:root {
  --bg: #121212;
  --card-bg: rgba(30, 30, 30, 0.85);
  --surface: #1e1e1e;
  --accent: #3b82f6;
  --text-primary: #e5e7eb;
  --text-secondary: #9ca3af;
  --border: #2e2e2e;
  --focus: #2563eb;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  height: 100%;
}

body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: 'Segoe UI', sans-serif;
  display: flex;
  flex-direction: column;
}

header {
  background: var(--surface);
  padding: 1rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-actions {
  display: flex;
  gap: 1rem;
  -webkit-tap-highlight-color: transparent;
}

.nav-actions a:focus,
.nav-actions a:active,
.nav-actions a.focus-visible:focus-visible {
  outline: none;
  color: var(--text-secondary);
  background: transparent;
  border-color: transparent;
  box-shadow: none;
}

.nav-logo img {
  width: 45px;
  height: 40px;
  cursor: pointer;
}

.page-container {
  flex: 1;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 2rem;
  padding-top: 10vh;
}

.form-card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border-radius: 1rem;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.8);
  padding: 2.5rem;
  width: 100%;
  max-width: 700px;
  transition: transform .3s;
}

.form-card:hover {
  transform: translateY(-5px);
}

.chat-container {
  display: flex;
  flex-direction: column;
}

.chat-logo-wrapper {
  text-align: center;
  margin-bottom: 1.5rem;
}

.chat-logo {
  max-width: 120px;
  height: auto;
  display: inline-block;
}

.chat-input {
  width: 100%;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: .5rem;
  background: var(--surface);
  color: var(--text-primary);
  resize: none;
  margin-bottom: 1rem;
  min-height: 150px;
}

.control-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.btn-icon img {
  display: block;
}

.model-name {
  color: var(--text-secondary);
}

.btn {
  font-weight: 600;
  padding: .75rem 1.25rem;
  border: none;
  border-radius: .5rem;
  cursor: pointer;
  transition: background .3s, transform .3s;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: #2563eb;
  transform: translateY(-2px);
}

.btn-signin {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid transparent;
}

.btn-signin:hover {
  background: var(--surface);
  border-color: var(--border);
}

.btn-signup {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid transparent;
}

.btn-signup:hover {
  background: var(--surface);
  border-color: var(--border);
}

.auth .form-card {
  max-width: 550px;
  padding: 2rem;
}

.auth h1 {
  font-size: 2rem;
  margin-bottom: 1.5rem;
  text-align: center;
  letter-spacing: .05em;
}

.auth .input-group,
.auth .checkbox-group {
  margin-top: 0.8rem;
  margin-bottom: 1.25rem;
}

.auth label {
  color: var(--text-secondary);
  font-size: .95rem;
  margin-bottom: .5rem;
}

.auth input[type="text"] {
  width: 100%;
  padding: .85rem 1rem;
  border: 1px solid var(--border);
  border-radius: .5rem;
  background: var(--surface);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color .3s;
}

.auth input[type="text"]:focus {
  border-color: var(--accent);
  outline: none;
}

.auth input[type="checkbox"] {
  margin-right: .5rem;
  transform: scale(1.1);
}

.auth .btn-primary {
  width: 100%;
  padding: .85rem;
  font-size: 1.05rem;
  border-radius: .5rem;
}

.auth .info {
  text-align: center;
  margin-bottom: 1rem;
  font-size: .95rem;
}

.auth .code {
  font-family: monospace;
  font-size: 1.25rem;
  background: var(--border);
  padding: .75rem;
  border-radius: .5rem;
  text-align: center;
  margin-bottom: 1.25rem;
}

.auth .payment-detail summary {
  background: var(--surface);
  padding: .75rem 1rem;
  border-radius: .5rem;
  cursor: pointer;
  font-weight: 600;
  margin-bottom: .5rem;
}

.auth .payment-detail .details-content {
  background: var(--border);
  padding: 1rem;
  border-radius: .5rem;
  margin-bottom: 1rem;
  text-align: center;
}

.auth .address {
  word-break: break-all;
  font-family: monospace;
  margin-bottom: .75rem;
}

.auth .qr img {
  display: block;
  margin: .5rem auto;
  width: 140px;
  height: 140px;
}

.secure-payment {
  margin: 2rem 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.5rem;
}

.secure-payment img {
  width: 5%;
  height: auto;
}

.secure-payment small {
  font-size: 0.875rem;
  color: #555;
}

@media (max-width: 480px) {
  .auth .form-card {
    padding: 1.5rem;
    width: 90%;
  }

  .auth h1 {
    font-size: 1.75rem;
  }
}