/* ===== Reset ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #0a0a1a;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ===== 背景装饰光晕 ===== */
.bg-decoration {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.4;
}

.orb-1 {
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, #ff416c, #ff4b2b);
  top: -200px;
  right: -150px;
}

.orb-2 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, #667eea, #764ba2);
  bottom: -180px;
  left: -120px;
}

.orb-3 {
  width: 350px;
  height: 350px;
  background: radial-gradient(circle, #f093fb, #f5576c);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

/* ===== 主容器 ===== */
.container {
  position: relative;
  z-index: 1;
  width: 880px;
  max-width: 94vw;
  height: 560px;
  max-height: 90vh;
  border-radius: 28px;
  box-shadow:
    0 30px 80px rgba(0, 0, 0, 0.6),
    0 0 0 1px rgba(255, 255, 255, 0.06);
  overflow: hidden;
  background: rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(4px);
}

/* ===== Wrapper — 三段式横向布局 ===== */
.wrapper {
  display: flex;
  width: 150%;
  height: 100%;
  will-change: transform;
  transition: transform 0.7s cubic-bezier(0.68, -0.05, 0.265, 1.35);
}

.container.active .wrapper {
  transform: translateX(calc(-100% / 3));
}

/* ===== 每个面板 ===== */
.panel {
  flex: 0 0 calc(100% / 3);
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  padding: 0 44px;
  position: relative;
  transition: background 0.6s ease;
}

.panel form {
  width: 100%;
  max-width: 320px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.panel h1 {
  font-size: 2rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.5px;
  margin-bottom: 4px;
}

.panel .subtitle {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.45);
  margin-bottom: 28px;
}

/* ===== 返回按钮 ===== */
.exit-link {
  position: absolute;
  top: 16px;
  left: 16px;
  z-index: 5;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.08);
  transition: background 0.25s, transform 0.25s;
}

.exit-link:hover {
  background: rgba(255, 255, 255, 0.14);
  transform: scale(1.08);
}

.exit-link:active {
  transform: scale(0.95);
}

.exit-link-right {
  left: auto;
  right: 16px;
}

/* ===== 切换链接 ===== */
.switch-link {
  display: none;
  margin-top: 20px;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.45);
}

.switch-link .link-btn {
  background: none;
  border: none;
  color: #ff416c;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  padding: 0;
}

.switch-link .link-btn:hover {
  color: #ff4b2b;
}

/* ===== 叠加层绿色状态（注册成功转场） ===== */
.container.overlay-green .overlay-bg {
  background: linear-gradient(135deg, #11998e, #38ef7d);
}

/* ===== 注册成功覆盖文字 ===== */
.overlay-success {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #fff;
  padding: 20px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.6s ease, visibility 0.6s ease;
}

.container.overlay-green .overlay-success {
  opacity: 1;
  visibility: visible;
}

.overlay-success svg {
  margin-bottom: 12px;
  filter: drop-shadow(0 4px 12px rgba(255,255,255,0.3));
}

.overlay-success h2 {
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.3px;
}

.container.overlay-green .overlay-side {
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s ease;
}

.overlay-side {
  transition: opacity 0.35s ease;
}

/* 移动端：全宽横幅显示在 Welcome Back 上方 */
@media (max-width: 600px) {
  .container.overlay-green .login-panel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 20;
    padding: 14px 16px;
    background: linear-gradient(135deg, #11998e, #38ef7d);
    color: #fff;
    font-size: 0.92rem;
    font-weight: 600;
    text-align: center;
    animation: mobileBarIn 0.4s ease;
    pointer-events: none;
  }

  .container.overlay-green .login-panel::before {
    content: '✓  Registration Successful!';
  }

  @keyframes mobileBarIn {
    0% { transform: translateY(-100%); opacity: 0; }
    100% { transform: translateY(0); opacity: 1; }
  }
}

/* ===== 错误提示 ===== */
.form-error {
  width: 100%;
  min-height: 0;
  font-size: 0.82rem;
  color: #ff4b2b;
  text-align: center;
  margin-bottom: 0;
  transition: min-height 0.3s, margin 0.3s;
  opacity: 0;
}

.form-error.show {
  min-height: 24px;
  margin-bottom: 8px;
  opacity: 1;
}

/* ===== 输入框 ===== */
.input-group {
  position: relative;
  width: 100%;
  margin-bottom: 14px;
}

.input-group input {
  width: 100%;
  padding: 14px 18px;
  border: 1px solid rgba(255, 255, 255, 0.10);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(12px);
  color: #fff;
  font-size: 0.95rem;
  outline: none;
  transition: border-color 0.3s, box-shadow 0.3s, background 0.3s;
}

.input-group input::placeholder {
  color: rgba(255, 255, 255, 0.30);
}

.input-group input:focus {
  border-color: rgba(255, 65, 108, 0.5);
  box-shadow: 0 0 0 3px rgba(255, 65, 108, 0.12);
  background: rgba(255, 255, 255, 0.10);
}

/* ===== 提交按钮 ===== */
.btn-primary {
  width: 100%;
  padding: 14px;
  margin-top: 6px;
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, #ff416c, #ff4b2b);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 2px;
  transition: transform 0.25s, box-shadow 0.25s;
  box-shadow: 0 8px 28px rgba(255, 65, 108, 0.30);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 36px rgba(255, 65, 108, 0.45);
}

