feat(back-button): enhance button styles and add variant support; refactor back navigation in sidebar and coins rules screen

src/app/_components/back-button.module.css

@@ -1,29 +1,74 @@
 .backButton {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0;
+  color: var(--color-auth-text-primary);
+  cursor: pointer;
+  border: 0;
+  border-radius: 999px;
+  text-decoration: none;
+  transition:
+    background 0.15s ease,
+    box-shadow 0.18s ease,
+    transform 0.05s ease;
+}
+
+.floating {
   position: absolute;
   top: var(--spacing-xl);
   left: var(--spacing-xl);
   z-index: 2;
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
   width: var(--back-button-size);
   height: var(--back-button-size);
   padding: 0 2px 0 0;
-  color: var(--color-auth-text-primary);
-  cursor: pointer;
   background: var(--color-auth-surface);
-  border: none;
-  border-radius: 50%;
   box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
-  transition:
-    background 0.15s ease,
-    transform 0.05s ease;
 }
 
-.backButton:hover {
+.soft {
+  width: 42px;
+  height: 42px;
+  color: #21191d;
+  border: 1px solid rgba(25, 19, 22, 0.08);
+  background: rgba(255, 255, 255, 0.82);
+  box-shadow: 0 10px 22px rgba(50, 30, 40, 0.08);
+}
+
+.ghost {
+  width: 32px;
+  height: 32px;
+  color: #000000;
+  background: transparent;
+}
+
+.floating:hover {
   background: rgba(0, 0, 0, 0.04);
 }
 
-.backButton:active {
+.soft:hover {
+  background: #ffffff;
+  box-shadow: 0 14px 26px rgba(50, 30, 40, 0.12);
+  transform: translateY(-1px);
+}
+
+.ghost:hover {
+  opacity: 0.7;
+}
+
+.floating:active {
   transform: scale(0.96);
 }
+
+.soft:active {
+  transform: translateY(1px);
+}
+
+.ghost:active {
+  transform: scale(0.96);
+}
+
+.backButton:focus-visible {
+  outline: 2px solid #f657a0;
+  outline-offset: 3px;
+}

src/app/_components/back-button.tsx

@@ -1,28 +1,64 @@
 "use client";
 
 import { ChevronLeft } from "lucide-react";
+import Link, { type LinkProps } from "next/link";
 
 import styles from "./back-button.module.css";
 
-export interface BackButtonProps {
+interface BackButtonBaseProps {
-  onClick: () => void;
   className?: string;
   ariaLabel?: string;
+  iconSize?: number;
+  variant?: "floating" | "soft" | "ghost";
 }
 
+type BackButtonLinkProps = BackButtonBaseProps & {
+  href: LinkProps["href"];
+  onClick?: never;
+};
+
+type BackButtonActionProps = BackButtonBaseProps & {
+  href?: never;
+  onClick: () => void;
+};
+
+export type BackButtonProps = BackButtonLinkProps | BackButtonActionProps;
+
 export function BackButton({
+  href,
   onClick,
   className,
   ariaLabel = "Back",
+  iconSize = 24,
+  variant = "floating",
 }: BackButtonProps) {
+  const buttonClassName = [
+    styles.backButton,
+    styles[variant],
+    className,
+  ]
+    .filter(Boolean)
+    .join(" ");
+  const icon = (
+    <ChevronLeft size={iconSize} strokeWidth={2.5} aria-hidden="true" />
+  );
+
+  if (href) {
+    return (
+      <Link href={href} className={buttonClassName} aria-label={ariaLabel}>
+        {icon}
+      </Link>
+    );
+  }
+
   return (
     <button
       type="button"
-      className={[styles.backButton, className].filter(Boolean).join(" ")}
+      className={buttonClassName}
       onClick={onClick}
       aria-label={ariaLabel}
     >
-      <ChevronLeft size={20} strokeWidth={2.5} aria-hidden="true" />
+      {icon}
     </button>
   );
 }

src/app/coins-rules/coins-rules-screen.module.css

@@ -15,36 +15,6 @@
   gap: 18px;
 }
 
-.backLink {
-  display: inline-flex;
-  width: 42px;
-  height: 42px;
-  align-items: center;
-  justify-content: center;
-  color: #21191d;
-  text-decoration: none;
-  border: 1px solid rgba(25, 19, 22, 0.08);
-  border-radius: 999px;
-  background: rgba(255, 255, 255, 0.82);
-  box-shadow: 0 10px 22px rgba(50, 30, 40, 0.08);
-  transition: background 0.18s ease, box-shadow 0.18s ease, transform 0.16s ease;
-}
-
-.backLink:hover {
-  background: #ffffff;
-  box-shadow: 0 14px 26px rgba(50, 30, 40, 0.12);
-  transform: translateY(-1px);
-}
-
-.backLink:active {
-  transform: translateY(1px);
-}
-
-.backLink:focus-visible {
-  outline: 2px solid #f657a0;
-  outline-offset: 3px;
-}
-
 .hero {
   position: relative;
   overflow: hidden;

