/* ==========================================================================
   Hunan Studio — design system
   Two-tone: deep navy base + amber accent. Serif headlines, small-caps
   labels, hairline dividers, inline SVG icons. No emoji, no stock art.
   ========================================================================== */

:root {
  --bg: #0a0e17;
  --bg-2: #0e1421;
  --surface: #121a2b;
  --surface-2: #172033;
  --line: rgba(255, 255, 255, 0.09);
  --line-strong: rgba(255, 255, 255, 0.18);
  --ink: #eef1f7;
  --ink-2: #b3bcd0;
  --ink-3: #7d879c;
  --accent: #f0b429;
  --accent-dim: rgba(240, 180, 41, 0.14);
  --accent-line: rgba(240, 180, 41, 0.42);
  --ok: #4ade80;
  --err: #f87171;
  --serif: "Instrument Serif", "Iowan Old Style", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --wrap: 1180px;
  --radius: 14px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 28px; }

/* ---------- type ---------- */
h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: -0.015em;
  margin: 0;
}

h1 { font-size: clamp(2.6rem, 6vw, 4.6rem); }
h2 { font-size: clamp(2rem, 3.6vw, 2.9rem); }
h3 { font-size: 1.32rem; }
h4 { font-size: 1.06rem; }

p { margin: 0; color: var(--ink-2); }

.label {
  font-size: 0.68rem;
  letter-spacing: 0.19em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  font-family: var(--sans);
}

.muted { color: var(--ink-3); }

.hairline { height: 1px; background: var(--line); border: 0; margin: 0; }

/* ---------- nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(10, 14, 23, 0.86);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.nav-inner {
  display: flex;
  align-items: center;
  gap: 30px;
  height: 66px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--serif);
  font-size: 1.22rem;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.brand svg { width: 24px; height: 24px; flex: none; }

.brand .uno {
  font-family: var(--sans);
  font-size: 0.56rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-3);
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  padding: 2px 6px;
  font-weight: 600;
}

.nav-links { display: flex; align-items: center; gap: 4px; margin-left: auto; }

.nav-links > a, .nav-links .drop-btn {
  padding: 8px 13px;
  font-size: 0.87rem;
  color: var(--ink-2);
  border: 0;
  background: none;
  border-radius: 8px;
  transition: color 0.16s, background 0.16s;
  white-space: nowrap;
}

.nav-links > a:hover, .nav-links .drop-btn:hover { color: var(--ink); background: rgba(255,255,255,0.05); }

.nav-links .has-drop { position: relative; }
.drop-btn { display: inline-flex; align-items: center; gap: 6px; }
.drop-btn svg { width: 11px; height: 11px; opacity: 0.6; }

.drop-menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  min-width: 230px;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  padding: 6px;
  box-shadow: 0 20px 44px rgba(0, 0, 0, 0.55);
  display: none;
}

.has-drop:hover .drop-menu, .has-drop.open .drop-menu { display: block; }

.drop-menu a {
  display: block;
  padding: 9px 12px;
  font-size: 0.86rem;
  color: var(--ink-2);
  border-radius: 7px;
}

.drop-menu a:hover { background: rgba(255,255,255,0.06); color: var(--ink); }
.drop-menu a span { display: block; font-size: 0.72rem; color: var(--ink-3); }

.btn-nav {
  padding: 8px 16px !important;
  border-radius: 8px !important;
  background: var(--accent) !important;
  color: #1a1204 !important;
  font-weight: 600;
}

.btn-nav:hover { filter: brightness(1.08); background: var(--accent) !important; color: #1a1204 !important; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 13px 26px;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  border: 1px solid transparent;
  transition: transform 0.14s, filter 0.14s, background 0.14s, border-color 0.14s;
}

.btn svg { width: 16px; height: 16px; }
.btn-primary { background: var(--accent); color: #1a1204; }
.btn-primary:hover { filter: brightness(1.08); transform: translateY(-1px); }
.btn-ghost { border-color: var(--line-strong); color: var(--ink); background: transparent; }
.btn-ghost:hover { border-color: var(--accent-line); background: var(--accent-dim); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; transform: none; filter: none; }

/* ---------- hero ---------- */
.hero { padding: 92px 0 80px; position: relative; overflow: hidden; }

.hero::before {
  content: "";
  position: absolute;
  top: -240px;
  right: -140px;
  width: 720px;
  height: 720px;
  background: radial-gradient(circle, rgba(240,180,41,0.09), transparent 66%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.06fr 0.94fr;
  gap: 62px;
  align-items: center;
  position: relative;
}

.hero h1 { margin: 18px 0 0; }
.hero h1 em { font-style: normal; color: var(--accent); }

.hero-lede { font-size: 1.1rem; margin-top: 20px; max-width: 46ch; }

.hero-cta { display: flex; gap: 12px; margin-top: 32px; flex-wrap: wrap; }

.hero-note {
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 0.8rem;
  color: var(--ink-3);
  max-width: 52ch;
}

/* prompt preview card */
.prompt-card {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: 0 26px 60px rgba(0, 0, 0, 0.45);
}

