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

:root {
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #a5b4fc;
  --bg-1: #667eea;
  --bg-2: #764ba2;
  --card-bg: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --success: #10b981;
  --error: #ef4444;
  --radius: 16px;
  --shadow: 0 20px 60px rgba(76, 60, 160, 0.35);
}

html,
body {
  min-height: 100%;
}

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB",
    -apple-system, BlinkMacSystemFont, sans-serif;
  background: linear-gradient(135deg, var(--bg-1) 0%, var(--bg-2) 100%);
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: 100%;
  max-width: 520px;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  animation: cardIn 0.5s ease both;
}

@keyframes cardIn {
  from {
    opacity: 0;
    transform: translateY(24px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.card-header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  padding: 28px 32px;
}

.card-header h1 {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 1px;
}

.card-header p {
  margin-top: 6px;
  font-size: 13px;
  opacity: 0.85;
}

.card-body {
  padding: 32px;
}

.field {
  margin-bottom: 24px;
}

.field label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.field label .required {
  color: var(--error);
  margin-left: 2px;
}

.field input {
  width: 100%;
  padding: 12px 14px;
  font-size: 15px;
  color: var(--text);
  background: #f8fafc;
  border: 2px solid var(--border);
  border-radius: 10px;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s, background 0.2s;
}

.field input:focus {
  border-color: var(--primary);
  background: #fff;
  box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.15);
}

.field input.invalid {
  border-color: var(--error);
}

.field .hint {
  display: none;
  margin-top: 6px;
  font-size: 12px;
  color: var(--error);
}

.field .hint.show {
  display: block;
  animation: shake 0.3s ease;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  padding: 14px 20px;
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s, opacity 0.15s;
  box-shadow: 0 6px 20px rgba(79, 70, 229, 0.35);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 26px rgba(79, 70, 229, 0.45);
}

.btn:active {
  transform: translateY(0);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-secondary {
  background: #f1f5f9;
  color: var(--text);
  box-shadow: none;
  border: 2px solid var(--border);
}

.btn-secondary:hover {
  background: #e2e8f0;
  box-shadow: none;
}

/* ---------- result panel ---------- */
.result {
  margin-top: 24px;
  border: 2px dashed var(--primary-light);
  border-radius: 12px;
  background: #f5f7ff;
  padding: 20px;
  display: none;
}

.result.show {
  display: block;
  animation: resultIn 0.4s ease both;
}

@keyframes resultIn {
  from {
    opacity: 0;
    transform: scale(0.96);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.result .result-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--primary-dark);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.result textarea {
  width: 100%;
  height: 110px;
  resize: vertical;
  padding: 10px 12px;
  font-size: 12px;
  line-height: 1.5;
  font-family: "Consolas", "Courier New", monospace;
  word-break: break-all;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  outline: none;
}

.result-actions {
  display: flex;
  gap: 10px;
  margin-top: 12px;
}

.result-actions .btn {
  padding: 10px 14px;
  font-size: 13px;
  flex: 1;
}

.tip {
  margin-top: 14px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--text-muted);
}

.tip a {
  color: var(--primary);
  font-weight: 600;
  text-decoration: none;
}

.tip a:hover {
  text-decoration: underline;
}

/* ---------- toast ---------- */
.toast {
  position: fixed;
  left: 50%;
  bottom: 36px;
  transform: translateX(-50%) translateY(20px);
  background: rgba(30, 41, 59, 0.92);
  color: #fff;
  padding: 12px 22px;
  border-radius: 999px;
  font-size: 14px;
  opacity: 0;
  pointer-events: none;
  transition: all 0.3s ease;
  z-index: 99;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ---------- footer ---------- */
.footer {
  text-align: center;
  margin-top: 18px;
  font-size: 12px;
  color: rgba(255, 255, 255, 0.7);
}