src/app/coins-rules/coins-rules-screen.tsx

@@ -1,7 +1,6 @@
 "use client";
 
 import {
-  ArrowLeft,
   Coins,
   Gift,
   ImageIcon,
@@ -10,8 +9,8 @@ import {
   Phone,
   Sparkles,
 } from "lucide-react";
-import Link from "next/link";
 
+import { BackButton } from "@/app/_components";
 import { MobileShell } from "@/app/_components/core";
 import { ROUTES } from "@/router/routes";
 
@@ -69,13 +68,11 @@ export function CoinsRulesScreen() {
     <MobileShell background="#fcf3f4">
       <main className={styles.screen}>
         <header className={styles.header}>
-          <Link
+          <BackButton
             href={ROUTES.sidebar}
-            className={styles.backLink}
+            variant="soft"
             aria-label="Back to sidebar"
-          >
+          />
-            <ArrowLeft size={22} strokeWidth={2.4} aria-hidden="true" />
-          </Link>
 
           <div className={styles.hero}>
             <span className={styles.heroIcon} aria-hidden="true">

src/app/sidebar/components/back-bar.module.css

@@ -1,28 +0,0 @@
-.bar {
-  padding: var(--spacing-md, 12px) 0;
-  display: flex;
-  align-items: center;
-}
-
-.link {
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
-  width: 32px;
-  height: 32px;
-  color: #000000;
-  text-decoration: none;
-  background: none;
-  border: 0;
-  padding: 0;
-  cursor: pointer;
-}
-
-.link:hover {
-  opacity: 0.7;
-}
-
-.icon {
-  color: currentColor;
-  flex-shrink: 0;
-}

src/app/sidebar/components/back-bar.tsx

@@ -1,34 +0,0 @@
-"use client";
-
-import { ChevronLeft } from "lucide-react";
-import Link from "next/link";
-
-import { ROUTES } from "@/router/routes";
-
-import styles from "./back-bar.module.css";
-
-/**
- * 顶部返回栏：图标按钮，链接至聊天页。
- *
- * 视觉规格（与设计稿对齐）：
- *   - 黑色文本（浅色主题下）
- *   - 居左对齐，顶部留白
- */
-export function BackBar() {
-  return (
-    <header className={styles.bar}>
-      <Link
-        href={ROUTES.chat}
-        className={styles.link}
-        aria-label="Back"
-      >
-        <ChevronLeft
-          size={24}
-          strokeWidth={2.5}
-          aria-hidden="true"
-          className={styles.icon}
-        />
-      </Link>
-    </header>
-  );
-}

src/app/sidebar/components/index.ts

@@ -2,7 +2,6 @@
  * @file Automatically generated by barrelsby.
  */
 
-export * from "./back-bar";
 export * from "./sidebar-wallet-card";
 export * from "./user-header";
 export * from "./vip-benefits-card";

src/app/sidebar/components/sidebar-screen.module.css

@@ -49,7 +49,7 @@
 }
 
 .topBar {
-  margin: 4px 0 -2px;
+  margin: 10px 0 -2px;
 }
 
 .hero {

src/app/sidebar/sidebar-screen.tsx

@@ -4,13 +4,13 @@ import { LogOut } from "lucide-react";
 import { signOut } from "next-auth/react";
 import { useRouter } from "next/navigation";
 
+import { BackButton } from "@/app/_components";
 import { MobileShell } from "@/app/_components/core";
 import { ROUTES } from "@/router/routes";
 import { useAuthDispatch, useAuthState } from "@/stores/auth/auth-context";
 import { useUserDispatch, useUserState } from "@/stores/user/user-context";
 
 import {
-  BackBar,
   SidebarWalletCard,
   UserHeader,
   type SidebarUserState,
@@ -56,7 +56,7 @@ export function SidebarScreen() {
         <div className={styles.bgOrbTwo} aria-hidden="true" />
 
         <div className={styles.topBar}>
-          <BackBar />
+          <BackButton href={ROUTES.chat} variant="soft" />
         </div>
 
         <section className={`${styles.userSlot} ${styles.revealOne}`}>