/* UDID Toolbox — monochrome, borderless, motion-first, system theme */

:root {
  --bg: #050505;
  --fg: #f4f4f4;
  --muted: #8a8a8a;
  --dim: #2a2a2a;
  --line: rgba(255, 255, 255, 0.08);
  --glow: rgba(255, 255, 255, 0.04);
  --nav-bg: rgba(5, 5, 5, 0.72);
  --nav-mobile-bg: rgba(5, 5, 5, 0.96);
  --atmosphere-1: rgba(255, 255, 255, 0.07);
  --atmosphere-2: rgba(255, 255, 255, 0.03);
  --status-dot: #cfcfcf;
  --status-ping: rgba(255, 255, 255, 0.4);
  --btn-shine: rgba(255, 255, 255, 0.35);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --font: "SF Pro Display", "Segoe UI", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: "SF Mono", "Cascadia Code", "Consolas", ui-monospace, monospace;
  --nav-h: 64px;
  --safe-b: env(safe-area-inset-bottom, 0px);
  --theme-transition: background-color 0.45s var(--ease), color 0.45s var(--ease), border-color 0.45s var(--ease), box-shadow 0.45s var(--ease);
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f7f7f7;
    --fg: #0a0a0a;
    --muted: #666666;
    --dim: #e8e8e8;
    --line: rgba(0, 0, 0, 0.09);
    --glow: rgba(0, 0, 0, 0.04);
    --nav-bg: rgba(247, 247, 247, 0.82);
    --nav-mobile-bg: rgba(247, 247, 247, 0.98);
    --atmosphere-1: rgba(0, 0, 0, 0.04);
    --atmosphere-2: rgba(0, 0, 0, 0.02);
    --status-dot: #2a2a2a;
    --status-ping: rgba(0, 0, 0, 0.22);
    --btn-shine: rgba(255, 255, 255, 0.45);
  }
}

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

html {
  color-scheme: light dark;
  scroll-behavior: smooth;
  overflow-x: hidden;
  max-width: 100%;
}

body {
  min-height: 100dvh;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  font-weight: 400;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  transition: var(--theme-transition);
}

/* Atmosphere — soft radial wash, no cards */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, var(--atmosphere-1), transparent 55%),
    radial-gradient(ellipse 60% 40% at 100% 100%, var(--atmosphere-2), transparent 50%);
  z-index: 0;
  transition: opacity 0.45s var(--ease);
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

ul { list-style: none; }

.app {
  position: relative;
  z-index: 1;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 100%;
  overflow-x: clip;
}

/* ——— Nav ——— */
.nav {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(1.25rem, 4vw, 3rem);
  backdrop-filter: blur(18px) saturate(1.2);
  -webkit-backdrop-filter: blur(18px) saturate(1.2);
  background: var(--nav-bg);
  transition: var(--theme-transition);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: opacity 0.3s var(--ease);
}

.brand:hover { opacity: 0.7; }

.brand-mark {
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
}

.brand-mark svg {
  width: 100%;
  height: 100%;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(1rem, 3vw, 2rem);
}

.nav-links a,
.nav-links button {
  font-size: 0.875rem;
  color: var(--muted);
  letter-spacing: 0.02em;
  transition: color 0.3s var(--ease);
  position: relative;
}

.nav-links a:hover,
.nav-links button:hover,
.nav-links a.is-active {
  color: var(--fg);
}

.nav-links a.is-active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6px;
  height: 1px;
  background: var(--fg);
  transform-origin: left;
  animation: lineIn 0.45s var(--ease-out) both;
}

.lang-seg {
  display: inline-flex;
  align-items: center;
  gap: 0;
  box-shadow: inset 0 0 0 1px var(--line);
}

.lang-seg .lang-opt {
  min-width: 2.4rem;
  padding: 0.35rem 0.55rem;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-align: center;
  color: var(--muted);
  text-decoration: none;
}

.lang-seg .lang-opt:hover {
  color: var(--fg);
  background: var(--glow);
}

.lang-seg .lang-opt.is-active {
  color: var(--bg);
  background: var(--fg);
}

.nav-links .lang-seg a.is-active::after {
  display: none;
}

@keyframes lineIn {
  from { transform: scaleX(0); opacity: 0; }
  to { transform: scaleX(1); opacity: 1; }
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.75rem;
  color: var(--muted);
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--status-dot);
  box-shadow: 0 0 0 0 var(--status-ping);
  animation: ping 2.2s var(--ease) infinite;
}

