fix: standardize error display to use showError/hideError helpers

Replace three inconsistent error display patterns with the centralized
showError()/hideError() helpers from helpers.js:

- approval.js: replace direct DOM classList toggling for approve-tx-error
  and approve-sign-error with showError/hideError calls
- addressDetail.js: replace export-privkey-flash direct DOM with
  showError/hideError using renamed export-privkey-error element
- deleteWallet.js: replace delete-wallet-flash direct DOM with
  showError/hideError using renamed delete-wallet-error element
- addWallet.js: replace showFlash() validation errors with dedicated
  add-wallet-error div and showError/hideError calls
- importKey.js: replace showFlash() validation errors with dedicated
  import-key-error div and showError/hideError calls
- index.html: add error divs for add-wallet and import-key views,
  rename export-privkey-flash to export-privkey-error,
  rename delete-wallet-flash to delete-wallet-error,
  remove inconsistent text-red-500 class

Closes #87

src/popup/index.html

@@ -56,34 +56,9 @@
                     < Back
                 </button>
                 <h2 class="font-bold mb-2">Add Wallet</h2>
-
-                <!-- Mode selector tabs -->
-                <div class="flex gap-1 mb-3">
-                    <button
-                        id="tab-mnemonic"
-                        class="border border-border px-2 py-1 cursor-pointer text-xs hover:bg-fg hover:text-bg bg-fg text-bg"
-                    >
-                        Recovery Phrase
-                    </button>
-                    <button
-                        id="tab-privkey"
-                        class="border border-border px-2 py-1 cursor-pointer text-xs hover:bg-fg hover:text-bg"
-                    >
-                        Private Key
-                    </button>
-                    <button
-                        id="tab-xprv"
-                        class="border border-border px-2 py-1 cursor-pointer text-xs hover:bg-fg hover:text-bg"
-                    >
-                        Extended Key (xprv)
-                    </button>
-                </div>
-
-                <!-- Mnemonic form section -->
-                <div id="add-wallet-section-mnemonic">
                 <p class="mb-2">
-                        Enter your 12 or 24 word recovery phrase below, or click
-                        the button to roll the die for a new one.
+                    Enter your 12 or 24 word recovery phrase below, or click the
+                    button to roll the die for a new one.
                 </p>
                 <div class="mb-1 flex justify-end">
                     <button
@@ -106,51 +81,12 @@
                     id="add-wallet-phrase-warning"
                     class="text-xs mb-2 border border-border border-dashed p-2 hidden"
                 >
-                        Write these words down and keep them safe. Anyone with
-                        them can take your funds; if you lose them, your wallet
-                        is gone.
+                    Write these words down and keep them safe. Anyone with them
+                    can take your funds; if you lose them, your wallet is gone.
                 </div>
-                </div>
-
-                <!-- Private key form section -->
-                <div id="add-wallet-section-privkey" class="hidden">
-                    <p class="mb-2">
-                        Paste your private key below. This wallet will have a
-                        single address.
-                    </p>
-                    <div class="mb-2">
-                        <input
-                            type="password"
-                            id="import-private-key"
-                            class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
-                            placeholder="0x..."
-                        />
-                    </div>
-                </div>
-
-                <!-- Extended key (xprv) form section -->
-                <div id="add-wallet-section-xprv" class="hidden">
-                    <p class="mb-2">
-                        Paste your extended private key (xprv) below. This will
-                        import the HD wallet and scan for used addresses.
-                    </p>
-                    <div class="mb-2">
-                        <input
-                            type="password"
-                            id="import-xprv-key"
-                            class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
-                            placeholder="xprv..."
-                        />
-                    </div>
-                </div>
-
-                <!-- Shared password fields -->
                 <div class="mb-2" id="add-wallet-password-section">
                     <label class="block mb-1">Choose a password</label>
-                    <p
-                        class="text-xs text-muted mb-1"
-                        id="add-wallet-password-hint"
-                    >
+                    <p class="text-xs text-muted mb-1">
                         This password encrypts your recovery phrase on this
                         device. You will need it to send funds.
                     </p>
@@ -168,9 +104,69 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
+                <div id="add-wallet-error" class="text-xs mb-2 hidden"></div>
                 <button
                     id="btn-add-wallet-confirm"
                     class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
+                >
+                    Add
+                </button>
+                <div class="mt-3 text-xs text-muted">
+                    Have a private key instead?
+                    <button
+                        id="btn-add-wallet-import-key"
+                        class="underline cursor-pointer bg-transparent border-none text-fg text-xs font-mono p-0"
+                    >
+                        Import private key
+                    </button>
+                </div>
+            </div>
+
+            <!-- ============ IMPORT PRIVATE KEY ============ -->
+            <div id="view-import-key" class="view hidden">
+                <button
+                    id="btn-import-key-back"
+                    class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer mb-2"
+                >
+                    &lt; Back
+                </button>
+                <h2 class="font-bold mb-2">Import Private Key</h2>
+                <p class="mb-2">
+                    Paste your private key below. This wallet will have a single
+                    address.
+                </p>
+                <div class="mb-2">
+                    <input
+                        type="password"
+                        id="import-private-key"
+                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                        placeholder="0x..."
+                    />
+                </div>
+                <div class="mb-2" id="import-key-password-section">
+                    <label class="block mb-1">Choose a password</label>
+                    <p class="text-xs text-muted mb-1">
+                        This password encrypts your private key on this device.
+                        You will need it to send funds.
+                    </p>
+                    <input
+                        type="password"
+                        id="import-key-password"
+                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                    />
+                </div>
+                <div class="mb-2" id="import-key-password-confirm-section">
+                    <label class="block mb-1">Confirm password</label>
+                    <input
+                        type="password"
+                        id="import-key-password-confirm"
+                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                    />
+                </div>
+                <div id="import-key-error" class="text-xs mb-2 hidden"></div>
+                <button
+                    id="btn-import-key-confirm"
+                    class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
                 >
                     Import
                 </button>
@@ -371,7 +367,7 @@
                     transfer all funds from this address. Never share it.
                 </p>
                 <div
-                    id="export-privkey-flash"
+                    id="export-privkey-error"
                     class="text-xs mb-2 hidden"
                 ></div>
                 <div id="export-privkey-password-section" class="mb-2">
@@ -502,6 +498,11 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                         placeholder="Address (0x...) or ENS name"
                     />
+                    <div
+                        id="send-to-error"
+                        class="text-xs"
+                        style="min-height: 1.25rem; color: #cc0000"
+                    ></div>
                 </div>
                 <div class="mb-2">
                     <div class="flex justify-between mb-1">
@@ -939,10 +940,7 @@
                     <strong id="delete-wallet-name"></strong> is permanent. Any
                     funds will be unrecoverable without your recovery phrase.
                 </p>
-                <div
-                    id="delete-wallet-flash"
-                    class="text-xs text-red-500 mb-2 hidden"
-                ></div>
+                <div id="delete-wallet-error" class="text-xs mb-2 hidden"></div>
                 <div class="mb-2">
                     <label class="block mb-1">Password</label>
                     <input

