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

[hidden] { display: none; }

:root {
  --accent: #1FA67D;
  --accent-dark: #12A0A0;
  --accent-blue: #1C7FB8;
  --text: #0E2A30;
  --muted: rgba(14, 42, 48, 0.55);
  --bg: #ffffff;
  --bg-alt: #EEF3F2;
  --border: rgba(14, 42, 48, 0.12);
  --radius: 8px;
  --max-width: 960px;
}

body {
  font-family: system-ui, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

/* nav */
nav {
  position: sticky;
  top: 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  z-index: 100;
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  height: 32px;
  width: auto;
  display: block;
}

/* sections */
section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem 2rem;
}

section h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  text-align: center;
}

/* hero */
#hero {
  text-align: center;
  padding-top: 2.5rem;
  padding-bottom: 1.5rem;
}

#hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
}

.subtitle {
  font-size: 1.2rem;
  color: var(--muted);
  max-width: 580px;
  margin: 0 auto;
}

/* button */
.btn-primary {
  display: inline-block;
  background: #1C7FB8;
  color: #fff;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.15s;
}

.btn-primary:hover {
  background: #0E2A30;
}

/* steps */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.step {
  text-align: center;
  padding: 1rem;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.step h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.step p {
  color: var(--muted);
  font-size: 0.9rem;
}

/* shared panel toggle button */
.text-btn {
  display: block;
  width: fit-content;
  margin: 1.25rem auto 0;
  background: none;
  border: none;
  color: var(--accent);
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  padding: 0;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.text-btn:hover {
  color: var(--accent-dark);
}

/* transcript */
.transcript-content .speaker {
  color: var(--accent);
  font-weight: 600;
}

.transcript-content {
  margin-top: 1rem;
  padding: 1rem 1.25rem;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-align: left;
  font-size: 0.9rem;
  line-height: 1.8;
  white-space: pre-wrap;
  color: var(--text);
}


.how-it-works-detail {
  border-top: 1px solid var(--border);
  margin-top: 1.5rem;
  padding-top: 0.5rem;
}

/* under the hood */
#under-the-hood {
  background: var(--bg-alt);
  max-width: 100%;
  padding: 1.5rem 2rem;
}

#under-the-hood > h2 {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
}

.features {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(400px, 100%), 1fr));
  gap: 2rem;
}

.feature {
  padding: 1.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.feature h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.6rem;
}

.feature p {
  color: var(--muted);
  font-size: 0.95rem;
}

/* use cases section */
#use-cases {
  background: var(--bg-alt);
  max-width: 100%;
  padding: 1.5rem 2rem;
}

#use-cases > h2 {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 0.5rem;
}

#use-cases > .section-intro {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 1.75rem;
  text-align: center;
  color: var(--muted);
}

/* use case tabs */
.use-case-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
  justify-content: center;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
}

.tab-btn {
  padding: 0.55rem 1.2rem;
  border: 1px solid var(--border);
  background: var(--bg);
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.9rem;
  font-family: inherit;
  color: var(--muted);
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  white-space: nowrap;
}

.tab-btn.active {
  background: #1C7FB8;
  color: #fff;
  border-color: #1C7FB8;
}

.tab-btn:hover:not(.active) {
  border-color: #1C7FB8;
  color: #1C7FB8;
}

/* use case panels */
.use-case-panel {
  display: none;
  text-align: center;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.use-case-panel.active {
  display: block;
}

.use-case-panel h3 {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.use-case-panel p {
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 1.75rem;
}

.use-case-panel audio {
  width: 100%;
  max-width: 400px;
}


/* contact */
#contact {
  max-width: 560px;
  text-align: center;
}

#contact p {
  color: var(--muted);
  margin-bottom: 2rem;
}

form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  text-align: left;
}

form input,
form textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 1rem;
  font-family: inherit;
  color: var(--text);
  background: var(--bg);
}

form input:focus,
form textarea:focus {
  outline: 2px solid var(--accent);
  border-color: transparent;
}

form button {
  align-self: center;
}

/* form banners */
.success-banner {
  background: rgba(31, 166, 125, 0.1);
  color: #1FA67D;
  border: 1px solid rgba(31, 166, 125, 0.3);
  border-radius: var(--radius);
  padding: 0.85rem 1.25rem;
  font-weight: 500;
  margin-bottom: 2.5rem;
}

.error-banner {
  background: #0E2A30;
  color: #EEF3F2;
  border: 1px solid #0E2A30;
  border-radius: var(--radius);
  padding: 0.85rem 1.25rem;
  font-weight: 500;
  margin-bottom: 2.5rem;
}

/* footer */
footer {
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 2rem;
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 480px) {
  .use-case-panel {
    padding: 1.5rem 1rem;
  }
}