/* Base styles */
:root {
  --bg: #0b1220;
  --panel: #111827;
  --panel-border: #1f2937;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --accent: #22c55e; /* green */
  --accent-strong: #16a34a;
  --input-bg: #0f172a;
  --input-border: #334155;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: radial-gradient(1200px 600px at 10% -10%, #0e1630 0%, var(--bg) 40%) no-repeat fixed;
  color: var(--text);
  line-height: 1.5;
}

/* Header */
.app-header {
  position: sticky;
  top: 0;
  backdrop-filter: saturate(1.3) blur(6px);
  background: rgba(11, 18, 32, 0.6);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  z-index: 10;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.title {
  margin: 0;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.2px;
}

.badge {
  display: inline-block;
  font-size: 12px;
  color: #052e16;
  background: linear-gradient(180deg, #34d399 0%, #22c55e 100%);
  border-radius: 999px;
  padding: 4px 10px;
  font-weight: 700;
}

/* Layout */
.container {
  max-width: 1100px;
  margin: 24px auto;
  padding: 0 20px 40px;
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 20px;
}

@media (max-width: 980px) {
  .container {
    grid-template-columns: 1fr;
  }
}

/* Panels */
.panel {
  background: linear-gradient(180deg, #0f172a 0%, var(--panel) 100%);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 16px 16px 18px;
}

.panel-title {
  margin: 0 0 10px 2px;
  font-size: 14px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

/* Controls */
.control-group {
  margin-bottom: 14px;
}

.control-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

@media (max-width: 520px) {
  .control-row {
    grid-template-columns: 1fr;
  }
}

.control-label {
  display: block;
  margin: 0 0 6px;
  font-size: 13px;
  color: var(--muted);
}

input[type="file"],
input[type="number"],
input[type="range"] {
  width: 100%;
}

input[type="file"],
input[type="number"] {
  background: var(--input-bg);
  color: var(--text);
  border: 1px solid var(--input-border);
  border-radius: 10px;
  padding: 10px 12px;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input[type="number"]::placeholder {
  color: #6b7280;
}

input[type="file"]:focus,
input[type="number"]:focus {
  border-color: #475569;
  box-shadow: 0 0 0 3px rgba(71, 85, 105, 0.25);
}

/* Range slider */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  background: #0b1220;
  border: 1px solid var(--input-border);
  border-radius: 999px;
  outline: none;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #052e16;
  cursor: pointer;
  box-shadow: 0 0 0 4px rgba(34, 197, 94, 0.18);
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #052e16;
  cursor: pointer;
  box-shadow: 0 0 0 4px rgba(34, 197, 94, 0.18);
}

.hint {
  margin: 6px 2px 0;
  color: var(--muted);
  font-size: 12px;
}

.tiny-hint {
  margin: 6px 2px 0;
  color: #94a3b8;
  font-size: 12px;
}

.btn-primary {
  display: inline-block;
  margin-top: 4px;
  padding: 10px 16px;
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-strong) 100%);
  color: #052e16;
  border: none;
  border-radius: 999px;
  font-weight: 800;
  cursor: pointer;
  transition: transform 0.05s ease, filter 0.2s ease, opacity 0.2s ease;
  box-shadow: 0 8px 24px rgba(34, 197, 94, 0.25);
}

.btn-primary:hover {
  filter: brightness(1.05);
}

.btn-primary:active {
  transform: translateY(1px);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
}

/* Preview */
.preview-wrapper {
  position: relative;
  width: 100%;
  background: #0a0f1b;
  border: 1px dashed #1e293b;
  border-radius: 12px;
  min-height: 320px;
  overflow: hidden;
}

#imageCanvas {
  display: block;
  width: 100%;
  height: auto;
}

#overlayCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #94a3b8;
  font-size: 14px;
  letter-spacing: 0.4px;
  text-align: center;
  padding: 14px;
}

/* Results */
.results {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--panel-border);
}

.result-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 15px;
}

.result-sub {
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
}

/* Footer */
.footer {
  padding: 20px 0 32px;
  color: var(--muted);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
  font-size: 12px;
  opacity: 0.8;
}

/* Desktop-only overlay */
.desktop-only-block {
  position: fixed;
  inset: 0;
  display: none; /* toggled via JS */
  align-items: center;
  justify-content: center;
  background: rgba(8, 12, 22, 0.92);
  backdrop-filter: blur(6px);
  z-index: 1000;
}

.desktop-only-card {
  background: linear-gradient(180deg, #0f172a 0%, var(--panel) 100%);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 20px 22px;
  max-width: 520px;
  text-align: center;
}

.desktop-only-card h2 {
  margin: 0 0 8px;
  font-size: 20px;
}

.desktop-only-card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}