@keyframes ping {
  0% { box-shadow: 0 0 0 0 var(--status-ping); }
  70% { box-shadow: 0 0 0 8px transparent; }
  100% { box-shadow: 0 0 0 0 transparent; }
}

/* ——— Views (SPA) ——— */
.stage {
  flex: 1;
  position: relative;
  width: min(1120px, 100%);
  max-width: 100%;
  min-width: 0;
  margin: 0 auto;
  padding: clamp(1.5rem, 4vw, 3.5rem) clamp(1.25rem, 4vw, 3rem) calc(3rem + var(--safe-b));
  overflow-x: clip;
  box-sizing: border-box;
}

.view {
  display: none;
  opacity: 0;
  transform: translateY(18px) scale(0.985);
  filter: blur(4px);
  pointer-events: none;
}

.view.is-active {
  display: block;
  pointer-events: auto;
  animation: viewIn 0.7s var(--ease-out) both;
}

.view.is-leaving {
  display: block;
  animation: viewOut 0.35s var(--ease) both;
  pointer-events: none;
  position: absolute;
  inset: 0;
  padding: inherit;
}

@keyframes viewIn {
  from {
    opacity: 0;
    transform: translateY(18px) scale(0.985);
    filter: blur(4px);
  }
  to {
    opacity: 1;
    transform: none;
    filter: blur(0);
  }
}

@keyframes viewOut {
  from {
    opacity: 1;
    transform: none;
    filter: blur(0);
  }
  to {
    opacity: 0;
    transform: translateY(-10px) scale(0.99);
    filter: blur(3px);
  }
}

/* ——— Hero ——— */
.hero {
  min-height: calc(100dvh - var(--nav-h) - 6rem);
  display: grid;
  align-content: center;
  gap: clamp(1.5rem, 4vw, 2.75rem);
  padding-top: clamp(1rem, 3vw, 2rem);
}

.eyebrow {
  font-size: 0.75rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  animation: rise 0.8s var(--ease-out) 0.05s both;
}

.hero h1 {
  font-size: clamp(2.6rem, 8vw, 5.4rem);
  font-weight: 560;
  letter-spacing: -0.035em;
  line-height: 1.05;
  max-width: 12ch;
  animation: rise 0.85s var(--ease-out) 0.12s both;
}

.hero-lead {
  max-width: 36ch;
  color: var(--muted);
  font-size: clamp(1rem, 2.2vw, 1.2rem);
  animation: rise 0.85s var(--ease-out) 0.2s both;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(22px); }
  to { opacity: 1; transform: none; }
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  align-items: center;
  animation: rise 0.9s var(--ease-out) 0.28s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  min-height: 52px;
  padding: 0 1.45rem;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  border-radius: 0;
  transition:
    background 0.35s var(--ease),
    color 0.35s var(--ease),
    transform 0.35s var(--ease),
    opacity 0.35s var(--ease);
  position: relative;
  overflow: hidden;
}

.btn svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.btn-primary {
  background: var(--fg);
  color: var(--bg);
}

.btn-primary::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, transparent 20%, var(--btn-shine) 50%, transparent 80%);
  transform: translateX(-120%);
  transition: transform 0.7s var(--ease);
}

.btn-primary:hover::after {
  transform: translateX(120%);
}

.btn-primary:hover {
  transform: translateY(-2px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-ghost {
  background: transparent;
  color: var(--fg);
  box-shadow: inset 0 0 0 1px var(--line);
}

.btn-ghost:hover {
  background: var(--glow);
  transform: translateY(-2px);
}

.meta-line {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  color: var(--muted);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  animation: rise 0.9s var(--ease-out) 0.36s both;
}

.meta-line span {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.meta-line span::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.55;
}

/* ——— Sections ——— */
.section {
  margin-top: clamp(4rem, 10vw, 7rem);
  padding-top: clamp(2rem, 5vw, 3rem);
  position: relative;
}

.section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 48px;
  height: 1px;
  background: var(--fg);
  opacity: 0.35;
}

.section-label {
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1rem;
}

.section h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.2rem);
  font-weight: 550;
  letter-spacing: -0.025em;
  margin-bottom: 0.75rem;
}