.prompt-card .pc-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.prompt-card textarea {
  width: 100%;
  min-height: 108px;
  resize: vertical;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 0.93rem;
  line-height: 1.6;
  padding: 14px;
}

.prompt-card textarea:focus { outline: none; border-color: var(--accent-line); }

.chips { display: flex; gap: 7px; flex-wrap: wrap; margin-top: 13px; }

.chip {
  font-size: 0.74rem;
  padding: 5px 11px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  color: var(--ink-2);
  background: transparent;
  transition: all 0.15s;
}

.chip:hover { border-color: var(--accent-line); color: var(--accent); background: var(--accent-dim); }

/* ---------- sections ---------- */
section { padding: 84px 0; }
.section-alt { background: var(--bg-2); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }

.sec-head { max-width: 660px; margin-bottom: 52px; }
.sec-head h2 { margin-top: 14px; }
.sec-head p { margin-top: 15px; font-size: 1.02rem; }

/* ---------- feature grid ---------- */
.f-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }

.f-card { background: var(--bg); padding: 34px 28px; transition: background 0.2s; }
.section-alt .f-card { background: var(--bg-2); }
.f-card:hover { background: var(--surface); }

.f-ico {
  width: 40px;
  height: 40px;
  border-radius: 9px;
  border: 1px solid var(--accent-line);
  background: var(--accent-dim);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}

.f-ico svg { width: 20px; height: 20px; stroke: var(--accent); fill: none; stroke-width: 1.5; }
.f-card h3 { margin-bottom: 9px; }
.f-card p { font-size: 0.92rem; }

/* ---------- stats ---------- */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border-block: 1px solid var(--line); }

.stat { background: var(--bg); padding: 52px 28px; text-align: center; }
.stat-v { font-family: var(--serif); font-size: clamp(2.4rem, 5vw, 3.6rem); color: var(--accent); line-height: 1; }
.stat-l { margin-top: 14px; font-size: 0.88rem; color: var(--ink-3); }

/* ---------- sound strip ---------- */
.sound-list { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-top: 34px; }

.sound-item {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 18px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg);
  transition: border-color 0.18s;
}

.sound-item:hover { border-color: var(--accent-line); }
.sound-item svg { width: 19px; height: 19px; stroke: var(--accent); fill: none; stroke-width: 1.5; flex: none; }
.sound-item span { font-size: 0.87rem; color: var(--ink-2); }

/* ---------- use-case list ---------- */
.uc-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }

.uc-card { border-top: 2px solid var(--accent-line); padding-top: 22px; }
.uc-card h3 { margin-bottom: 11px; }
.uc-card p { font-size: 0.9rem; margin-bottom: 15px; }
.ticks { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.ticks li { display: flex; align-items: center; gap: 9px; font-size: 0.86rem; color: var(--ink-2); }
.ticks svg { width: 13px; height: 13px; stroke: var(--accent); fill: none; stroke-width: 2; flex: none; }

/* ---------- faq ---------- */
.faq-list { border-top: 1px solid var(--line); max-width: 800px; }

.faq-item { border-bottom: 1px solid var(--line); }
.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: 0;
  padding: 24px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.16rem;
}

.faq-q svg { width: 16px; height: 16px; stroke: var(--accent); fill: none; stroke-width: 1.6; flex: none; transition: transform 0.22s; }
.faq-item.open .faq-q svg { transform: rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height 0.28s ease; }
.faq-a p { padding-bottom: 24px; font-size: 0.95rem; max-width: 70ch; }

/* ---------- cta ---------- */
.cta {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: 18px;
  padding: 66px 48px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta::after {
  content: "";
  position: absolute;
  bottom: -190px;
  left: 50%;
  transform: translateX(-50%);
  width: 560px;
  height: 380px;
  background: radial-gradient(ellipse at center, rgba(240,180,41,0.13), transparent 68%);
  pointer-events: none;
}

.cta h2 { margin: 14px 0 14px; }
.cta p { max-width: 54ch; margin: 0 auto; }
.cta .hero-cta { justify-content: center; position: relative; z-index: 1; }

/* ---------- footer ---------- */
footer { border-top: 1px solid var(--line); padding: 56px 0 34px; margin-top: 30px; }
.foot-grid { display: grid; grid-template-columns: 1.6fr repeat(3, 1fr); gap: 40px; }
.foot-grid h4 { font-family: var(--sans); font-size: 0.7rem; letter-spacing: 0.17em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 16px; font-weight: 600; }
.foot-grid ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.foot-grid a { font-size: 0.87rem; color: var(--ink-2); }
.foot-grid a:hover { color: var(--accent); }
.foot-about p { font-size: 0.87rem; margin-top: 14px; max-width: 40ch; }
.foot-bottom { margin-top: 44px; padding-top: 24px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: 0.8rem; color: var(--ink-3); }

/* ---------- studio ---------- */
.studio-shell { padding: 56px 0 90px; }

.studio-grid { display: grid; grid-template-columns: 400px 1fr; gap: 34px; align-items: start; }