src/popup/index.js

@@ -10,6 +10,7 @@ const { $, showView } = require("./views/helpers");
 const home = require("./views/home");
 const welcome = require("./views/welcome");
 const addWallet = require("./views/addWallet");
+const importKey = require("./views/importKey");
 const addressDetail = require("./views/addressDetail");
 const addressToken = require("./views/addressToken");
 const send = require("./views/send");
@@ -53,6 +54,7 @@ const ctx = {
     renderWalletList,
     doRefreshAndRender,
     showAddWalletView: () => addWallet.show(),
+    showImportKeyView: () => importKey.show(),
     showAddressDetail: () => addressDetail.show(),
     showAddressToken: () => addressToken.show(),
     showAddTokenView: () => addToken.show(),
@@ -207,6 +209,7 @@ async function init() {
 
     welcome.init(ctx);
     addWallet.init(ctx);
+    importKey.init(ctx);
     home.init(ctx);
     addressDetail.init(ctx);
     addressToken.init(ctx);

src/popup/views/addWallet.js

@@ -1,76 +1,41 @@
-const { $, showView, showFlash } = require("./helpers");
+const { $, showView, showFlash, showError, hideError } = require("./helpers");
 const {
     generateMnemonic,
     hdWalletFromMnemonic,
     isValidMnemonic,
-    addressFromPrivateKey,
-    hdWalletFromXprv,
-    isValidXprv,
 } = require("../../shared/wallet");
 const { encryptWithPassword } = require("../../shared/vault");
 const { state, saveState } = require("../../shared/state");
 const { scanForAddresses } = require("../../shared/balances");
 