.section p {
  color: var(--muted);
  max-width: 48ch;
  font-size: 1.02rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
  margin-top: 2.5rem;
}

@media (max-width: 820px) {
  .grid-3 { grid-template-columns: 1fr; gap: 2rem; }
}

.feature {
  padding-top: 1.25rem;
  position: relative;
}

.feature::before {
  content: attr(data-num);
  display: block;
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--muted);
  margin-bottom: 0.85rem;
  font-variant-numeric: tabular-nums;
}

.feature h3 {
  font-size: 1.15rem;
  font-weight: 550;
  margin-bottom: 0.55rem;
  letter-spacing: -0.02em;
}

.feature p {
  font-size: 0.95rem;
}

.steps {
  display: grid;
  gap: 0;
  margin-top: 2rem;
}

.step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 1rem;
  padding: 1.35rem 0;
  align-items: start;
  position: relative;
}

.step + .step::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--line);
}

.step-num {
  font-size: 1.4rem;
  font-weight: 500;
  letter-spacing: -0.03em;
  color: var(--fg);
  opacity: 0.9;
}

.step h3 {
  font-size: 1.05rem;
  font-weight: 550;
  margin-bottom: 0.3rem;
}

.step p {
  font-size: 0.95rem;
}

/* ——— Waiting / Assist ——— */
.panel {
  max-width: 560px;
  margin: 0 auto;
  text-align: center;
  padding-top: clamp(2rem, 8vw, 5rem);
}

.panel h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  letter-spacing: -0.03em;
  font-weight: 560;
  margin: 1rem 0 0.75rem;
}

.panel .lead {
  color: var(--muted);
  margin-bottom: 2rem;
}

.orbit {
  width: 88px;
  height: 88px;
  margin: 0 auto;
  position: relative;
}

.orbit-ring {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1px var(--line);
  animation: spin 6s linear infinite;
}

.orbit-ring::before {
  content: "";
  position: absolute;
  top: -3px;
  left: 50%;
  width: 6px;
  height: 6px;
  margin-left: -3px;
  border-radius: 50%;
  background: var(--fg);
}

.orbit-core {
  position: absolute;
  inset: 28%;
  border-radius: 50%;
  background: var(--fg);
  animation: corePulse 1.8s var(--ease) infinite;
}

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

@keyframes corePulse {
  0%, 100% { transform: scale(0.88); opacity: 0.55; }
  50% { transform: scale(1); opacity: 1; }
}

.room-code {
  font-family: var(--mono);
  font-size: clamp(2.2rem, 7vw, 3.4rem);
  letter-spacing: 0.28em;
  font-weight: 500;
  margin: 1.5rem 0 0.5rem;
  padding-left: 0.28em;
}

.share-box {
  margin-top: 1.75rem;
  display: grid;
  gap: 0.75rem;
}

.share-url {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--muted);
  word-break: break-all;
  padding: 1rem 0;
  background: transparent;
  text-align: left;
  box-shadow: inset 0 -1px 0 var(--line), inset 0 1px 0 var(--line);
}

.hint-list {
  margin-top: 2.5rem;
  text-align: left;
  display: grid;
  gap: 0.85rem;
}

.hint-list li {
  color: var(--muted);
  font-size: 0.92rem;
  padding-left: 1.1rem;
  position: relative;
}

.hint-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--fg);
  opacity: 0.5;
}

/* ——— Result ——— */
.result-wrap {
  max-width: 720px;
  margin: 0 auto;
  padding-top: clamp(1rem, 4vw, 2.5rem);
}

.result-head {
  margin-bottom: 2.5rem;
}

.result-head .eyebrow {
  animation: none;
}

.result-head h1 {
  font-size: clamp(1.9rem, 4vw, 2.8rem);
  letter-spacing: -0.03em;
  font-weight: 560;
  margin-top: 0.5rem;
}

.field {
  padding: 1.35rem 0;
  position: relative;
}

.field + .field::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--line);
}

.field-label {
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.55rem;
}

.field-value {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: clamp(1rem, 2.5vw, 1.2rem);
  word-break: break-all;
  overflow-wrap: anywhere;
  min-width: 0;
  max-width: 100%;
}

.field-value > span,
.field-value > a {
  min-width: 0;
  max-width: 100%;
  overflow-wrap: anywhere;
}

