/* =============================
   QuizForge - High-end UI Theme
   Only CSS changes; no HTML/JS edits
   ============================= */

/* Design Tokens */
:root {
  /* Palette */
  --bg: #0f1220;
  --bg-2: #12162a;
  --surface: rgba(255, 255, 255, 0.06);
  --surface-strong: rgba(255, 255, 255, 0.1);
  --text: #e7e9ee;
  --muted: #a1a6b3;
  --primary: #7c3aed;   /* violet-600 */
  --primary-2: #22d3ee; /* cyan-400 */
  --accent: #10b981;    /* emerald-500 */
  --accent-2: #f59e0b;  /* amber-500 */
  --success: #16a34a;
  --danger: #ef4444;

  /* Radii, shadow, blur */
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --inner-shadow: inset 0 1px 0 rgba(255,255,255,0.06);
  --glass: blur(14px) saturate(135%);

  /* Gradients */
  --grad-primary: linear-gradient(135deg, var(--primary), var(--primary-2));
  --grad-accent: linear-gradient(135deg, var(--accent), var(--accent-2));
  --grad-bg: radial-gradient(1200px 600px at 10% -10%, rgba(124, 58, 237, 0.35), transparent 55%),
             radial-gradient(1000px 500px at 100% 0%, rgba(34, 211, 238, 0.35), transparent 50%),
             radial-gradient(900px 500px at 0% 100%, rgba(16, 185, 129, 0.25), transparent 55%),
             linear-gradient(180deg, var(--bg), var(--bg-2));

  /* Motion */
  --elevate: translateY(-3px);
  --time-fast: 140ms;
  --time-med: 280ms;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f7fb;
    --bg-2: #eef1f9;
    --surface: rgba(255, 255, 255, 0.75);
    --surface-strong: rgba(255,255,255,0.92);
    --text: #151725;
    --muted: #5f6475;
    --shadow: 0 10px 30px rgba(12, 28, 50, 0.15);
    --glass: blur(10px) saturate(140%);
    --grad-bg: radial-gradient(1200px 700px at 0% -10%, rgba(124, 58, 237, 0.18), transparent 50%),
               radial-gradient(900px 500px at 100% 0%, rgba(34, 211, 238, 0.18), transparent 50%),
               linear-gradient(180deg, var(--bg), var(--bg-2));
  }
}

/* Global Reset and Base */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, "Helvetica Neue", Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: var(--grad-bg);
  background-attachment: fixed;
  min-height: 100vh;
}

/* Subtle animated gradient shimmer */
@keyframes bgFloat {
  0% { background-position: 0% 0%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 0%; }
}
body { background-size: 200% 200%; }
@media (prefers-reduced-motion: no-preference) {
  body { animation: bgFloat 20s ease-in-out infinite; }
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 20;
  padding: 12px 22px;
  background: linear-gradient(90deg, rgba(0,0,0,0.25), rgba(0,0,0,0.0));
  backdrop-filter: var(--glass);
  -webkit-backdrop-filter: var(--glass);
  box-shadow: var(--shadow);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

/* Brand */
.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}
.logo-mark {
  position: relative;
  display: inline-grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: radial-gradient(120% 120% at 30% 20%, rgba(124,58,237,0.55), rgba(34,211,238,0.55) 60%, rgba(16,185,129,0.4));
  box-shadow: 0 8px 24px rgba(124,58,237,0.35), inset 0 1px 0 rgba(255,255,255,0.12);
  overflow: hidden;
}
.logo-mark::after {
  content: "";
  position: absolute; inset: -30% -30% auto auto;
  width: 60%; height: 60%;
  background: radial-gradient(100% 100% at 50% 50%, rgba(255,255,255,0.7), transparent 60%);
  filter: blur(6px);
}
.logo-text { display: inline-flex; gap: 0; font-weight: 900; letter-spacing: 0.4px; font-size: clamp(18px, 2vw, 22px); }
.logo-quiz { color: var(--text); opacity: 0.9; }
.logo-forge {
  background: var(--grad-accent);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Hover micro-interactions */
@media (prefers-reduced-motion: no-preference) {
  .logo:hover .logo-mark { transform: translateY(-2px) scale(1.04); transition: transform var(--time-med) ease, filter var(--time-fast) ease; filter: saturate(120%); }
  .logo:hover .logo-forge { filter: brightness(1.1); }
}

