  top: 0;
  z-index: 1;
  font-weight: 600;
  letter-spacing: .04em;
  font-size: .75rem;
  text-transform: uppercase;
  border-bottom: 1px solid var(--border-glass);
}

.data-table td {
  padding: .45rem 1rem;
  color: var(--text-muted);
  border-bottom: 1px solid rgba(99,131,176,.1);
  font-variant-numeric: tabular-nums;
}

.data-table tr:hover td {
  background: rgba(37,99,235,.04);
  color: var(--text-primary);
}

.data-table tr:last-child td { border-bottom: none; }

/* ── Toast ── */
.toast-custom {
  background: rgba(255,255,255,.97) !important;
  border: 1px solid var(--border-glass);
  backdrop-filter: blur(12px);
  color: var(--text-primary) !important;
  box-shadow: var(--shadow-glow);
}

/* ── Empty / loading state ── */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  gap: .75rem;
  color: var(--text-muted);
}

.spinner-ring {
  width: 40px; height: 40px;
  border: 3px solid rgba(37,99,235,.15);
  border-top-color: var(--accent-1);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── Responsive tweaks ── */
@media (max-width: 576px) {
  #chart-container  { height: 320px; }
  .upload-zone      { padding: 1.5rem 1rem; }
  .glass-card       { border-radius: .75rem; }
}

/* ── Section label ── */
.section-label {
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: .6rem;
}

/* ── Separator line ── */
.sep { border-color: var(--border-glass) !important; margin-block: 1.25rem; }

/* ── Form controls ── */
.form-select, .form-control {
  background-color: rgba(255,255,255,.8) !important;
  border-color: var(--border-glass) !important;
  color: var(--text-primary) !important;
}

.form-select:focus, .form-control:focus {
  border-color: var(--accent-2) !important;
  box-shadow: 0 0 0 3px rgba(37,99,235,.12) !important;
}

.form-check-input:checked {
  background-color: var(--accent-1);
  border-color: var(--accent-1);
}

.form-check-input:focus {
  box-shadow: 0 0 0 3px rgba(37,99,235,.15);
}

/* ── PWA install banner ── */
#install-banner {
  display: none;
  background: linear-gradient(135deg, rgba(37,99,235,.08), rgba(14,165,233,.06));
  border: 1px solid rgba(37,99,235,.2);
  border-radius: var(--radius-card);
  padding: 1rem 1.25rem;
}