-let currentMode = "mnemonic";
-
-const MODES = ["mnemonic", "privkey", "xprv"];
-
-const PASSWORD_HINTS = {
-    mnemonic:
-        "This password encrypts your recovery phrase on this device. You will need it to send funds.",
-    privkey:
-        "This password encrypts your private key on this device. You will need it to send funds.",
-    xprv: "This password encrypts your key on this device. You will need it to send funds.",
-};
-
-function switchMode(mode) {
-    currentMode = mode;
-    for (const m of MODES) {
-        $("add-wallet-section-" + m).classList.toggle("hidden", m !== mode);
-        $("tab-" + m).classList.toggle("bg-fg", m === mode);
-        $("tab-" + m).classList.toggle("text-bg", m === mode);
-    }
-    $("add-wallet-password-hint").textContent = PASSWORD_HINTS[mode];
-}
-
 function show() {
     $("wallet-mnemonic").value = "";
-    $("import-private-key").value = "";
-    $("import-xprv-key").value = "";
     $("add-wallet-password").value = "";
     $("add-wallet-password-confirm").value = "";
     $("add-wallet-phrase-warning").classList.add("hidden");
-    switchMode("mnemonic");
+    hideError("add-wallet-error");
     showView("add-wallet");
 }
 
-function validatePassword() {
-    const pw = $("add-wallet-password").value;
-    const pw2 = $("add-wallet-password-confirm").value;
-    if (!pw) {
-        showFlash("Please choose a password.");
-        return null;
-    }
-    if (pw.length < 12) {
-        showFlash("Password must be at least 12 characters.");
-        return null;
-    }
-    if (pw !== pw2) {
-        showFlash("Passwords do not match.");
-        return null;
-    }
-    return pw;
-}
+function init(ctx) {
+    $("btn-generate-phrase").addEventListener("click", () => {
+        $("wallet-mnemonic").value = generateMnemonic();
+        $("add-wallet-phrase-warning").classList.remove("hidden");
+    });
 
-async function importMnemonic(ctx) {
+    $("btn-add-wallet-confirm").addEventListener("click", async () => {
         const mnemonic = $("wallet-mnemonic").value.trim();
         if (!mnemonic) {
-        showFlash("Enter a recovery phrase or press the die to generate one.");
+            showError(
+                "add-wallet-error",
+                "Enter a recovery phrase or press the die to generate one.",
+            );
             return;
         }
         const words = mnemonic.split(/\s+/);
         if (words.length !== 12 && words.length !== 24) {
-        showFlash(
+            showError(
+                "add-wallet-error",
                 "Recovery phrase must be 12 or 24 words. You entered " +
                     words.length +
                     ".",
@@ -78,21 +43,43 @@ async function importMnemonic(ctx) {
             return;
         }
         if (!isValidMnemonic(mnemonic)) {
-        showFlash("Invalid recovery phrase. Check for typos.");
+            showError(
+                "add-wallet-error",
+                "Invalid recovery phrase. Check for typos.",
+            );
+            return;
+        }
+        const pw = $("add-wallet-password").value;
+        const pw2 = $("add-wallet-password-confirm").value;
+        if (!pw) {
+            showError("add-wallet-error", "Please choose a password.");
+            return;
+        }
+        if (pw.length < 12) {
+            showError(
+                "add-wallet-error",
+                "Password must be at least 12 characters.",
+            );
+            return;
+        }
+        if (pw !== pw2) {
+            showError("add-wallet-error", "Passwords do not match.");
             return;
         }
-    const pw = validatePassword();
-    if (!pw) return;
         const { xpub, firstAddress } = hdWalletFromMnemonic(mnemonic);
         const duplicate = state.wallets.find(
             (w) =>
                 w.type === "hd" &&
                 w.addresses[0] &&
-            w.addresses[0].address.toLowerCase() === firstAddress.toLowerCase(),
+                w.addresses[0].address.toLowerCase() ===
+                    firstAddress.toLowerCase(),
         );
         if (duplicate) {
-        showFlash(
-            "This recovery phrase is already added (" + duplicate.name + ").",
+            showError(
+                "add-wallet-error",
+                "This recovery phrase is already added (" +
+                    duplicate.name +
+                    ").",
             );
             return;
         }
@@ -112,6 +99,7 @@ async function importMnemonic(ctx) {
         state.hasWallet = true;
         await saveState();
         ctx.renderWalletList();
+        hideError("add-wallet-error");
         showView("main");
 