/* Layout */
.container {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 22px;
  max-width: 1200px;
  margin: 24px auto;
  padding: 0 20px;
}
@media (max-width: 960px) {
  .container { grid-template-columns: 1fr; }
}

.sidebar { display: flex; flex-direction: column; gap: 20px; }
.content {
  border-radius: var(--radius);
  padding: 22px;
  background: var(--surface);
  backdrop-filter: var(--glass);
  -webkit-backdrop-filter: var(--glass);
  box-shadow: var(--shadow), var(--inner-shadow);
  border: 1px solid rgba(255,255,255,0.1);
}
.content h2 { margin: 0 0 12px; font-weight: 800; letter-spacing: 0.2px; }

/* Blocks */
.block {
  border-radius: var(--radius);
  padding: 18px;
  background: var(--surface);
  backdrop-filter: var(--glass);
  -webkit-backdrop-filter: var(--glass);
  box-shadow: var(--shadow), var(--inner-shadow);
  border: 1px solid rgba(255,255,255,0.1);
}
.block h2 { margin: 0 0 12px; font-weight: 700; }

/* File Upload */
.uploader {
  position: relative;
  border: 2px dashed rgba(255,255,255,0.22);
  border-radius: var(--radius);
  padding: 34px 14px;
  text-align: center;
  cursor: pointer;
  transition: transform var(--time-med) ease, box-shadow var(--time-med) ease, border-color var(--time-fast) ease, background var(--time-fast) ease;
  background: linear-gradient(180deg, rgba(255,255,255,0.06), rgba(255,255,255,0.02));
}
.uploader:hover {
  transform: var(--elevate);
  border-color: rgba(255,255,255,0.35);
  box-shadow: 0 12px 30px rgba(124, 58, 237, 0.25);
}
.uploader.dragover {
  border-color: transparent;
  background:
    radial-gradient(200px 120px at 50% -10%, rgba(124,58,237,0.35), transparent 70%),
    radial-gradient(220px 140px at 50% 110%, rgba(34,211,238,0.35), transparent 70%),
    linear-gradient(180deg, rgba(255,255,255,0.12), rgba(255,255,255,0.04));
  box-shadow: 0 14px 36px rgba(34, 211, 238, 0.28), inset 0 0 0 2px rgba(255,255,255,0.06);
}
.uploader p { margin: 6px 0; }
.uploader .small { color: var(--muted); font-size: 12px; }
.uploader input { display: none; }
.status { font-size: 13px; color: var(--muted); margin-top: 8px; }

/* Inputs & Controls */
label { font-size: 13px; color: var(--muted); }

/* Difficulty select (inserted by JS) */
#difficultySel {
  color: var(--text);
  font-weight: 800;
  min-height: 40px;
  font-size: 14px;
  padding: 8px 34px 8px 12px; /* room for custom caret */
  border-radius: var(--radius-sm);
  outline: none;
  /* Persistent visible color (fallback) */
  background-image: linear-gradient(90deg, rgba(124,58,237,0.65) 0 8px, transparent 8px),
                    linear-gradient(180deg, rgba(255,255,255,0.16), rgba(255,255,255,0.06));
  background-color: rgba(17, 24, 39, 0.35);
  border: 2px solid rgba(124,58,237,0.75);
  box-shadow: 0 8px 24px rgba(124,58,237,0.25), inset 0 1px 0 rgba(255,255,255,0.06);
  transition: box-shadow var(--time-fast) ease, transform var(--time-fast) ease, filter var(--time-fast) ease;
  appearance: none; /* custom caret */
  -webkit-appearance: none;
  background-repeat: no-repeat;
  background-position: right 10px center, left top;
}
#difficultySel:hover { transform: var(--elevate); filter: brightness(1.05); }
#difficultySel:focus-visible { box-shadow: 0 0 0 4px rgba(34,211,238,0.35), inset 0 1px 0 rgba(255,255,255,0.06); }

