/* ============================================================
   TOKENS
   ============================================================ */
:root {
  --black: #0a0a0a;
  --panel: #131313;
  --surface: #1a1a1a;
  --border: #2e2e2e;
  --border-soft: #232323;
  --white: #f6f6f4;
  --dim: #8a8a8a;
  --dim-2: #565656;

  --font-display: 'Noto Sans TC', 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, monospace;

  --ease: cubic-bezier(0.65, 0, 0.35, 1);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--black);
  color: var(--white);
  font-family: var(--font-display);
  min-height: 100vh;
  overflow-x: hidden;
}

body {
  background-image:
    linear-gradient(var(--border-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--border-soft) 1px, transparent 1px);
  background-size: 48px 48px;
  background-position: center;
}

::selection { background: var(--white); color: var(--black); }

:focus-visible {
  outline: 2px solid var(--white);
  outline-offset: 3px;
}

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

/* ============================================================
   TOP PROGRESS BAR
   ============================================================ */
.progress-shell {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 24px;
  background: linear-gradient(to bottom, rgba(10,10,10,0.92), rgba(10,10,10,0));
  backdrop-filter: blur(2px);
}

.progress-track {
  flex: 1;
  height: 2px;
  background: var(--border);
  position: relative;
  overflow: hidden;
}

.progress-fill {
  position: absolute;
  top: 0; left: 0; bottom: 0;
  width: 0%;
  background: var(--white);
  transition: width 0.5s var(--ease);
}

.progress-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--dim);
  white-space: nowrap;
}
.progress-sep { margin: 0 3px; color: var(--dim-2); }

/* ambient scan-line, purely decorative */
/* .scan-line {
  position: fixed;
  left: 0; right: 0;
  height: 120px;
  top: -120px;
  background: linear-gradient(to bottom, rgba(246,246,244,0.05), transparent);
  pointer-events: none;
  z-index: 1;
  animation: scan 9s linear infinite;
} */
@keyframes scan {
  0% { top: -120px; }
  100% { top: 100vh; }
}

/* ============================================================
   STAGE / SCREENS
   ============================================================ */
.stage {
  position: relative;
  z-index: 2;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 120px 24px 80px;
}

.screen {
  display: none;
  width: 100%;
  max-width: 560px;
  flex-direction: column;
  align-items: flex-start;
  gap: 20px;
}

.screen.active {
  display: flex;
  animation: enter 0.6s var(--ease);
}

@keyframes enter {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--dim);
  text-transform: uppercase;
  border: 1px solid var(--border);
  padding: 5px 10px;
}

.headline {
  font-size: clamp(30px, 6vw, 44px);
  line-height: 1.25;
  font-weight: 900;
  margin: 0;
  letter-spacing: -0.01em;
}
.headline.small { font-size: clamp(24px, 5vw, 32px); }

.sub {
  color: var(--dim);
  font-size: 15px;
  line-height: 1.8;
  margin: 0;
}

/* ============================================================
   FIELD / INPUT
   ============================================================ */
.field {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 8px;
}

.field-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--dim-2);
  text-transform: uppercase;
}

.input {
  width: 100%;
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--white);
  font-family: var(--font-display);
  font-size: 17px;
  padding: 16px 16px;
  transition: border-color 0.25s var(--ease), background 0.25s var(--ease);
}
.input::placeholder { color: var(--dim-2); }
.input:focus { border-color: var(--white); background: var(--surface); outline: none; }

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  --btn-fill: 0%;
  position: relative;
  overflow: hidden;
  margin-top: 8px;
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 15px 26px;
  background: transparent;
  border: 1px solid var(--white);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: color 0.35s var(--ease), border-color 0.35s var(--ease), opacity 0.3s;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--white);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease);
  z-index: -1;
}

.btn:hover::before,
.btn:focus-visible::before {
  transform: scaleX(1);
}

.btn:hover,
.btn:focus-visible {
  color: var(--black);
}

.btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}
.btn:disabled::before { display: none; }

.btn-arrow {
  transition: transform 0.35s var(--ease);
}
.btn:hover .btn-arrow { transform: translateX(4px); }

.hint {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--dim-2);
  letter-spacing: 0.08em;
}

/* ============================================================
   QUIZ QUESTION
   ============================================================ */
.q-index {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.15em;
  color: var(--dim-2);
}

.question {
  font-size: clamp(22px, 4.4vw, 30px);
  line-height: 1.4;
  font-weight: 700;
  margin: 0 0 6px;
}

.options {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option {
  width: 100%;
  text-align: left;
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--white);
  font-family: var(--font-display);
  font-size: 15px;
  line-height: 1.6;
  padding: 16px 18px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 14px;
  transition: border-color 0.25s var(--ease), background 0.25s var(--ease), transform 0.2s var(--ease);
}

.option:hover {
  border-color: var(--white);
  background: var(--surface);
  transform: translateX(4px);
}

.option:active { transform: translateX(4px) scale(0.99); }

.option-mark {
  flex: none;
  width: 20px;
  height: 20px;
  border: 1px solid var(--dim-2);
  border-radius: 50%;
  position: relative;
}
.option:hover .option-mark { border-color: var(--white); }
.option-mark::after {
  content: '';
  position: absolute;
  inset: 4px;
  border-radius: 50%;
  background: var(--white);
  transform: scale(0);
  transition: transform 0.2s var(--ease);
}
.option.selected .option-mark::after { transform: scale(1); }

.option.selected {
  border-color: var(--white);
  background: var(--surface);
}

/* fade-out lock while advancing */
.options.locked .option { pointer-events: none; opacity: 0.5; }
.options.locked .option.selected { opacity: 1; }

/* ============================================================
   RESULT SCREEN / REVEAL
   ============================================================ */
.user-tag {
  font-family: var(--font-mono);
  font-size: 20px;
  letter-spacing: 0.03em;
  padding: 14px 18px;
  border: 1px solid var(--border);
  background: var(--panel);
  width: 100%;
}

#userTag {
  color: var(--white);
  font-weight: 700;
}

.scramble-char {
  color: var(--dim);
}

.btn-reveal {
  border-color: var(--white);
}

/* ============================================================
   FINAL SCREEN
   ============================================================ */
.final-content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 20px;
  width: 100%;
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 480px) {
  .stage { padding: 108px 18px 60px; }
  .progress-shell { padding: 14px 16px; }
}