         // Scan for used HD addresses beyond index 0.
@@ -132,143 +120,8 @@ async function importMnemonic(ctx) {
         }
 
         ctx.doRefreshAndRender();
-}
-
-async function importPrivateKey(ctx) {
-    const key = $("import-private-key").value.trim();
-    if (!key) {
-        showFlash("Please enter your private key.");
-        return;
-    }
-    let addr;
-    try {
-        addr = addressFromPrivateKey(key);
-    } catch (e) {
-        showFlash("Invalid private key.");
-        return;
-    }
-    const pw = validatePassword();
-    if (!pw) return;
-    const duplicate = state.wallets.find(
-        (w) =>
-            w.type === "key" &&
-            w.addresses[0] &&
-            w.addresses[0].address.toLowerCase() === addr.toLowerCase(),
-    );
-    if (duplicate) {
-        showFlash(
-            "This private key is already added (" + duplicate.name + ").",
-        );
-        return;
-    }
-    const encrypted = await encryptWithPassword(key, pw);
-    const walletNum = state.wallets.length + 1;
-    state.wallets.push({
-        type: "key",
-        name: "Wallet " + walletNum,
-        encryptedSecret: encrypted,
-        addresses: [{ address: addr, balance: "0.0000", tokenBalances: [] }],
-    });
-    state.hasWallet = true;
-    await saveState();
-    ctx.renderWalletList();
-    showView("main");
-
-    ctx.doRefreshAndRender();
-}
-
-async function importXprvKey(ctx) {
-    const xprv = $("import-xprv-key").value.trim();
-    if (!xprv) {
-        showFlash("Please enter your extended private key.");
-        return;
-    }
-    if (!isValidXprv(xprv)) {
-        showFlash("Invalid extended private key.");
-        return;
-    }
-    let result;
-    try {
-        result = hdWalletFromXprv(xprv);
-    } catch (e) {
-        showFlash("Invalid extended private key.");
-        return;
-    }
-    const { xpub, firstAddress } = result;
-    const duplicate = state.wallets.find(
-        (w) =>
-            (w.type === "hd" || w.type === "xprv") &&
-            w.addresses[0] &&
-            w.addresses[0].address.toLowerCase() === firstAddress.toLowerCase(),
-    );
-    if (duplicate) {
-        showFlash("This key is already added (" + duplicate.name + ").");
-        return;
-    }
-    const pw = validatePassword();
-    if (!pw) return;
-    const encrypted = await encryptWithPassword(xprv, pw);
-    const walletNum = state.wallets.length + 1;
-    const wallet = {
-        type: "xprv",
-        name: "Wallet " + walletNum,
-        xpub: xpub,
-        encryptedSecret: encrypted,
-        nextIndex: 1,
-        addresses: [
-            { address: firstAddress, balance: "0.0000", tokenBalances: [] },
-        ],
-    };
-    state.wallets.push(wallet);
-    state.hasWallet = true;
-    await saveState();
-    ctx.renderWalletList();
-    showView("main");
-
-    // Scan for used HD addresses beyond index 0.
-    showFlash("Scanning for addresses...", 30000);
-    const scan = await scanForAddresses(xpub, state.rpcUrl);
-    if (scan.addresses.length > 1) {
-        wallet.addresses = scan.addresses.map((a) => ({
-            address: a.address,
-            balance: "0.0000",
-            tokenBalances: [],
-        }));
-        wallet.nextIndex = scan.nextIndex;
-        await saveState();
-        ctx.renderWalletList();
-        showFlash("Found " + scan.addresses.length + " addresses.");
-    } else {
-        showFlash("Ready.", 1000);
-    }
-
-    ctx.doRefreshAndRender();
-}
-
-function init(ctx) {
-    // Tab click handlers
-    $("tab-mnemonic").addEventListener("click", () => switchMode("mnemonic"));
-    $("tab-privkey").addEventListener("click", () => switchMode("privkey"));
-    $("tab-xprv").addEventListener("click", () => switchMode("xprv"));
-
-    // Generate mnemonic
-    $("btn-generate-phrase").addEventListener("click", () => {
-        $("wallet-mnemonic").value = generateMnemonic();
-        $("add-wallet-phrase-warning").classList.remove("hidden");
     });
 
-    // Import / confirm
-    $("btn-add-wallet-confirm").addEventListener("click", async () => {
-        if (currentMode === "mnemonic") {
-            await importMnemonic(ctx);
-        } else if (currentMode === "privkey") {
-            await importPrivateKey(ctx);
-        } else if (currentMode === "xprv") {
-            await importXprvKey(ctx);
-        }
-    });
-
-    // Back button
     $("btn-add-wallet-back").addEventListener("click", () => {
         if (!state.hasWallet) {
             showView("welcome");
@@ -277,6 +130,11 @@ function init(ctx) {
             showView("main");
         }
     });
+
+    $("btn-add-wallet-import-key").addEventListener(
+        "click",
+        ctx.showImportKeyView,
+    );
 }
 
