:root {
  --primary: #00ccff;
  --secondary: #9d4dff;
  --success: #00ffaa;
  --warning: #ffcc00;
  --danger: #ff3b3b;
  --text-main: #ffffff;
  --text-muted: rgba(255, 255, 255, 0.6);
  --glass-bg: rgba(18, 18, 24, 0.7);
  --glass-border: rgba(255, 255, 255, 0.12);
  --font-main: system-ui, -apple-system, sans-serif;
  --ease: cubic-bezier(0.23, 1, 0.32, 1);
  --flip-ease: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-main);
  background: #06070a;
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow-x: hidden;
}

#bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
}

.register-wrapper {
  width: 100%;
  max-width: 480px;
  padding: 20px;
  position: relative;
  z-index: 10;
  display: flex;
  flex-direction: column;
  gap: 25px;
  perspective: 1200px;
}

.register-container {
  background: transparent;
  border: none;
  box-shadow: none;
  padding: 0;
  opacity: 0;
  transform: translateY(30px);
  animation: cardEntry 0.8s var(--ease) forwards;
}

.card-faces {
  width: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.8s var(--flip-ease);
}

.register-container.flipped .card-faces {
  transform: rotateY(180deg);
}

.card-face {
  width: 100%;
  backface-visibility: hidden;
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 40px 36px;
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.6);
}

.face-back {
  position: absolute;
  top: 0;
  left: 0;
  transform: rotateY(180deg);
}

.card-header {
  text-align: center;
  margin-bottom: 30px;
}

.app-title {
  font-size: 28px;
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #fff 0%, #a0c4ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.app-subtitle {
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 2px;
  text-transform: uppercase;
  font-weight: 600;
}

.register-form {
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.input-group {
  position: relative;
  width: 100%;
}

.input-group input {
  width: 100%;
  padding: 10px 0 10px 32px;
  background: transparent;
  border: none;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  color: #fff;
  font-size: 15px;
  border-radius: 0;
  transition: all 0.3s;
}

.input-group input:focus {
  outline: none;
  border-color: transparent;
}

.input-group label {
  position: absolute;
  left: 32px;
  top: 10px;
  color: rgba(255, 255, 255, 0.4);
  font-size: 14px;
  pointer-events: none;
  transition: all 0.3s var(--ease);
}

.input-group input:focus ~ label,
.input-group input:not(:placeholder-shown) ~ label {
  top: -14px;
  left: 0;
  font-size: 11px;
  color: var(--primary);
}

.input-icon {
  position: absolute;
  left: 0;
  top: 12px;
  font-size: 18px;
  color: rgba(255, 255, 255, 0.3);
  transition: color 0.3s;
}

.input-group input:focus ~ .input-icon {
  color: var(--primary);
}

.input-line {
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--secondary), var(--primary));
  transition: all 0.4s var(--ease);
  transform: translateX(-50%);
}

.input-group input:focus ~ .input-line {
  width: 100%;
  box-shadow: 0 0 10px rgba(0, 204, 255, 0.3);
}

.strength-bar {
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background: transparent;
  overflow: hidden;
  opacity: 0;
  transition: opacity 0.3s;
}

.input-group input:focus ~ .strength-bar {
  opacity: 1;
}

.bar-fill {
  height: 100%;
  width: 0;
  transition: width 0.4s var(--ease), background 0.4s;
}

.strength-text {
  position: absolute;
  right: 0;
  top: 10px;
  font-size: 12px;
  font-weight: 700;
  opacity: 0;
  transform: translateX(10px);
  transition: all 0.3s var(--ease);
  pointer-events: none;
}

.input-group.has-strength .strength-text {
  opacity: 1;
  transform: translateX(0);
}

.input-group.strength-weak .input-line { background: var(--danger); width: 100%; box-shadow: 0 0 15px rgba(255, 59, 59, 0.6); }
.input-group.strength-weak .input-icon { color: var(--danger); }
.input-group.strength-weak .strength-text { color: var(--danger); }

