@import url("https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700&family=Sarabun:wght@300;400;600&display=swap");

:root {
  color-scheme: light dark;
  --bg-start: #0f172a;
  --bg-end: #1e3a8a;
  --card-bg: rgba(15, 23, 42, 0.78);
  --card-border: rgba(148, 163, 184, 0.35);
  --panel-bg: rgba(255, 255, 255, 0.86);
  --panel-border: rgba(15, 23, 42, 0.08);
  --accent: #38bdf8;
  --accent-strong: #0ea5e9;
  --accent-soft: rgba(56, 189, 248, 0.18);
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-inverse: #f8fafc;
  --error-bg: rgba(239, 68, 68, 0.16);
  --error-text: #b91c1c;
  --success-bg: rgba(34, 197, 94, 0.16);
  --shadow-soft: 0 24px 50px rgba(15, 23, 42, 0.3);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", "Sarabun", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: linear-gradient(160deg, var(--bg-start), var(--bg-end));
  color: var(--text-inverse);
  min-height: 100vh;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 48px 20px 80px;
  display: grid;
  gap: 36px;
}

.hero {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  align-items: stretch;
}

.hero-copy {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 24px;
  padding: 36px;
  backdrop-filter: blur(14px);
  box-shadow: var(--shadow-soft);
}

.hero-copy .eyebrow {
  letter-spacing: 0.2em;
  text-transform: uppercase;
  font-size: 0.75rem;
  color: rgba(148, 163, 184, 0.8);
  margin: 0 0 12px;
}

.hero-copy h1 {
  font-size: clamp(1.9rem, 3vw, 2.8rem);
  margin: 0 0 18px;
  line-height: 1.25;
}

.hero-copy h1 span {
  display: block;
  font-size: clamp(1rem, 2.4vw, 1.2rem);
  font-weight: 400;
  color: rgba(240, 249, 255, 0.8);
  margin-top: 6px;
}

.hero-copy p {
  margin: 0;
  line-height: 1.6;
  color: rgba(226, 232, 240, 0.85);
  display: grid;
  gap: 4px;
}

.hero-card {
  background: var(--panel-bg);
  color: var(--text-primary);
  border-radius: 24px;
  border: 1px solid var(--panel-border);
  padding: 28px;
  display: grid;
  gap: 18px;
  box-shadow: 0 15px 35px rgba(15, 23, 42, 0.18);
}

.hero-card h2 {
  margin: 0;
  font-size: 1.6rem;
  color: var(--text-primary);
}

section.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.card {
  background: rgba(255, 255, 255, 0.92);
  border-radius: 24px;
  padding: 28px;
  border: 1px solid rgba(15, 23, 42, 0.08);
  box-shadow: 0 20px 45px rgba(15, 23, 42, 0.12);
  color: var(--text-secondary);
}

.card h3 {
  color: var(--text-primary);
  font-size: 1.5rem;
  margin: 0 0 12px;
}

.card-intro {
  margin: 0 0 16px;
  display: grid;
  gap: 4px;
}

label {
  display: block;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

input[type="text"],
textarea {
  width: 100%;
  padding: 14px 16px;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.3);
  background: rgba(255, 255, 255, 0.92);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border 0.2s ease, box-shadow 0.2s ease;
}

input[type="text"]:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

textarea {
  min-height: 200px;
  resize: vertical;
}

.button-row {
  margin-top: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 20px;
  border-radius: 14px;
  border: none;
  font-weight: 600;
  cursor: pointer;
  font-size: 1rem;
  background: linear-gradient(160deg, var(--accent), var(--accent-strong));
  color: white;
  transition: transform 0.18s ease, box-shadow 0.2s ease;
  box-shadow: 0 12px 24px rgba(14, 165, 233, 0.25);
}

button:hover {
  transform: translateY(-1px);
}

button.secondary {
  background: rgba(15, 23, 42, 0.04);
  color: var(--text-primary);
  border: 1px solid rgba(148, 163, 184, 0.35);
  box-shadow: none;
}

.result,
.error {
  margin-top: 18px;
  padding: 16px 18px;
  border-radius: 16px;
  border: 1px solid transparent;
  line-height: 1.6;
}

.result {
  background: var(--success-bg);
  border-color: rgba(34, 197, 94, 0.4);
  color: #0f5132;
}

.error {
  background: var(--error-bg);
  border-color: rgba(239, 68, 68, 0.3);
  color: var(--error-text);
}

.result-card {
  background: rgba(241, 245, 249, 0.9);
  border-radius: 24px;
  padding: 24px;
  border: 1px solid rgba(148, 163, 184, 0.3);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.18);
  display: grid;
  gap: 16px;
}

.result-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.code-pill {
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--text-primary);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.copy-chip {
  border: 1px solid rgba(30, 64, 175, 0.2);
  background: rgba(30, 64, 175, 0.08);
  color: #1e40af;
  border-radius: 12px;
  padding: 6px 14px;
  font-weight: 600;
  cursor: pointer;
}

.copy-chip:hover {
  background: rgba(30, 64, 175, 0.16);
}

.copy-success {
  padding: 12px 14px;
  background: rgba(56, 189, 248, 0.18);
  border-radius: 12px;
  border: 1px solid rgba(56, 189, 248, 0.35);
  color: #0c4a6e;
}

.result-meta {
  display: grid;
  gap: 4px;
  color: var(--text-secondary);
}

.result-meta strong {
  color: var(--text-primary);
}

.remaining {
  font-weight: 600;
  color: #1d4ed8;
}

.qr-block {
  display: grid;
  place-items: center;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.qr-inline {
  display: inline-block;
}

.qr-wrapper {
  position: relative;
  display: inline-block;
}

.qr-wrapper img.qr {
  width: 160px;
  height: 160px;
  border-radius: 16px;
}

.qr-wrapper img.logo {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 46px;
  height: 46px;
  border-radius: 12px;
  background: #fff;
  padding: 6px;
  box-shadow: 0 6px 18px rgba(15, 23, 42, 0.18);
}

.link-text {
  word-break: break-all;
}

@media (max-width: 720px) {
  main {
    padding: 32px 16px 60px;
  }

  .hero-card,
  .card {
    padding: 24px;
  }

  .button-row {
    width: 100%;
  }

  button,
  button.secondary {
    flex: 1 1 100%;
  }
}