 module.exports = { init, show };

src/popup/views/addressDetail.js

@@ -2,6 +2,8 @@ const {
     $,
     showView,
     showFlash,
+    showError,
+    hideError,
     balanceLinesForAddress,
     addressDotHtml,
     addressTitle,
@@ -15,7 +17,11 @@ const {
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
-const { updateSendBalance, renderSendTokenSelect } = require("./send");
+const {
+    updateSendBalance,
+    renderSendTokenSelect,
+    resetSendValidation,
+} = require("./send");
 const { log } = require("../../shared/log");
 const makeBlockie = require("ethereum-blockies-base64");
 const { decryptWithPassword } = require("../../shared/vault");
@@ -259,6 +265,7 @@ function init(_ctx) {
         $("send-token").classList.remove("hidden");
         $("send-token-static").classList.add("hidden");
         updateSendBalance();
+        resetSendValidation();
         showView("send");
     });
 
@@ -305,8 +312,7 @@ function init(_ctx) {
         $("export-privkey-address").textContent = addr.address;
         $("export-privkey-address").dataset.full = addr.address;
         $("export-privkey-password").value = "";
-        $("export-privkey-flash").classList.add("hidden");
-        $("export-privkey-flash").textContent = "";
+        hideError("export-privkey-error");
         $("export-privkey-password-section").classList.remove("hidden");
         $("export-privkey-result").classList.add("hidden");
         $("export-privkey-value").textContent = "";
@@ -316,8 +322,7 @@ function init(_ctx) {
     $("btn-export-privkey-confirm").addEventListener("click", async () => {
         const password = $("export-privkey-password").value;
         if (!password) {
-            $("export-privkey-flash").textContent = "Password is required.";
-            $("export-privkey-flash").classList.remove("hidden");
+            showError("export-privkey-error", "Password is required.");
             return;
         }
         const wallet = state.wallets[state.selectedWallet];
@@ -335,10 +340,9 @@ function init(_ctx) {
             $("export-privkey-password-section").classList.add("hidden");
             $("export-privkey-value").textContent = privateKey;
             $("export-privkey-result").classList.remove("hidden");
-            $("export-privkey-flash").classList.add("hidden");
+            hideError("export-privkey-error");
         } catch {
-            $("export-privkey-flash").textContent = "Wrong password.";
-            $("export-privkey-flash").classList.remove("hidden");
+            showError("export-privkey-error", "Wrong password.");
         }
     });
 

src/popup/views/addressToken.js

@@ -23,7 +23,11 @@ const {
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
-const { updateSendBalance, renderSendTokenSelect } = require("./send");
+const {
+    updateSendBalance,
+    renderSendTokenSelect,
+    resetSendValidation,
+} = require("./send");
 const { log } = require("../../shared/log");
 const makeBlockie = require("ethereum-blockies-base64");
 
@@ -372,6 +376,7 @@ function init(_ctx) {
             });
         }
         updateSendBalance();
+        resetSendValidation();
         showView("send");
     });
 

src/popup/views/approval.js

@@ -4,6 +4,8 @@ const {
     addressTitle,
     escapeHtml,
     showView,
+    showError,
+    hideError,
 } = require("./helpers");
 const { state, saveState } = require("../../shared/state");
 const { formatEther, formatUnits, Interface, toUtf8String } = require("ethers");
@@ -342,7 +344,7 @@ function showSignApproval(details) {
     }
 
     $("approve-sign-password").value = "";
-    $("approve-sign-error").classList.add("hidden");
+    hideError("approve-sign-error");
     $("btn-approve-sign").disabled = false;
     $("btn-approve-sign").classList.remove("text-muted");
 
@@ -407,11 +409,10 @@ function init(ctx) {
     $("btn-approve-tx").addEventListener("click", () => {
         const password = $("approve-tx-password").value;
         if (!password) {
-            $("approve-tx-error").textContent = "Please enter your password.";
-            $("approve-tx-error").classList.remove("hidden");
+            showError("approve-tx-error", "Please enter your password.");
             return;
         }
-        $("approve-tx-error").classList.add("hidden");
+        hideError("approve-tx-error");
         $("btn-approve-tx").disabled = true;
         $("btn-approve-tx").classList.add("text-muted");
 
