:root {
  --abyss: #030b14;
  --deep-blue: #07182b;
  --panel: rgba(7, 24, 43, 0.82);
  --glow: #4dd9e8;
  --glow-soft: rgba(77, 217, 232, 0.35);
  --text: #d9eef5;
  --text-dim: #8fb3c2;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Avenir Next", "Segoe UI", system-ui, sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, var(--deep-blue) 0%, var(--abyss) 70%);
}

#ocean {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

main {
  position: relative;
  z-index: 1;
  max-width: 720px;
  margin: 0 auto;
  padding: 3rem 1.25rem 4rem;
  display: grid;
  gap: 1.5rem;
}

header {
  text-align: center;
}

.badge {
  display: inline-block;
  padding: 0.3rem 0.9rem;
  border: 1px solid var(--glow-soft);
  border-radius: 999px;
  color: var(--glow);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

h1 {
  margin: 0.75rem 0 0.25rem;
  font-size: clamp(2.2rem, 6vw, 3.4rem);
  letter-spacing: 0.02em;
  text-shadow: 0 0 24px var(--glow-soft);
}

.subtitle {
  margin: 0;
  color: var(--text-dim);
}

.fact-card,
.chat-card {
  background: var(--panel);
  border: 1px solid rgba(77, 217, 232, 0.18);
  border-radius: 16px;
  padding: 1.5rem;
  backdrop-filter: blur(6px);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.45);
}

h2 {
  margin: 0 0 0.75rem;
  font-size: 1.1rem;
  color: var(--glow);
  letter-spacing: 0.04em;
}

#fact-text {
  min-height: 3.2rem;
  margin: 0 0 1rem;
  font-size: 1.15rem;
  line-height: 1.55;
}

.fact-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

#fact-counter {
  color: var(--text-dim);
  font-size: 0.85rem;
}

button {
  font: inherit;
  padding: 0.55rem 1.2rem;
  border: 1px solid var(--glow-soft);
  border-radius: 10px;
  background: transparent;
  color: var(--glow);
  cursor: pointer;
  transition:
    background 150ms ease,
    transform 150ms ease;
}

button:hover {
  background: rgba(77, 217, 232, 0.12);
  transform: translateY(-1px);
}

.chat-hint {
  margin: 0 0 1rem;
  color: var(--text-dim);
  font-size: 0.9rem;
}

#chat-log {
  display: grid;
  gap: 0.6rem;
  max-height: 320px;
  overflow-y: auto;
  margin-bottom: 1rem;
}

#chat-log:empty {
  display: none;
}

.message {
  padding: 0.6rem 0.9rem;
  border-radius: 12px;
  line-height: 1.5;
  max-width: 90%;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.message.user {
  justify-self: end;
  background: rgba(77, 217, 232, 0.16);
}

.message.sonar {
  justify-self: start;
  background: rgba(255, 255, 255, 0.06);
}

.message.error {
  justify-self: start;
  background: rgba(232, 110, 77, 0.16);
  color: #f2c4b3;
}

#chat-form {
  display: flex;
  gap: 0.6rem;
}

#chat-input {
  flex: 1;
  font: inherit;
  padding: 0.55rem 0.9rem;
  border: 1px solid rgba(77, 217, 232, 0.25);
  border-radius: 10px;
  background: rgba(3, 11, 20, 0.6);
  color: var(--text);
}

#chat-input:focus {
  outline: 2px solid var(--glow-soft);
}

footer {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.9rem;
}

footer a {
  color: var(--glow);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (prefers-reduced-motion: reduce) {
  button {
    transition: none;
  }
}