add PasswordInput component

packages/vant-css/src/index.css

@@ -34,6 +34,7 @@
 @import './radio.css';
 @import './switch.css';
 @import './uploader.css';
+@import './password-input.css';
 @import './number-keyboard.css';
 
 /* action components */

packages/vant-css/src/password-input.css

@@ -0,0 +1,59 @@
+@import "./common/var.css";
+
+.van-password-input {
+  margin: 0 15px;
+  user-select: none;
+  position: relative;
+
+  &:focus {
+    outline: none;
+  }
+
+  &__info,
+  &__error-info {
+    font-size: 14px;
+    margin-top: 15px;
+    text-align: center;
+  }
+
+  &__info {
+    color: $gray-dark;
+  }
+
+  &__error-info {
+    color: $red;
+  }
+
+  &__security {
+    width: 100%;
+    height: 50px;
+    display: flex;
+    background-color: $white;
+
+    &::after {
+      border-radius: 6px;
+    }
+
+    li {
+      flex: 1;
+      height: 100%;
+      position: relative;
+
+      &:not(:first-of-type)::after {
+        border-left-width: 1px;
+      }
+    }
+
+    i {
+      position: absolute;
+      left: 50%;
+      top: 50%;
+      width: 10px;
+      height: 10px;
+      margin: -5px 0 0 -5px;
+      visibility: hidden;
+      border-radius: 100%;
+      background-color: $black;
+    }
+  }
+}