.field-value.mono {
  font-family: var(--mono);
  letter-spacing: 0.02em;
}

.icon-btn {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  color: var(--muted);
  transition: color 0.3s var(--ease), background 0.3s var(--ease), transform 0.3s var(--ease);
}

.icon-btn:hover {
  color: var(--fg);
  background: var(--glow);
  transform: scale(1.05);
}

.icon-btn svg {
  width: 18px;
  height: 18px;
}

.icon-btn.is-ok {
  color: var(--fg);
  animation: pop 0.45s var(--ease-out);
}

@keyframes pop {
  0% { transform: scale(1); }
  40% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.result-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2.25rem;
}

/* ——— Toast ——— */
.toast {
  position: fixed;
  left: 50%;
  bottom: calc(1.5rem + var(--safe-b));
  transform: translateX(-50%) translateY(120%);
  background: var(--fg);
  color: var(--bg);
  padding: 0.85rem 1.25rem;
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  z-index: 100;
  opacity: 0;
  transition: transform 0.5s var(--ease-out), opacity 0.5s var(--ease);
  pointer-events: none;
}

.toast.is-show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* ——— Footer ——— */
.footer {
  padding: 2rem clamp(1.25rem, 4vw, 3rem) calc(1.5rem + var(--safe-b));
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: space-between;
  align-items: center;
  color: var(--muted);
  font-size: 0.8rem;
  width: min(1120px, 100%);
  margin: 0 auto;
}

.footer a {
  color: var(--muted);
  transition: color 0.3s var(--ease);
}

.footer a:hover { color: var(--fg); }

/* ——— Knowledge accordion ——— */
.faq {
  margin-top: 1.75rem;
  display: grid;
  gap: 0;
}

.faq-item {
  padding: 1.25rem 0;
  position: relative;
}

.faq-item + .faq-item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--line);
}

.faq-q {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  text-align: left;
  font-size: 1.05rem;
  font-weight: 550;
  letter-spacing: -0.015em;
}

.faq-icon {
  width: 20px;
  height: 20px;
  position: relative;
  flex-shrink: 0;
  opacity: 0.55;
  transition: transform 0.4s var(--ease), opacity 0.3s;
}

.faq-icon::before,
.faq-icon::after {
  content: "";
  position: absolute;
  background: currentColor;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.faq-icon::before {
  width: 12px;
  height: 1px;
}

.faq-icon::after {
  width: 1px;
  height: 12px;
  transition: transform 0.4s var(--ease), opacity 0.3s;
}

.faq-item.is-open .faq-icon {
  opacity: 1;
}

.faq-item.is-open .faq-icon::after {
  transform: translate(-50%, -50%) rotate(90deg);
  opacity: 0;
}

.faq-a {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.45s var(--ease);
}

.faq-item.is-open .faq-a {
  grid-template-rows: 1fr;
}

.faq-a > div {
  overflow: hidden;
}

.faq-a p {
  padding-top: 0.75rem;
  color: var(--muted);
  font-size: 0.95rem;
  max-width: 56ch;
}

/* ——— Mobile nav ——— */
.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  place-items: center;
}

.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
  display: block;
  width: 18px;
  height: 1px;
  background: var(--fg);
  position: relative;
  transition: transform 0.35s var(--ease), opacity 0.3s;
}

.nav-toggle span::before,
.nav-toggle span::after {
  content: "";
  position: absolute;
  left: 0;
}

.nav-toggle span::before { top: -6px; }
.nav-toggle span::after { top: 6px; }

.nav-toggle.is-open span {
  background: transparent;
}

.nav-toggle.is-open span::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle.is-open span::after {
  top: 0;
  transform: rotate(-45deg);
}

@media (max-width: 720px) {
  .nav-toggle { display: grid; }

  .nav-links {
    position: fixed;
    inset: var(--nav-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.5rem 1.25rem 1.25rem;
    background: var(--nav-mobile-bg);
    backdrop-filter: blur(16px);
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.35s var(--ease), transform 0.35s var(--ease);
  }

  .nav-links.is-open {
    opacity: 1;
    transform: none;
    pointer-events: auto;
  }

  .nav-links a,
  .nav-links button {
    padding: 0.95rem 0;
    font-size: 1rem;
    text-align: left;
  }

  .nav-links a.is-active::after { display: none; }

  .status-pill { display: none; }

  .hero h1 { max-width: none; }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}