@@ -447,11 +448,10 @@ function init(ctx) {
     $("btn-approve-sign").addEventListener("click", () => {
         const password = $("approve-sign-password").value;
         if (!password) {
-            $("approve-sign-error").textContent = "Please enter your password.";
-            $("approve-sign-error").classList.remove("hidden");
+            showError("approve-sign-error", "Please enter your password.");
             return;
         }
-        $("approve-sign-error").classList.add("hidden");
+        hideError("approve-sign-error");
         $("btn-approve-sign").disabled = true;
         $("btn-approve-sign").classList.add("text-muted");
 
@@ -469,8 +469,7 @@ function init(ctx) {
                 } else {
                     const msg =
                         (response && response.error) || "Signing failed.";
-                    $("approve-sign-error").textContent = msg;
-                    $("approve-sign-error").classList.remove("hidden");
+                    showError("approve-sign-error", msg);
                     $("btn-approve-sign").disabled = false;
                     $("btn-approve-sign").classList.remove("text-muted");
                 }

src/popup/views/confirmTx.js

@@ -14,6 +14,7 @@ const {
     showError,
     hideError,
     showView,
+    showFlash,
     addressTitle,
     addressDotHtml,
     escapeHtml,
@@ -95,11 +96,22 @@ function show(txInfo) {
     // Token contract section (ERC-20 only)
     const tokenSection = $("confirm-token-section");
     if (isErc20) {
+        const dot = addressDotHtml(txInfo.token);
         const link = etherscanTokenLink(txInfo.token);
         $("confirm-token-contract").innerHTML =
-            escapeHtml(txInfo.token) +
-            ` <a href="${link}" target="_blank" rel="noopener" class="inline-flex items-center">${EXT_ICON}</a>`;
+            `<div class="flex items-center">${dot}` +
+            `<span class="break-all underline decoration-dashed cursor-pointer" data-copy="${escapeHtml(txInfo.token)}">${escapeHtml(txInfo.token)}</span>` +
+            `<a href="${link}" target="_blank" rel="noopener" class="inline-flex items-center">${EXT_ICON}</a>` +
+            `</div>`;
         tokenSection.classList.remove("hidden");
+        // Attach click-to-copy on the contract address
+        const copyEl = tokenSection.querySelector("[data-copy]");
+        if (copyEl) {
+            copyEl.onclick = () => {
+                navigator.clipboard.writeText(copyEl.dataset.copy);
+                showFlash("Copied!");
+            };
+        }
     } else {
         tokenSection.classList.add("hidden");
     }

src/popup/views/deleteWallet.js

@@ -1,4 +1,4 @@
-const { $, showView, showFlash } = require("./helpers");
+const { $, showView, showFlash, showError, hideError } = require("./helpers");
 const { state, saveState } = require("../../shared/state");
 const { decryptWithPassword } = require("../../shared/vault");
 
@@ -11,8 +11,7 @@ function show(walletIdx) {
     $("delete-wallet-name").textContent =
         wallet.name || "Wallet " + (walletIdx + 1);
     $("delete-wallet-password").value = "";
-    $("delete-wallet-flash").textContent = "";
-    $("delete-wallet-flash").classList.add("hidden");
+    hideError("delete-wallet-error");
     showView("delete-wallet-confirm");
 }
 
@@ -27,16 +26,15 @@ function init(_ctx) {
     $("btn-delete-wallet-confirm").addEventListener("click", async () => {
         const pw = $("delete-wallet-password").value;
         if (!pw) {
-            $("delete-wallet-flash").textContent =
-                "Please enter your password.";
-            $("delete-wallet-flash").classList.remove("hidden");
+            showError("delete-wallet-error", "Please enter your password.");
             return;
         }
 
         if (deleteWalletIndex === null) {
-            $("delete-wallet-flash").textContent =
-                "No wallet selected for deletion.";
-            $("delete-wallet-flash").classList.remove("hidden");
+            showError(
+                "delete-wallet-error",
+                "No wallet selected for deletion.",
+            );
             return;
         }
 
@@ -47,8 +45,7 @@ function init(_ctx) {
         try {
             await decryptWithPassword(wallet.encryptedSecret, pw);
         } catch (_e) {
-            $("delete-wallet-flash").textContent = "Wrong password.";
-            $("delete-wallet-flash").classList.remove("hidden");
+            showError("delete-wallet-error", "Wrong password.");
             return;
         }
 

src/popup/views/helpers.js

@@ -13,6 +13,7 @@ const { state, saveState } = require("../../shared/state");
 const VIEWS = [
     "welcome",
     "add-wallet",
+    "import-key",
     "main",
     "address",
     "address-token",