/* Custom caret */
#difficultySel {
  background-image:
    url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="%23e7e9ee" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="6 9 12 15 18 9"/></svg>'),
    linear-gradient(180deg, rgba(255,255,255,0.16), rgba(255,255,255,0.06));
}

/* Range sliders */
input[type=range] {
  -webkit-appearance: none;
  width: 100%;
  height: 22px;
  background: transparent;
  margin: 8px 0 14px;
}
input[type=range]::-webkit-slider-runnable-track {
  height: 8px;
  background: linear-gradient(90deg, rgba(124,58,237,0.8), rgba(34,211,238,0.8));
  border-radius: 999px;
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.25);
}
input[type=range]::-moz-range-track {
  height: 8px;
  background: linear-gradient(90deg, rgba(124,58,237,0.8), rgba(34,211,238,0.8));
  border-radius: 999px;
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.25);
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--surface-strong);
  border: 2px solid white;
  box-shadow: 0 4px 10px rgba(0,0,0,0.35);
  margin-top: -5px;
  transition: transform var(--time-fast) ease;
}
input[type=range]::-webkit-slider-thumb:hover { transform: scale(1.08); }
input[type=range]::-moz-range-thumb {
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--surface-strong);
  border: 2px solid white;
  box-shadow: 0 4px 10px rgba(0,0,0,0.35);
  transition: transform var(--time-fast) ease;
}
input[type=range]::-moz-range-thumb:hover { transform: scale(1.08); }

/* Quiz Title input and preview title */
.text-field {
  width: 100%;
  color: var(--text);
  background: linear-gradient(180deg, rgba(255,255,255,0.16), rgba(255,255,255,0.06));
  background-color: rgba(17, 24, 39, 0.35);
  border: 2px solid rgba(124,58,237,0.75);
  border-radius: 10px;
  padding: 10px 12px;
  box-shadow: 0 8px 24px rgba(124,58,237,0.18), inset 0 1px 0 rgba(255,255,255,0.06);
  font: inherit;
}
.text-field::placeholder { color: var(--muted); }
.text-field:focus-visible { outline: none; box-shadow: 0 0 0 4px rgba(34,211,238,0.35), inset 0 1px 0 rgba(255,255,255,0.06); }

.quiz-title { margin: 0 0 12px; font-weight: 800; letter-spacing: 0.2px; font-size: clamp(16px, 2.2vw, 20px); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  margin-top: 10px;
  padding: 12px 14px;
  border: 0;
  border-radius: var(--radius);
  font-weight: 800;
  letter-spacing: 0.2px;
  color: white;
  background: var(--grad-primary);
  box-shadow: 0 10px 24px rgba(124,58,237,0.35);
  cursor: pointer;
  transition: transform var(--time-med) ease, box-shadow var(--time-med) ease, filter var(--time-fast) ease;
}
.btn:hover { transform: var(--elevate); filter: brightness(1.05); box-shadow: 0 14px 28px rgba(124,58,237,0.45); }
.btn:active { transform: translateY(-1px); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; filter: grayscale(10%); }

.btn.outline {
  background: transparent;
  color: var(--text);
  border: 2px solid transparent;
  background-image: linear-gradient(var(--bg), var(--bg)), var(--grad-primary);
  background-origin: border-box;
  background-clip: padding-box, border-box;
  box-shadow: 0 6px 18px rgba(124,58,237,0.18);
}
.btn.outline:hover { box-shadow: 0 10px 26px rgba(34,211,238,0.28); }

