:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #172033;
  --muted: #667085;
  --border: #d0d5dd;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
}

main {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px 16px;
}

.container {
  width: 100%;
  max-width: 680px;
  text-align: center;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(32px, 6vw, 52px);
  line-height: 1.05;
}

.subtitle {
  margin: 0 auto 32px;
  max-width: 520px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.5;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 24px;
  box-shadow: 0 20px 50px rgba(23, 32, 51, 0.08);
}

form {
  display: grid;
  gap: 18px;
}

.upload-box {
  border: 2px dashed var(--border);
  border-radius: 18px;
  padding: 32px 18px;
  background: #fafbff;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.upload-box.dragover {
  border-color: var(--primary);
  background: #eef4ff;
}

.upload-box strong {
  display: block;
  margin-bottom: 8px;
  font-size: 18px;
}

.upload-box span {
  display: block;
  color: var(--muted);
  font-size: 14px;
}

.support-text {
  display: block;
  margin-top: 10px;
  color: var(--muted);
  font-size: 13px;
}

.upload-box input {
  display: none;
}

.row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  text-align: left;
}

label {
  font-weight: 600;
}

select,
button {
  width: 100%;
  border-radius: 12px;
  font-size: 16px;
  padding: 14px 16px;
}

select {
  margin-top: 8px;
  border: 1px solid var(--border);
  background: white;
  color: var(--text);
}

button {
  border: 0;
  background: var(--primary);
  color: white;
  font-weight: 700;
  cursor: pointer;
}

button:hover {
  background: var(--primary-dark);
}

.features {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 20px;
  color: var(--muted);
  font-size: 14px;
}

.feature {
  background: rgba(255, 255, 255, 0.65);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
}

.popular-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px 12px;
  margin-top: 14px;
  color: var(--muted);
  font-size: 13px;
}

.popular-links a {
  color: var(--muted);
  text-decoration: none;
}

.popular-links a:hover {
  color: var(--primary);
  text-decoration: underline;
}

@media (min-width: 640px) {
  .row {
    grid-template-columns: 1fr 1fr;
    align-items: end;
  }

  .features {
    grid-template-columns: repeat(3, 1fr);
  }
}