.input-group.strength-medium .input-line { background: var(--warning); width: 100%; box-shadow: 0 0 15px rgba(255, 204, 0, 0.6); }
.input-group.strength-medium .input-icon { color: var(--warning); }
.input-group.strength-medium .strength-text { color: var(--warning); }

.input-group.strength-strong .input-line { background: var(--success); width: 100%; box-shadow: 0 0 15px rgba(0, 255, 170, 0.6); }
.input-group.strength-strong .input-icon { color: var(--success); }
.input-group.strength-strong .strength-text { color: var(--success); }

.input-group.error .input-line {
  width: 100%;
  background: var(--danger);
  box-shadow: 0 0 10px var(--danger);
}
.input-group.error .input-icon,
.input-group.error label {
  color: var(--danger);
}

.shake-warning {
  animation: shake 0.4s ease-in-out;
}

.captcha-row {
  display: flex;
  align-items: flex-end;
  gap: 16px;
}

.captcha-input {
  flex: 1;
}

.captcha-img-wrap {
  width: 100px;
  height: 40px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.15);
  cursor: pointer;
  transition: border-color 0.3s;
}

.captcha-img-wrap:hover {
  border-color: var(--primary);
}

.captcha-img-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.error-msg {
  font-size: 13px;
  color: var(--danger);
  text-align: center;
  min-height: 20px;
  display: none;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.error-msg.show {
  display: flex;
  animation: shake 0.4s ease-in-out;
}

.submit-btn {
  position: relative;
  width: 100%;
  padding: 14px;
  background: #ffffff;
  color: #000000;
  border: none;
  border-radius: 12px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  overflow: hidden;
  transition: transform 0.2s, background 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.submit-btn:hover {
  transform: scale(1.02);
}

.submit-btn:active {
  transform: scale(0.98);
}

.btn-glow {
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255,255,255,0.8) 0%, transparent 60%);
  transform: scale(0);
  transition: transform 0.5s;
  pointer-events: none;
}

.submit-btn:hover .btn-glow {
  transform: scale(1);
}

.loading-spinner {
  display: none;
  width: 20px;
  height: 20px;
  border: 2px solid rgba(0,0,0,0.2);
  border-left-color: #000;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

.submit-btn.loading .btn-text { display: none; }
.submit-btn.loading .btn-glow { display: none; }
.submit-btn.loading .loading-spinner { display: block; }

/* 倒计时 SVG 圆环 */
.countdown-wrap {
  position: relative;
  width: 96px;
  height: 96px;
  margin: 0 auto 20px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.countdown-svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.countdown-bg {
  fill: none;
  stroke: rgba(255, 255, 255, 0.08);
  stroke-width: 6;
}

.countdown-progress {
  fill: none;
  stroke: var(--primary);
  stroke-width: 6;
  stroke-linecap: round;
  stroke-dasharray: 238.76;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.3s linear, stroke 0.3s ease;
}

.countdown-text {
  position: absolute;
  font-size: 24px;
  font-weight: 800;
  color: var(--primary);
  transition: color 0.3s ease;
  font-family: monospace;
}

.card-footer-links {
  text-align: center;
  font-size: 14px;
  color: var(--text-muted);
  margin-top: 5px;
}

.login-link {
  color: var(--primary);
  font-weight: 600;
  margin-left: 6px;
  text-decoration: none;
  transition: color 0.2s;
}

.login-link:hover {
  color: #fff;
}

.simple-footer {
  text-align: center;
}

.copyright-text {
  font-size: 12px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.4);
}

#toast-overlay {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 9999;
  display: none;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.custom-toast {
  background: rgba(18, 18, 24, 0.9);
  backdrop-filter: blur(16px);
  border: 1px solid var(--glass-border);
  color: #fff;
  padding: 12px 24px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
  transform: scale(0.9);
  transition: transform 0.3s ease;
}

.custom-toast i {
  color: var(--primary);
  font-size: 18px;
}

@keyframes cardEntry {
  to { opacity: 1; transform: translateY(0); }
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}

@media (max-width: 480px) {
  .form-row { grid-template-columns: 1fr; gap: 20px; }
  .card-face { padding: 32px 24px; }
  .app-title { font-size: 24px; }
}