:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --bg-input: #0d1117;

  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;

  --accent-primary: #58a6ff;
  --accent-primary-hover: #79b8ff;
  --accent-success: #3fb950;
  --accent-success-hover: #56d364;
  --accent-danger: #f85149;
  --accent-warning: #d29922;

  --border-default: #30363d;
  --border-muted: #21262d;

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);

  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  padding: 24px;
  min-height: 100vh;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-family);
  line-height: 1.6;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* Typography */
h1 {
  margin: 0 0 8px 0;
  font-size: 2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-success));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

#pageSubtitle {
  margin: 0 0 32px 0;
  color: var(--text-secondary);
  font-size: 1rem;
}

/* Sections */
#heading {
  text-align: center;
  margin-bottom: 8px;
}

#multisigSection {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 560px;
  padding: 24px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

#xpubRadioContainer {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 560px;
  margin-top: 24px;
  padding: 20px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
}

#elementsBelowXpub {
  display: none;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 560px;
  margin-top: 24px;
  padding: 24px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

/* Form Elements */
textarea,
input[type="text"] {
  width: 100%;
  padding: 12px 14px;
  font-family: var(--font-family);
  font-size: 0.875rem;
  color: var(--text-primary);
  background: var(--bg-input);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  resize: vertical;
}

textarea:focus,
input[type="text"]:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.15);
}

textarea::placeholder,
input::placeholder {
  color: var(--text-muted);
}

#multisigConfigInput {
  min-height: 120px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  line-height: 1.5;
}

label {
  display: block;
  margin-bottom: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

/* Buttons */
button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-family: var(--font-family);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--bg-primary);
  background: var(--accent-success);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

button:hover {
  background: var(--accent-success-hover);
}

button:active {
  transform: scale(0.98);
}

button:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(63, 185, 80, 0.3);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Upload Button */
#uploadContainer {
  width: 100%;
  margin-bottom: 16px;
}

#fileInput {
  display: none;
}

#uploadButton {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 14px 20px;
  font-family: var(--font-family);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-tertiary);
  border: 2px dashed var(--border-default);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

#uploadButton:hover {
  background: var(--bg-input);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

/* Extract Button */
#extractXpubsButton {
  width: 100%;
  margin-top: 16px;
  padding: 12px 20px;
}

/* XPub Radio Buttons */
input[type="radio"] {
  display: none;
}

#xpubRadioContainer label {
  display: block;
  width: 100%;
  padding: 12px 16px;
  margin: 6px 0;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

#xpubRadioContainer label:hover {
  background: var(--bg-input);
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

#xpubRadioContainer input[type="radio"]:checked + label {
  background: rgba(88, 166, 255, 0.1);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  font-weight: 500;
}

#xpubRadioContainer br {
  display: none;
}

/* Derivation Controls */
#derivationControls {
  display: flex;
  gap: 16px;
  width: 100%;
  margin-bottom: 20px;
}

#addressTypeContainer,
#relativePathContainer {
  flex: 1;
}

#addressTypeContainer label,
#relativePathContainer label {
  display: block;
  margin-bottom: 6px;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* Taproot Warning */
#taprootWarning {
  display: none;
  width: 100%;
  padding: 12px 16px;
  margin-bottom: 16px;
  font-size: 0.8125rem;
  color: var(--accent-warning);
  background: rgba(210, 153, 34, 0.1);
  border: 1px solid rgba(210, 153, 34, 0.3);
  border-radius: var(--radius-md);
}

#taprootWarning i {
  margin-right: 8px;
}

#taprootWarning.visible {
  display: block;
}

select,
input[type="number"] {
  width: 100%;
  padding: 10px 12px;
  font-family: var(--font-family);
  font-size: 0.875rem;
  color: var(--text-primary);
  background: var(--bg-input);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  cursor: pointer;
}

select:hover,
input[type="number"]:hover {
  border-color: var(--text-muted);
}

select:focus,
input[type="number"]:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.15);
}

select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

input[type="number"] {
  -moz-appearance: textfield;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Derivation Path Result */
#derivationPathResult {
  width: 100%;
  padding: 16px;
  margin-bottom: 20px;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--accent-primary);
}

