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

:root {
  --bg-gradient-1: #020617;
  --bg-gradient-2: #0f172a;
  --accent: #6366f1;
  --accent-soft: rgba(99, 102, 241, 0.4);
  --text-main: #f9fafb;
  --text-muted: #9ca3af;
  --glass-bg: rgba(15, 23, 42, 0.72);
  --glass-border: rgba(148, 163, 184, 0.35);
  --radius-lg: 24px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --shadow-soft: 0 24px 60px rgba(15, 23, 42, 0.75);
  --transition-fast: 160ms ease-out;
}

html,
body {
  height: 100%;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Segoe UI", sans-serif;
  color: var(--text-main);
  background: radial-gradient(circle at top left, var(--bg-gradient-2), #020617)
    fixed;
  overflow-x: hidden;
}

/* Background decoration */
.background-gradient {
  position: fixed;
  inset: 0;
  background:
    radial-gradient(circle at 10% 10%, rgba(56, 189, 248, 0.12), transparent),
    radial-gradient(circle at 90% 10%, rgba(129, 140, 248, 0.16), transparent),
    radial-gradient(circle at 10% 90%, rgba(45, 212, 191, 0.1), transparent),
    radial-gradient(circle at 90% 90%, rgba(251, 113, 133, 0.1), transparent);
  pointer-events: none;
  z-index: -2;
}

/* Layout */
.app {
  min-height: 100vh;
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 20px 40px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.app-header {
  text-align: center;
  margin-bottom: 8px;
}

.app-header h1 {
  font-size: clamp(1.9rem, 2.4vw, 2.4rem);
  letter-spacing: 0.04em;
  margin-bottom: 8px;
}

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

.app-footer {
  margin-top: 12px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* Glass card */
.card {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: 32px;
  padding: 28px;
  border-radius: var(--radius-lg);
  align-items: stretch;
  box-shadow: var(--shadow-soft);
}

.glass {
  background: linear-gradient(
      135deg,
      rgba(15, 23, 42, 0.84),
      rgba(15, 23, 42, 0.7)
    );
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(18px);
}

/* Inner glass */
.glass-inner {
  background: radial-gradient(circle at top left, rgba(255, 255, 255, 0.06), transparent),
    rgba(15, 23, 42, 0.84);
  border-radius: var(--radius-md);
  border: 1px solid rgba(148, 163, 184, 0.45);
  backdrop-filter: blur(22px);
}

/* Form */
.qr-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.qr-form label {
  font-size: 0.85rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.qr-form input[type="text"] {
  width: 100%;
  padding: 12px 13px;
  border-radius: var(--radius-md);
  border: 1px solid rgba(156, 163, 175, 0.4);
  background: rgba(15, 23, 42, 0.78);
  color: var(--text-main);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-fast),
    transform var(--transition-fast);
}

.qr-form input[type="text"]::placeholder {
  color: rgba(148, 163, 184, 0.7);
}

.qr-form input[type="text"]:focus {
  border-color: rgba(129, 140, 248, 0.85);
  box-shadow: 0 0 0 1px rgba(129, 140, 248, 0.5),
    0 18px 45px rgba(15, 23, 42, 0.9);
  background: rgba(15, 23, 42, 0.92);
  transform: translateY(-1px);
}

.options-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.option {
  flex: 1 1 120px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

select,
input[type="color"] {
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(156, 163, 175, 0.4);
  background: rgba(15, 23, 42, 0.9);
  color: var(--text-main);
  padding: 0 10px;
  font-size: 0.9rem;
  outline: none;
  cursor: pointer;
  transition: border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-fast),
    transform var(--transition-fast);
}

select:focus,
input[type="color"]:focus {
  border-color: rgba(129, 140, 248, 0.9);
  box-shadow: 0 0 0 1px rgba(129, 140, 248, 0.55);
  transform: translateY(-1px);
}

/* Buttons */
.primary-btn,
.secondary-btn {
  border: none;
  outline: none;
  cursor: pointer;
  border-radius: 999px;
  padding: 11px 18px;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: transform var(--transition-fast),
    box-shadow var(--transition-fast),
    background var(--transition-fast),
    color var(--transition-fast),
    opacity var(--transition-fast);
}

.primary-btn {
  margin-top: 4px;
  background: radial-gradient(circle at top left, #a855f7, #6366f1);
  color: #f9fafb;
  box-shadow: 0 14px 30px rgba(79, 70, 229, 0.75);
}

.primary-btn:hover {
  transform: translateY(-1px) scale(1.01);
  box-shadow: 0 18px 40px rgba(79, 70, 229, 0.9);
}

.primary-btn:active {
  transform: translateY(1px) scale(0.99);
  box-shadow: 0 10px 25px rgba(79, 70, 229, 0.6);
}

.secondary-btn {
  margin-top: 14px;
  background: rgba(15, 23, 42, 0.95);
  color: var(--text-main);
  border-radius: 999px;
  padding-inline: 16px;
  border: 1px solid rgba(148, 163, 184, 0.5);
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.95);
}

.secondary-btn:hover:not(:disabled) {
  transform: translateY(-1px);
  background: rgba(15, 23, 42, 1);
}

.secondary-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* QR preview */
.qr-preview {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.qr-wrapper {
  padding: 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.9);
}

#qr-canvas {
  display: block;
}

/* Responsive */
@media (max-width: 720px) {
  .app {
    padding-inline: 18px;
  }

  .card {
    grid-template-columns: 1fr;
    padding: 22px;
  }

  .qr-preview {
    margin-top: 6px;
  }
}

@media (max-width: 480px) {
  .app {
    padding-inline: 14px;
  }

  .card {
    padding: 18px;
    gap: 22px;
  }

  .app-header h1 {
    font-size: 1.7rem;
  }
}