:root {
  --bg: #eef0f8;
  --card: rgba(255, 255, 255, 0.72);
  --panel: rgba(255, 255, 255, 0.6);
  --text: #161827;
  --muted: #5d6275;
  --border: rgba(22, 24, 39, 0.1);
  --accent: #5b4cf0;
  --accent-2: #3b6cf6;
  --accent-3: #16b6c9;
  --ok: #17915a;
  --bad: #c9362b;
  --shadow: 0 30px 80px -30px rgba(40, 30, 120, 0.35);
  --blob-opacity: 0.28;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d0f1a;
    --card: rgba(22, 24, 38, 0.72);
    --panel: rgba(255, 255, 255, 0.04);
    --text: #eceefa;
    --muted: #9ba1b8;
    --border: rgba(255, 255, 255, 0.09);
    --accent: #8b7dff;
    --accent-2: #6c9bff;
    --accent-3: #3dd6e8;
    --ok: #4ade94;
    --bad: #ff7b6b;
    --shadow: 0 30px 80px -20px rgba(0, 0, 0, 0.7);
    --blob-opacity: 0.22;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 88px 16px 48px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.55 "Space Grotesk", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  overflow-x: hidden;
}

/* ---------- Animated backdrop ---------- */
.backdrop { position: fixed; inset: 0; z-index: -1; overflow: hidden; }
.blob {
  position: absolute;
  width: 46vmax;
  height: 46vmax;
  border-radius: 50%;
  filter: blur(80px);
  opacity: var(--blob-opacity);
  animation: drift 22s ease-in-out infinite alternate;
}
.b1 { background: var(--accent); top: -14vmax; left: -10vmax; }
.b2 { background: var(--accent-2); bottom: -18vmax; right: -12vmax; animation-delay: -7s; }
.b3 { background: var(--accent-3); top: 30%; left: 55%; width: 30vmax; height: 30vmax; animation-delay: -14s; }

@keyframes drift {
  0%   { transform: translate(0, 0) scale(1); }
  50%  { transform: translate(6vmax, 4vmax) scale(1.1); }
  100% { transform: translate(-4vmax, 8vmax) scale(0.95); }
}

/* ---------- Card ---------- */
.card {
  position: relative;
  width: 100%;
  max-width: 560px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 32px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  animation: rise 0.7s cubic-bezier(0.2, 0.8, 0.2, 1) both;
}
.card::before {
  /* gradient hairline border */
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, var(--accent), transparent 40%, transparent 60%, var(--accent-2));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(18px) scale(0.98); }
  to   { opacity: 1; transform: none; }
}

/* ---------- Nav ---------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px max(16px, calc((100vw - 1040px) / 2));
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}
.nav a { color: inherit; text-decoration: none; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: -0.02em; }
.logo {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 0.9rem;
  background: linear-gradient(135deg, var(--accent), var(--accent-3));
}
.nav-links { display: flex; align-items: center; gap: 20px; font-size: 0.9rem; }
.nav-links a:not(.nav-cta) { color: var(--muted); transition: color 0.2s; }
.nav-links a:not(.nav-cta):hover { color: var(--text); }
.nav-cta {
  padding: 7px 14px;
  border-radius: 10px;
  background: var(--text);
  color: var(--bg) !important;
  font-weight: 500;
}

/* ---------- Hero ---------- */
.hero { margin-bottom: 24px; }
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 500;
}
a.badge { text-decoration: none; transition: border-color 0.2s; }
a.badge:hover { border-color: color-mix(in srgb, var(--accent) 50%, transparent); }
.badge .tag {
  padding: 1px 8px;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.badge { padding-left: 4px; }

.features { display: flex; flex-wrap: wrap; gap: 8px 18px; list-style: none; margin: 16px 0 0; padding: 0; font-size: 0.88rem; color: var(--muted); }
.features li::before { content: "✓"; margin-right: 6px; color: var(--ok); font-weight: 700; }

h1 {
  margin: 14px 0 6px;
  font-size: clamp(1.8rem, 6vw, 2.5rem);
  line-height: 1.1;
  letter-spacing: -0.03em;
}
.grad {
  background: linear-gradient(90deg, var(--accent), var(--accent-3));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
@keyframes shimmer { to { background-position: 300% 0; } }

.sub { margin: 0; color: var(--muted); }

/* ---------- Panels & forms ---------- */
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 18px;
  margin-bottom: 16px;
}

label { display: block; font-weight: 500; margin-bottom: 8px; font-size: 0.9rem; color: var(--muted); }
.row { display: flex; gap: 8px; flex-wrap: wrap; }

input {
  flex: 1 1 160px;
  min-width: 0;
  padding: 11px 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--card);
  color: inherit;
  font: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
}
input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 22%, transparent);
}
input.short { flex: 0 1 130px; }

button {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 11px 18px;
  border: 0;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  background-size: 150% 150%;
  color: #fff;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 8px 20px -8px color-mix(in srgb, var(--accent) 70%, transparent);
  transition: transform 0.15s, box-shadow 0.2s, background-position 0.4s;
}
button:hover { transform: translateY(-1px); background-position: 100% 100%; box-shadow: 0 12px 24px -8px color-mix(in srgb, var(--accent-2) 70%, transparent); }
button:active { transform: translateY(1px) scale(0.98); }
button:focus-visible { outline: 3px solid color-mix(in srgb, var(--accent) 50%, transparent); outline-offset: 2px; }
button:disabled { opacity: 0.6; cursor: progress; transform: none; }
button:hover .wave { animation: wave 0.9s ease-in-out; }