#derivationPathResult.error {
  border-left-color: var(--accent-danger);
}

#derivationPathResult .path-info {
  display: flex;
  flex-direction: column;
  margin-bottom: 12px;
}

#derivationPathResult .path-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 4px;
}

#derivationPathResult strong {
  display: block;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--accent-warning);
  background: var(--bg-input);
  border-radius: var(--radius-sm);
  word-break: break-all;
}

#derivationPathResult strong.address {
  color: var(--accent-success);
}

#derivationPathResult .instructions {
  margin: 12px 0 0 0;
  padding-top: 12px;
  border-top: 1px solid var(--border-muted);
  font-size: 0.8125rem;
  color: var(--text-muted);
}

#derivationPathResult .error-message {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--accent-danger);
}

#derivationPathResult .error-message i {
  font-size: 1rem;
}

/* Message & Signature Inputs */
#messageInputContainer,
#signatureInputContainer {
  width: 100%;
  margin-bottom: 16px;
}

#signatureFormatContainer {
  margin-bottom: 12px;
}

#signatureFormatContainer label {
  font-size: 0.75rem;
  color: var(--text-muted);
}

#signatureFormatSelect {
  margin-top: 6px;
}

#buttonHolder {
  display: flex;
  align-items: center;
  gap: 8px;
}

#messageInput,
#signatureInput {
  flex: 1;
}

#copyButton,
#exportButton {
  flex-shrink: 0;
  padding: 10px 12px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-default);
}

#copyButton:hover,
#exportButton:hover {
  background: var(--bg-input);
  color: var(--accent-primary);
  border-color: var(--accent-primary);
}

#copyNotification {
  display: none;
  padding: 6px 12px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent-success);
  background: rgba(63, 185, 80, 0.1);
  border-radius: var(--radius-sm);
  animation: fadeIn var(--transition-fast);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

#evaluateSignatureButton {
  width: 100%;
  margin-top: 8px;
  padding: 12px 20px;
  background: var(--accent-primary);
}

#evaluateSignatureButton:hover {
  background: var(--accent-primary-hover);
}

#evaluateSignatureButton:focus {
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.3);
}

/* Validation Result */
#validationResult {
  margin-top: 16px;
  padding: 12px 16px;
  font-size: 0.9375rem;
  font-weight: 600;
  text-align: center;
  border-radius: var(--radius-md);
}

#validationResult:not(:empty) {
  background: rgba(248, 81, 73, 0.1);
  color: var(--accent-danger);
  border: 1px solid rgba(248, 81, 73, 0.3);
}

#validationResult.success {
  background: rgba(63, 185, 80, 0.1);
  color: var(--accent-success);
  border: 1px solid rgba(63, 185, 80, 0.3);
}

/* Import Descriptor Button */
#importDescriptorContainer {
  margin-top: 24px;
}

#importDescriptorButton {
  display: none;
  padding: 10px 20px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-default);
}

#importDescriptorButton:hover {
  background: var(--bg-input);
  color: var(--text-primary);
  border-color: var(--text-muted);
}

/* Footer */
footer {
  margin-top: 48px;
  padding: 24px;
  text-align: center;
  border-top: 1px solid var(--border-muted);
  max-width: 560px;
  width: 100%;
}

footer p {
  margin: 8px 0;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

footer a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

footer a:hover {
  color: var(--accent-primary-hover);
  text-decoration: underline;
}

/* QR Code */
#qr-code-img {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  max-width: 280px;
  max-height: 280px;
  padding: 16px;
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
  z-index: 1000;
}

#donationLink:hover ~ #qr-code-img {
  opacity: 1;
  visibility: visible;
}

/* Responsive */
@media (max-width: 640px) {
  body {
    padding: 16px;
  }

  h1 {
    font-size: 1.5rem;
  }

  #multisigSection,
  #xpubRadioContainer,
  #elementsBelowXpub {
    padding: 16px;
  }

  #derivationControls {
    flex-direction: column;
    gap: 12px;
  }

  #buttonHolder {
    flex-wrap: wrap;
  }

  #messageInput,
  #signatureInput {
    width: 100%;
    margin-bottom: 8px;
  }
}