:root {
  --sky: #e4eff6;
  --ink: #12324a;
  --ink-soft: #46647a;
  --kite: #f4c430;
  --kite-deep: #d9a400;
  --line: #a9c3d6;
  --card: #ffffff;
  --danger: #b3261e;
  --radius-lg: 18px;
  --radius-sm: 10px;
  --step--1: 0.875rem;
  --step-0: 1rem;
  --step-1: 1.25rem;
  --step-2: 1.6rem;
  --step-3: clamp(2rem, 6vw, 3rem);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --sky: #0d2232;
    --ink: #e8f1f7;
    --ink-soft: #a5bccd;
    --line: #2d4b61;
    --card: #142d40;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--sky);
  color: var(--ink);
  font-family: "Be Vietnam Pro", system-ui, sans-serif;
  font-size: var(--step-0);
  line-height: 1.6;
}
a { color: inherit; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible {
  outline: 3px solid var(--kite-deep);
  outline-offset: 2px;
}
.wrap { max-width: 720px; margin: 0 auto; padding: 0 16px; }

/* header */
.top { display: flex; align-items: center; justify-content: space-between; padding: 18px 0; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: var(--step-1); text-decoration: none; }
.brand svg { width: 28px; height: 28px; }
.lang { font-size: var(--step--1); color: var(--ink-soft); }
.lang a[aria-current="page"] { color: var(--ink); font-weight: 600; text-decoration: none; }

/* hero */
.hero { position: relative; padding: 40px 0 8px; }
.hero h1 {
  font-size: var(--step-3); line-height: 1.1; letter-spacing: -0.02em;
  margin: 0 0 12px; max-width: 14ch; font-weight: 800;
}
.hero p { margin: 0 0 28px; color: var(--ink-soft); max-width: 46ch; }
.kite {
  position: absolute; right: 4px; top: 8px; width: 110px; height: 230px;
  pointer-events: none; transform-origin: 60% 15%;
}
@media (prefers-reduced-motion: no-preference) {
  .kite { animation: sway 5s ease-in-out infinite; }
  @keyframes sway { 0%,100% { transform: rotate(-4deg); } 50% { transform: rotate(5deg); } }
}


/* form */
.paste {
  position: relative; display: flex; gap: 8px; padding: 8px;
  background: var(--card); border: 2px solid var(--ink); border-radius: var(--radius-lg);
}
.paste input {
  flex: 1; min-width: 0; border: 0; background: transparent; color: var(--ink);
  font: inherit; font-size: var(--step-0); padding: 12px 10px;
}
.paste input::placeholder { color: var(--ink-soft); }
.btn {
  border: 0; border-radius: var(--radius-sm); font: inherit; font-weight: 700; cursor: pointer;
  padding: 12px 20px; background: var(--kite); color: #12324a; white-space: nowrap;
}
.btn:hover { background: var(--kite-deep); }
.btn[disabled] { opacity: .6; cursor: progress; }
.btn-ghost { background: transparent; color: var(--ink); border: 1.5px solid var(--line); }
.btn-ghost:hover { background: var(--card); }
.note { font-size: var(--step--1); color: var(--ink-soft); margin: 12px 4px 0; }
.result .note { margin: 10px 0 8px; }
.status { min-height: 1.6em; margin: 14px 4px 0; font-weight: 500; }
.status.error { color: var(--danger); }
#captcha { margin-top: 12px; }

/* result */
.result { margin-top: 20px; padding-bottom: 4px; background: var(--card); border-radius: var(--radius-lg); padding: 16px; border: 1px solid var(--line); }
.result[hidden] { display: none; }
.meta { display: flex; gap: 14px; align-items: flex-start; }
.meta img { width: 84px; height: 112px; object-fit: cover; border-radius: var(--radius-sm); background: var(--sky); flex: none; }
.meta h2 { font-size: var(--step-0); margin: 0 0 4px; font-weight: 600; overflow-wrap: anywhere; }
.meta .by { font-size: var(--step--1); color: var(--ink-soft); }
.options { list-style: none; padding: 0; margin: 16px 0 0; display: grid; gap: 8px; }
.options a {
  display: flex; justify-content: space-between; align-items: center; gap: 12px; text-decoration: none;
  padding: 12px 14px; border-radius: var(--radius-sm); border: 1.5px solid var(--line); font-weight: 600;
}
.options a:hover { border-color: var(--ink); }
.options .size { font-weight: 400; color: var(--ink-soft); font-size: var(--step--1); }
.options li:first-child a { background: var(--kite); border-color: var(--kite); color: #12324a; }
.options li:first-child .size { color: #12324a; }

/* sections */
section.block { padding: 48px 0 0; }
section.block h2 { font-size: var(--step-2); margin: 0 0 16px; letter-spacing: -0.01em; }
.steps { margin: 0; padding-left: 1.4em; display: grid; gap: 10px; }
.steps li::marker { font-weight: 700; }
.platforms { display: flex; flex-wrap: wrap; gap: 8px; padding: 0; list-style: none; margin: 0; }
.platforms li { padding: 6px 14px; border: 1.5px solid var(--line); border-radius: 999px; font-weight: 500; }
details { border-top: 1px solid var(--line); padding: 14px 0; }
details:last-of-type { border-bottom: 1px solid var(--line); }
summary { cursor: pointer; font-weight: 600; }
details p { margin: 8px 0 0; color: var(--ink-soft); }

/* legal pages */
.legal { padding: 24px 0 0; max-width: 68ch; }
.legal h1 { font-size: var(--step-2); }
.legal h2 { font-size: var(--step-1); margin-top: 28px; }

footer { margin: 64px 0 0; padding: 24px 0 40px; border-top: 1px solid var(--line); font-size: var(--step--1); color: var(--ink-soft); }
footer nav { display: flex; flex-wrap: wrap; gap: 16px; margin-bottom: 8px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }

/* mobile: đặt cuối file để thắng các rule ở trên */
@media (max-width: 560px) {
  .kite { width: 64px; height: 134px; top: 18px; }
  .hero h1 { max-width: 10ch; }
  .hero p { padding-right: 56px; }
  .paste { flex-wrap: wrap; }
  .paste input { flex-basis: 100%; }
  .paste .btn { flex: 1; }
}