@keyframes wave {
  0%, 100% { transform: rotate(0); }
  20% { transform: rotate(18deg); }
  40% { transform: rotate(-10deg); }
  60% { transform: rotate(14deg); }
  80% { transform: rotate(-4deg); }
}
.wave { display: inline-block; transform-origin: 70% 70%; }

/* ---------- Hello result ---------- */
output { display: block; min-height: 0; }
output:not(:empty) { margin-top: 14px; }
.greeting {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: 12px;
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  animation: pop 0.45s cubic-bezier(0.2, 1.4, 0.4, 1) both;
}
.greeting .emoji { font-size: 1.7rem; animation: wave 1.2s ease-in-out 0.2s; transform-origin: 70% 70%; }
.greeting strong { display: block; font-size: 1.1rem; }
.greeting small { color: var(--muted); }
.error { color: var(--bad); }

@keyframes pop {
  from { opacity: 0; transform: scale(0.9) translateY(6px); }
  to   { opacity: 1; transform: none; }
}

/* ---------- Guestbook ---------- */
.section-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
h2 { margin: 0; font-size: 1.15rem; letter-spacing: -0.01em; }
.chip {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 999px;
  color: var(--ok);
  background: color-mix(in srgb, var(--ok) 14%, transparent);
}

.counter { text-align: right; font-size: 0.75rem; color: var(--muted); margin-top: 6px; font-variant-numeric: tabular-nums; }
.counter.warn { color: var(--accent-2); }

.status { margin: 6px 0 0; font-size: 0.9rem; color: var(--muted); }
.status:empty { display: none; }

#messages { list-style: none; margin: 10px 0 0; padding: 0; display: grid; gap: 8px; }
#messages li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 12px;
  border-radius: 12px;
  background: var(--card);
  border: 1px solid var(--border);
  overflow-wrap: anywhere;
  animation: slideIn 0.4s ease both;
  animation-delay: calc(var(--i, 0) * 50ms);
  transition: transform 0.2s, border-color 0.2s;
}
#messages li:hover { transform: translateX(3px); border-color: color-mix(in srgb, var(--accent) 40%, transparent); }
#messages li.fresh { border-color: var(--accent-2); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent-2) 18%, transparent); }

.avatar {
  flex: none;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 0.9rem;
  color: #fff;
  background: linear-gradient(135deg, hsl(var(--h) 75% 58%), hsl(calc(var(--h) + 40) 75% 50%));
}
.msg-head { display: flex; gap: 8px; align-items: baseline; flex-wrap: wrap; }
.msg-head strong { font-size: 0.95rem; }
.msg-head time { font-size: 0.78rem; color: var(--muted); }
.msg-body { margin: 2px 0 0; }

.skeleton li { height: 62px; background: linear-gradient(90deg, var(--panel), color-mix(in srgb, var(--accent) 10%, transparent), var(--panel)) !important; background-size: 200% 100% !important; animation: shimmer-bg 1.2s linear infinite !important; }
@keyframes shimmer-bg { to { background-position: -200% 0; } }

@keyframes slideIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: none; }
}

/* ---------- Footer ---------- */
footer {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.85rem;
}
.muted { opacity: 0.8; }
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 2px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
}
.pill .pulse { width: 7px; height: 7px; border-radius: 50%; background: var(--muted); }
.pill.ok { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 40%, transparent); }
.pill.ok .pulse { background: var(--ok); animation: ping 2s infinite; }
.pill.bad { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 40%, transparent); }
.pill.bad .pulse { background: var(--bad); }

@keyframes ping {
  0%   { box-shadow: 0 0 0 0 color-mix(in srgb, var(--ok) 60%, transparent); }
  70%  { box-shadow: 0 0 0 7px transparent; }
  100% { box-shadow: 0 0 0 0 transparent; }
}

/* ---------- Confetti ---------- */
.confetti {
  position: fixed;
  top: 0;
  left: 0;
  width: 8px;
  height: 12px;
  border-radius: 2px;
  pointer-events: none;
  z-index: 10;
  animation: burst 1s cubic-bezier(0.1, 0.7, 0.3, 1) forwards;
}
@keyframes burst {
  to { transform: translate(var(--dx), var(--dy)) rotate(var(--r)); opacity: 0; }
}

/* ---------- Small screens & reduced motion ---------- */
@media (max-width: 480px) {
  .nav-links a:not(.nav-cta) { display: none; }
  .card { padding: 22px 18px; border-radius: 20px; }
  input.short { flex: 1 1 100%; }
  .row button { flex: 1 1 auto; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}