/* =====================================================
   Login Screen v4.0 - 现代登录界面
   ===================================================== */

.login-screen {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
  position: relative;
  overflow: hidden;
  background: var(--bg);
}

/* ===== 背景装饰 ===== */
.login-bg-deco {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 0;
}

.deco-circle {
  position: absolute;
  border-radius: 50%;
  opacity: 0.07;
}

.deco-c1 {
  width: 300px;
  height: 300px;
  background: var(--primary);
  top: -80px;
  right: -60px;
  animation: float 8s ease-in-out infinite;
}

.deco-c2 {
  width: 200px;
  height: 200px;
  background: var(--accent);
  bottom: 10%;
  left: -50px;
  animation: float 10s ease-in-out infinite reverse;
}

.deco-c3 {
  width: 150px;
  height: 150px;
  background: var(--primary);
  bottom: -30px;
  right: 20%;
  animation: float 12s ease-in-out infinite 2s;
}

@keyframes float {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-20px) rotate(5deg); }
}

/* ===== 品牌区域 ===== */
.login-brand {
  text-align: center;
  margin-bottom: var(--space-8);
  position: relative;
  z-index: 1;
  animation: fadeInUp 0.5s ease;
}

.login-logo {
  margin-bottom: var(--space-4);
  display: inline-flex;
  filter: drop-shadow(0 4px 12px rgba(24, 24, 27, 0.15));
}

.login-title {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--text);
  letter-spacing: -0.02em;
  line-height: 1.3;
  margin-bottom: var(--space-2);
}

.login-subtitle {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
  font-weight: var(--font-medium);
}

/* ===== 登录/注册卡片 ===== */
.login-card {
  width: 100%;
  max-width: 380px;
  background: var(--card);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
  position: relative;
  z-index: 1;
  animation: fadeInUp 0.5s ease 0.1s both;
}

.login-card .card-header {
  margin-bottom: var(--space-5);
}

.login-card .card-title {
  font-size: var(--text-xl);
  letter-spacing: -0.01em;
}

.login-card .card-subtitle {
  font-size: var(--text-sm);
}

/* ===== 表单 ===== */
.login-card .form-group {
  margin-bottom: var(--space-4);
}

.login-card .btn-lg {
  margin-top: var(--space-2);
  height: 48px;
}

.btn-arrow {
  font-size: var(--text-lg);
  line-height: 1;
  transition: transform 0.2s ease;
}

.btn-primary:hover .btn-arrow {
  transform: translateX(3px);
}

/* ===== 切换链接 ===== */
.login-switch {
  text-align: center;
  margin-top: var(--space-4);
  font-size: var(--text-sm);
  color: var(--text-tertiary);
}

.login-switch a {
  color: var(--primary);
  font-weight: var(--font-medium);
  margin-left: 2px;
}

.login-switch a:hover {
  text-decoration: underline;
}

/* ===== 底部信息 ===== */
.login-footer {
  margin-top: var(--space-8);
  font-size: var(--text-xs);
  color: var(--text-tertiary);
  position: relative;
  z-index: 1;
  animation: fadeIn 0.5s ease 0.3s both;
}

/* ===== 响应式 ===== */
@media (min-width: 640px) {
  .login-screen {
    padding: var(--space-8);
  }

  .login-title {
    font-size: var(--text-3xl);
  }

  .login-card {
    padding: var(--space-8);
  }
}

@media (min-width: 768px) {
  .deco-c1 { width: 400px; height: 400px; }
  .deco-c2 { width: 300px; height: 300px; }
  .deco-c3 { width: 200px; height: 200px; }
}

/* ===== 暗色模式微调 ===== */
[data-theme="dark"] .login-screen {
  background: var(--bg);
}

[data-theme="dark"] .deco-circle {
  opacity: 0.12;
}

[data-theme="dark"] .login-logo {
  filter: drop-shadow(0 4px 16px rgba(245, 158, 11, 0.2));
}