.panel {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 26px;
  position: sticky;
  top: 88px;
}

.mode-tabs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; background: var(--bg-2); padding: 5px; border-radius: 10px; margin-bottom: 24px; border: 1px solid var(--line); }

.mode-tab {
  padding: 9px 6px;
  border: 0;
  background: none;
  border-radius: 7px;
  font-size: 0.79rem;
  font-weight: 600;
  color: var(--ink-3);
  transition: all 0.16s;
}

.mode-tab:hover { color: var(--ink); }
.mode-tab.active { background: var(--accent); color: #1a1204; }

.fld { margin-bottom: 19px; }
.fld label { display: block; font-size: 0.71rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 8px; font-weight: 600; }

.fld textarea, .fld input[type="text"], .fld select {
  width: 100%;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 9px;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 0.9rem;
  padding: 11px 13px;
}

.fld textarea { min-height: 116px; resize: vertical; line-height: 1.6; }
.fld textarea:focus, .fld input:focus, .fld select:focus { outline: none; border-color: var(--accent-line); }
.fld select { appearance: none; background-image: linear-gradient(45deg, transparent 50%, var(--ink-3) 50%), linear-gradient(135deg, var(--ink-3) 50%, transparent 50%); background-position: calc(100% - 18px) 50%, calc(100% - 13px) 50%; background-size: 5px 5px, 5px 5px; background-repeat: no-repeat; padding-right: 34px; }

.fld-row { display: grid; grid-template-columns: 1fr 1fr; gap: 13px; }

.hint { font-size: 0.76rem; color: var(--ink-3); margin-top: 7px; }

.drop-zone {
  border: 1.5px dashed var(--line-strong);
  border-radius: 10px;
  padding: 24px 16px;
  text-align: center;
  cursor: pointer;
  transition: all 0.18s;
  background: var(--bg-2);
}

.drop-zone:hover, .drop-zone.over { border-color: var(--accent-line); background: var(--accent-dim); }
.drop-zone svg { width: 26px; height: 26px; stroke: var(--ink-3); fill: none; stroke-width: 1.4; margin: 0 auto 10px; }
.drop-zone p { font-size: 0.82rem; }
.preview-img { width: 100%; border-radius: 9px; margin-bottom: 10px; }

.gen-btn { width: 100%; margin-top: 6px; }

/* output pane */
.output {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 26px;
  min-height: 460px;
}

.out-empty { display: flex; flex-direction: column; align-items: center; justify-content: center; height: 400px; text-align: center; color: var(--ink-3); }
.out-empty svg { width: 42px; height: 42px; stroke: var(--ink-3); fill: none; stroke-width: 1.2; margin-bottom: 18px; opacity: 0.7; }
.out-empty p { font-size: 0.9rem; max-width: 40ch; }

.status-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  margin-bottom: 20px;
  font-size: 0.88rem;
}

.spinner {
  width: 16px;
  height: 16px;
  border: 2px solid var(--line-strong);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  flex: none;
}

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

.result-img, .result-vid { width: 100%; border-radius: 11px; border: 1px solid var(--line); background: #000; }
.result-vid { max-height: 620px; }

.out-actions { display: flex; gap: 11px; margin-top: 18px; flex-wrap: wrap; }

.err-box {
  padding: 14px 18px;
  background: rgba(248, 113, 113, 0.09);
  border: 1px solid rgba(248, 113, 113, 0.35);
  border-radius: 10px;
  color: #fca5a5;
  font-size: 0.88rem;
  margin-bottom: 18px;
}

.ok-box {
  padding: 14px 18px;
  background: rgba(74, 222, 128, 0.08);
  border: 1px solid rgba(74, 222, 128, 0.3);
  border-radius: 10px;
  color: #86efac;
  font-size: 0.88rem;
  margin-bottom: 18px;
}

.gallery { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 13px; margin-top: 22px; }
.gallery figure { margin: 0; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; background: var(--bg-2); }
.gallery img { width: 100%; aspect-ratio: 16/9; object-fit: cover; }
.gallery figcaption { padding: 9px 11px; font-size: 0.74rem; color: var(--ink-3); }

/* ---------- responsive ---------- */
@media (max-width: 1000px) {
  .hero-grid { grid-template-columns: 1fr; gap: 44px; }
  .f-grid { grid-template-columns: repeat(2, 1fr); }
  .uc-grid { grid-template-columns: 1fr; gap: 34px; }
  .studio-grid { grid-template-columns: 1fr; }
  .panel { position: static; }
  .foot-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .sound-list { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 720px) {
  .wrap { padding: 0 18px; }
  section { padding: 60px 0; }
  .f-grid { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr; }
  .nav-links .hide-sm { display: none; }
  .foot-grid { grid-template-columns: 1fr; }
  .cta { padding: 46px 22px; }
  .fld-row { grid-template-columns: 1fr; }
  .mode-tabs { grid-template-columns: 1fr; }
  .sound-list { grid-template-columns: 1fr; }
  .hero { padding: 60px 0 54px; }
}