src/popup/views/home.js

@@ -11,7 +11,11 @@ const {
     truncateMiddle,
 } = require("./helpers");
 const { state, saveState, currentAddress } = require("../../shared/state");
-const { updateSendBalance, renderSendTokenSelect } = require("./send");
+const {
+    updateSendBalance,
+    renderSendTokenSelect,
+    resetSendValidation,
+} = require("./send");
 const { deriveAddressFromXpub } = require("../../shared/wallet");
 const {
     formatUsd,
@@ -235,7 +239,7 @@ function render(ctx) {
         html += `<div>`;
         html += `<div class="flex justify-between items-center bg-section py-1 px-2" style="margin:0 -0.5rem">`;
         html += `<span class="font-bold cursor-pointer wallet-name underline decoration-dashed" data-wallet="${wi}">${wallet.name}</span>`;
-        if (wallet.type === "hd" || wallet.type === "xprv") {
+        if (wallet.type === "hd") {
             html += `<button class="btn-add-address border border-border px-1 hover:bg-fg hover:text-bg cursor-pointer text-xs" data-wallet="${wi}" title="Add another address to this wallet">+</button>`;
         }
         html += `</div>`;
@@ -388,6 +392,7 @@ function init(ctx) {
         $("send-token-static").classList.add("hidden");
         renderSendTokenSelect(addr);
         updateSendBalance();
+        resetSendValidation();
         showView("send");
     });
 

src/popup/views/importKey.js

@@ -0,0 +1,73 @@
+const { $, showView, showError, hideError } = require("./helpers");
+const { addressFromPrivateKey } = require("../../shared/wallet");
+const { encryptWithPassword } = require("../../shared/vault");
+const { state, saveState } = require("../../shared/state");
+
+function show() {
+    $("import-private-key").value = "";
+    $("import-key-password").value = "";
+    $("import-key-password-confirm").value = "";
+    hideError("import-key-error");
+    showView("import-key");
+}
+
+function init(ctx) {
+    $("btn-import-key-confirm").addEventListener("click", async () => {
+        const key = $("import-private-key").value.trim();
+        if (!key) {
+            showError("import-key-error", "Please enter your private key.");
+            return;
+        }
+        let addr;
+        try {
+            addr = addressFromPrivateKey(key);
+        } catch (e) {
+            showError("import-key-error", "Invalid private key.");
+            return;
+        }
+        const pw = $("import-key-password").value;
+        const pw2 = $("import-key-password-confirm").value;
+        if (!pw) {
+            showError("import-key-error", "Please choose a password.");
+            return;
+        }
+        if (pw.length < 12) {
+            showError(
+                "import-key-error",
+                "Password must be at least 12 characters.",
+            );
+            return;
+        }
+        if (pw !== pw2) {
+            showError("import-key-error", "Passwords do not match.");
+            return;
+        }
+        const encrypted = await encryptWithPassword(key, pw);
+        const walletNum = state.wallets.length + 1;
+        state.wallets.push({
+            type: "key",
+            name: "Wallet " + walletNum,
+            encryptedSecret: encrypted,
+            addresses: [
+                { address: addr, balance: "0.0000", tokenBalances: [] },
+            ],
+        });
+        state.hasWallet = true;
+        await saveState();
+        ctx.renderWalletList();
+        showView("main");
+
+        ctx.doRefreshAndRender();
+    });
+
+    $("btn-import-key-back").addEventListener("click", () => {
+        if (!state.hasWallet) {
+            showView("welcome");
+        } else {
+            ctx.renderWalletList();
+            showView("main");
+        }
+    });
+}
+
+module.exports = { init, show };