/* Quiz Preview */
.quiz { display: grid; gap: 18px; }
@keyframes floatIn {
  0% { opacity: 0; transform: translateY(6px); }
  100% { opacity: 1; transform: translateY(0); }
}
.q {
  padding: 18px;
  background: linear-gradient(180deg, rgba(255,255,255,0.06), rgba(255,255,255,0.03));
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid rgba(255,255,255,0.1);
  position: relative;
  overflow: hidden;
  animation: floatIn 380ms ease both;
}
.q::before {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(600px 200px at -10% 0%, rgba(124,58,237,0.12), transparent 60%);
  pointer-events: none;
}
.q:hover { transform: var(--elevate); }
.q h3 { margin: 0 0 12px; font-size: clamp(14px, 1.8vw, 18px); font-weight: 700; }
.q ul { margin: 0; padding-left: 0; list-style: none; display: grid; gap: 8px; }
.q .answer { margin-top: 10px; font-size: 13px; color: var(--muted); }

/* Options with custom radios */
.opt {
  display: grid;
  grid-template-columns: 22px 1fr;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 12px;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  transition: background var(--time-fast) ease, transform var(--time-fast) ease, box-shadow var(--time-fast) ease, border-color var(--time-fast) ease;
}
.opt:hover { transform: translateY(-2px); background: rgba(255,255,255,0.06); box-shadow: 0 8px 20px rgba(0,0,0,0.2); }
.opt input { appearance: none; -webkit-appearance: none; width: 18px; height: 18px; margin: 0; border-radius: 50%; border: 2px solid rgba(255,255,255,0.6); background: transparent; position: relative; }
.opt input:focus-visible { outline: none; box-shadow: 0 0 0 3px rgba(34,211,238,0.35); }
.opt input::after { content: ""; position: absolute; inset: 2px; border-radius: 50%; background: transparent; transition: background var(--time-fast) ease, transform var(--time-fast) ease; }
.opt input:checked { border-color: transparent; background: var(--grad-primary); box-shadow: 0 6px 16px rgba(124,58,237,0.35); }
.opt input:checked::after { background: white; transform: scale(0.9); }
.opt span { font-size: 14px; }

/* Correct / Incorrect states */
.opt.correct { background: rgba(22,163,74,0.15); border-color: rgba(22,163,74,0.45); box-shadow: 0 8px 20px rgba(22,163,74,0.25); }
.opt.incorrect { background: rgba(239,68,68,0.15); border-color: rgba(239,68,68,0.45); box-shadow: 0 8px 20px rgba(239,68,68,0.25); }

/* Score banner */
.score-banner {
  background: linear-gradient(180deg, rgba(255,255,255,0.08), rgba(255,255,255,0.04));
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 14px 16px;
  margin-bottom: 14px;
  border: 1px solid rgba(255,255,255,0.12);
  display: none;
}
.score-banner.show { display: block; border-left: 4px solid var(--accent); }

/* Utilities & Accessibility */
:focus-visible { outline: 3px solid rgba(34,211,238,0.35); outline-offset: 2px; }

/* Dynamic brand color animation */
@keyframes logoGradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Apply animated gradient to the brand name */
.logo-text .logo-quiz,
.logo-text .logo-forge {
  background-image: linear-gradient(90deg, var(--primary), var(--primary-2), var(--accent), var(--accent-2), var(--primary));
  background-size: 250% 250%;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: logoGradientShift 6s ease-in-out infinite;
}

@media (prefers-reduced-motion: reduce) {
  .logo-text .logo-quiz,
  .logo-text .logo-forge { animation: none; }
}

/* Print (PDF export is handled by jsPDF; reduce on-page noise when printing) */
@media print {
  .navbar, .sidebar { display: none !important; }
  .container { grid-template-columns: 1fr !important; margin: 0; }
  body { background: white; color: black; }
  .content, .q, .block { box-shadow: none; backdrop-filter: none; background: white; border-color: #ddd; }
}

/*