:root {
  --bg: #07090e;
  --surface: #0f141f;
  --surface-elevated: #161e2e;
  --border: #1f293d;
  --border-focus: #8b5cf6;
  --text: #f3f4f6;
  --text-muted: #9ca3af;
  --accent: #8b5cf6;
  --accent-hover: #7c3aed;
  --cyan: #06b6d4;
  --emerald: #10b981;
  --rose: #f43f5e;
  --amber: #f59e0b;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 1rem;
  width: 100%;
}

/* Header */
.app-header {
  background: rgba(15, 20, 31, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.logo-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.logo-icon {
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--accent) 0%, var(--cyan) 100%);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}
.logo-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.01em;
}
.logo-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
}
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* Buttons */
.btn-primary {
  background: linear-gradient(135deg, var(--accent) 0%, #6d28d9 100%);
  color: #fff;
  border: none;
  padding: 0.7rem 1.25rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s ease, transform 0.05s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
}
.btn-primary:hover { opacity: 0.92; }
.btn-primary:active { transform: translateY(1px); }

.btn-secondary {
  background: var(--surface-elevated);
  color: var(--text-muted);
  border: 1px solid var(--border);
  padding: 0.4rem 0.85rem;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}
.btn-secondary:hover {
  background: var(--border);
  color: #fff;
}

/* Login Screen */
.screen-login {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
}
.login-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2rem;
  max-width: 420px;
  width: 100%;
  box-shadow: 0 20px 40px -15px rgba(0,0,0,0.7);
}
.login-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  text-align: center;
}
.login-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  text-align: center;
}
.form-group {
  margin-bottom: 1.1rem;
}
.form-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  color: var(--text);
}
.form-input {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  color: #fff;
  padding: 0.7rem 0.85rem;
  border-radius: 8px;
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.15s ease;
}
.form-input:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 2px rgba(139, 92, 246, 0.2);
}
.alert-box {
  background: rgba(244, 63, 94, 0.15);
  border: 1px solid rgba(244, 63, 94, 0.3);
  color: #fca5a5;
  padding: 0.6rem 0.85rem;
  border-radius: 6px;
  font-size: 0.85rem;
  margin-bottom: 1rem;
  display: none;
}

/* Dashboard */
.screen-dashboard {
  flex: 1;
  padding: 2rem 0;
}
.input-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}
.input-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.3rem;
}
.input-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}
.url-bar {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}
.url-input {
  flex: 1;
  min-width: 260px;
  background: var(--bg);
  border: 1px solid var(--border);
  color: #fff;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  font-size: 0.9rem;
  outline: none;
}
.url-input:focus {
  border-color: var(--border-focus);
}
.quick-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
  align-items: center;
}
.quick-label {
  font-size: 0.75rem;
  color: var(--text-muted);
}
.quick-chip {
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.3rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.15s ease;
}
.quick-chip:hover {
  background: rgba(139, 92, 246, 0.15);
  color: #c4b5fd;
  border-color: rgba(139, 92, 246, 0.4);
}

/* Results Grid */
.result-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}
@media (min-width: 860px) {
  .result-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.5rem;
}
.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  padding-bottom: 0.75rem;
}
.card-title {
  font-size: 1rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* Badges */
.badge-instrumental {
  background: rgba(6, 182, 212, 0.15);
  color: #67e8f9;
  border: 1px solid rgba(6, 182, 212, 0.3);
  padding: 0.25rem 0.6rem;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}
.badge-vocal {
  background: rgba(245, 158, 11, 0.15);
  color: #fcd34d;
  border: 1px solid rgba(245, 158, 11, 0.3);
  padding: 0.25rem 0.6rem;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.dna-list {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}
.dna-item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.85rem;
  gap: 0.75rem;
  border-bottom: 1px solid rgba(255,255,255,0.03);
  padding-bottom: 0.4rem;
}
.dna-label {
  color: var(--text-muted);
  font-size: 0.8rem;
}
.dna-value {
  font-weight: 600;
  text-align: right;
}

.secret-box {
  margin-top: 1.25rem;
  background: rgba(139, 92, 246, 0.08);
  border: 1px solid rgba(139, 92, 246, 0.2);
  border-radius: 8px;
  padding: 0.85rem;
  font-size: 0.85rem;
  color: #ddd6fe;
}
.secret-box strong {
  color: #fff;
  display: block;
  margin-bottom: 0.3rem;
}

/* Similar Songs */
.twins-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.twin-item {
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.9rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.twin-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}
.twin-name {
  font-weight: 700;
  font-size: 0.95rem;
}
.twin-match {
  background: rgba(16, 185, 129, 0.15);
  color: #6ee7b7;
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 0.2rem 0.5rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 700;
}
.twin-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
}
.twin-links {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.25rem;
}
.btn-link {
  color: var(--cyan);
  font-size: 0.8rem;
  text-decoration: none;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.2rem;
}
.btn-link:hover { text-decoration: underline; }

/* AI Prompts Section */
.prompts-card {
  grid-column: 1 / -1;
}
.prompt-box {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.85rem;
  margin-bottom: 0.6rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.8rem;
  color: #e5e7eb;
  white-space: pre-wrap;
  word-break: break-word;
}
.prompt-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

/* Spinner */
.spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255,255,255,0.3);
  border-radius: 50%;
  border-top-color: #fff;
  animation: spin 0.8s linear infinite;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--emerald);
  color: #064e3b;
  font-weight: 700;
  padding: 0.75rem 1.4rem;
  border-radius: 8px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.5);
  font-size: 0.85rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  transform: translateY(10px);
  z-index: 999;
}
.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* Footer */
.app-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 0.5rem;
}
.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
}
.footer-links a:hover {
  color: var(--text);
  text-decoration: underline;
}