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

/* ===== 遮罩面板 ===== */
.overlay-panel {
  overflow: hidden;
  padding: 0;
  position: relative;
}

.overlay-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #ff416c, #ff4b2b);
  z-index: 0;
  transition: background 1s ease-in-out;
}

.overlay-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 30%, rgba(255,255,255,0.12) 0%, transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(255,255,255,0.08) 0%, transparent 50%);
  pointer-events: none;
}

.overlay-content {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 1;
  width: 200%;
  height: 100%;
  display: flex;
  transform: translateX(-50%);
  transition: transform 0.7s cubic-bezier(0.68, -0.05, 0.265, 1.35);
}

.container.active .overlay-content {
  transform: translateX(0);
}

/* ===== 遮罩两侧文字 ===== */
.overlay-side {
  width: 50%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 0 48px;
  text-align: center;
  color: #fff;
}

.overlay-side h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 8px;
  color: #fff;
}

.overlay-side p {
  font-size: 0.95rem;
  opacity: 0.80;
  margin-bottom: 28px;
  line-height: 1.5;
}

/* ===== 透明边框按钮 ===== */
.btn-ghost {
  padding: 12px 48px;
  border: 1.5px solid rgba(255, 255, 255, 0.70);
  border-radius: 50px;
  background: transparent;
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 1px;
  transition: all 0.3s;
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.20);
}

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

/* ================================================================
   平板 ≤820px
   ================================================================ */
@media (max-width: 820px) {
  .container {
    width: 96vw;
    height: 92vh;
    max-height: 600px;
    border-radius: 24px;
  }

  .panel {
    padding: 0 32px;
  }

  .panel h1,
  .overlay-side h1 {
    font-size: 1.6rem;
  }

  .overlay-side {
    padding: 0 32px;
  }

  .overlay-side p {
    margin-bottom: 20px;
    font-size: 0.88rem;
  }

  .btn-ghost {
    padding: 10px 36px;
    font-size: 0.85rem;
  }
}

/* ================================================================
   手机 ≤600px — 全屏表单，隐藏遮罩
   ================================================================ */
@media (max-width: 600px) {
  body {
    align-items: flex-start;
    padding: 10px;
    overflow: hidden;
  }

  .container {
    width: 100%;
    max-width: 100%;
    height: 100vh;
    max-height: 100vh;
    border-radius: 20px;
    box-shadow:
      0 20px 60px rgba(0, 0, 0, 0.5),
      0 0 0 1px rgba(255, 255, 255, 0.05);
    background: rgba(255, 255, 255, 0.04);
    backdrop-filter: blur(4px);
  }

  .wrapper {
    width: 200%;
  }

  .panel {
    flex: 0 0 50%;
    padding: 0 28px;
  }

  .panel form {
    max-width: 360px;
  }

  .panel h1 {
    font-size: 1.7rem;
  }

  .panel .subtitle {
    margin-bottom: 24px;
    font-size: 0.85rem;
  }

  .input-group input {
    padding: 15px 16px;
    font-size: 0.95rem;
    border-radius: 14px;
  }

  .btn-primary {
    padding: 15px;
    font-size: 1rem;
    border-radius: 14px;
  }

  .container.active .wrapper {
    transform: translateX(-50%);
  }

  .overlay-panel {
    display: none;
  }

  .switch-link {
    display: block;
  }

  .bg-decoration .orb {
    opacity: 0.25;
  }
}

/* ================================================================
   小屏手机 ≤400px
   ================================================================ */
@media (max-width: 400px) {
  body {
    padding: 6px;
  }

  .container {
    border-radius: 16px;
  }

  .panel {
    padding: 0 20px;
  }

  .panel h1 {
    font-size: 1.4rem;
  }

  .input-group input {
    padding: 13px 14px;
    font-size: 0.88rem;
    border-radius: 12px;
  }

  .btn-primary {
    padding: 13px;
    font-size: 0.92rem;
  }

  .switch-link {
    margin-top: 16px;
    font-size: 0.8rem;
  }

  .bg-decoration .orb {
    opacity: 0.18;
  }
}

/* ================================================================
   横屏
   ================================================================ */
@media (max-height: 500px) and (orientation: landscape) {
  body {
    padding: 6px;
  }

  .container {
    height: 88vh;
    border-radius: 16px;
  }

  .panel {
    padding: 0 24px;
  }

  .panel h1 {
    font-size: 1.3rem;
  }

  .panel .subtitle {
    margin-bottom: 12px;
    font-size: 0.78rem;
  }

  .input-group {
    margin-bottom: 8px;
  }

  .input-group input {
    padding: 10px 14px;
    font-size: 0.82rem;
  }

  .btn-primary {
    padding: 10px;
    font-size: 0.85rem;
    margin-top: 2px;
  }

  .switch-link {
    margin-top: 10px;
    font-size: 0.75rem;
  }

  .overlay-side {
    padding: 0 16px;
  }

  .overlay-side h1 {
    font-size: 1.1rem;
    margin-bottom: 4px;
  }

  .overlay-side p {
    margin-bottom: 10px;
    font-size: 0.75rem;
  }

  .btn-ghost {
    padding: 7px 20px;
    font-size: 0.75rem;
  }
}