src/popup/views/send.js

@@ -11,6 +11,107 @@ const { state, currentAddress } = require("../../shared/state");
 let ctx;
 const { getProvider } = require("../../shared/balances");
 const { KNOWN_SYMBOLS, resolveSymbol } = require("../../shared/tokenList");
+const { getAddress } = require("ethers");
+
+const ZERO_ADDRESS = "0x0000000000000000000000000000000000000000";
+
+/**
+ * Validate a destination address string.
+ * Returns { valid: true } or { valid: false, error: "..." }.
+ */
+function validateToAddress(value) {
+    const v = value.trim();
+    if (!v) return { valid: false, error: "" };
+
+    // ENS names: contains a dot and doesn't start with 0x
+    if (v.includes(".") && !v.startsWith("0x")) {
+        // Basic ENS format check: at least one label before and after dot
+        if (/^[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)+$/.test(v)) {
+            return { valid: true };
+        }
+        return {
+            valid: false,
+            error: "Please enter a valid ENS name.",
+        };
+    }
+
+    // Must look like an Ethereum address
+    if (!/^0x[0-9a-fA-F]{40}$/.test(v)) {
+        return {
+            valid: false,
+            error: "Please enter a valid Ethereum address.",
+        };
+    }
+
+    // Reject zero address
+    if (v.toLowerCase() === ZERO_ADDRESS) {
+        return {
+            valid: false,
+            error: "Sending to the zero address is not allowed.",
+        };
+    }
+
+    // EIP-55 checksum validation: all-lowercase is ok, otherwise must match checksum
+    if (v !== v.toLowerCase()) {
+        try {
+            const checksummed = getAddress(v);
+            if (checksummed !== v) {
+                return {
+                    valid: false,
+                    error: "Address checksum is invalid. Please double-check the address.",
+                };
+            }
+        } catch {
+            return {
+                valid: false,
+                error: "Address checksum is invalid. Please double-check the address.",
+            };
+        }
+    }
+
+    // Warn if sending to own address
+    const addr = currentAddress();
+    if (addr && v.toLowerCase() === addr.address.toLowerCase()) {
+        // Allow but will warn — we return valid with a warning
+        return {
+            valid: true,
+            warning: "This is your own address. Are you sure?",
+        };
+    }
+
+    return { valid: true };
+}
+
+function updateToValidation() {
+    const input = $("send-to");
+    const errorEl = $("send-to-error");
+    const btn = $("btn-send-review");
+    const value = input.value.trim();
+
+    if (!value) {
+        errorEl.textContent = "";
+        btn.disabled = true;
+        btn.classList.add("opacity-50");
+        return;
+    }
+
+    const result = validateToAddress(value);
+    if (!result.valid) {
+        errorEl.textContent = result.error;
+        errorEl.style.color = "#cc0000";
+        btn.disabled = true;
+        btn.classList.add("opacity-50");
+    } else if (result.warning) {
+        errorEl.textContent = result.warning;
+        errorEl.style.color = "#b8860b";
+        btn.disabled = false;
+        btn.classList.remove("opacity-50");
+    } else {
+        errorEl.textContent = "";
+        btn.disabled = false;
+        btn.classList.remove("opacity-50");
+    }
+}
 
 const EXT_ICON =
     `<span style="display:inline-block;width:10px;height:10px;margin-left:4px;vertical-align:middle">` +
@@ -88,6 +189,13 @@ function init(_ctx) {
     ctx = _ctx;
     $("send-token").addEventListener("change", updateSendBalance);
 
+    // Initial state: disable review button until address is entered
+    $("btn-send-review").disabled = true;
+    $("btn-send-review").classList.add("opacity-50");
+
+    // Validate address on input
+    $("send-to").addEventListener("input", updateToValidation);
+
     $("btn-send-review").addEventListener("click", async () => {
         const to = $("send-to").value.trim();
         const amount = $("send-amount").value.trim();
@@ -95,6 +203,15 @@ function init(_ctx) {
             showFlash("Please enter a recipient address.");
             return;
         }
+
+        // Re-validate before proceeding
+        const validation = validateToAddress(to);
+        if (!validation.valid) {
+            showFlash(
+                validation.error || "Please enter a valid Ethereum address.",
+            );
+            return;
+        }
         if (!amount || isNaN(parseFloat(amount)) || parseFloat(amount) <= 0) {
             showFlash("Please enter a valid amount.");
             return;
@@ -159,4 +276,19 @@ function init(_ctx) {
     });
 }
 
-module.exports = { init, updateSendBalance, renderSendTokenSelect };
+function resetSendValidation() {
+    const errorEl = $("send-to-error");
+    const btn = $("btn-send-review");
+    if (errorEl) errorEl.textContent = "";
+    if (btn) {
+        btn.disabled = true;
+        btn.classList.add("opacity-50");
+    }
+}
+
+module.exports = {
+    init,
+    updateSendBalance,
+    renderSendTokenSelect,
+    resetSendValidation,
+};

src/shared/wallet.js

@@ -24,26 +24,6 @@ function hdWalletFromMnemonic(mnemonic) {
     return { xpub, firstAddress };
 }
 
-function hdWalletFromXprv(xprv) {
-    const root = HDNodeWallet.fromExtendedKey(xprv);
-    if (!root.privateKey) {
-        throw new Error("Not an extended private key (xprv).");
-    }
-    const node = root.derivePath("44'/60'/0'/0");
-    const xpub = node.neuter().extendedKey;
-    const firstAddress = node.deriveChild(0).address;
-    return { xpub, firstAddress };
-}
-
-function isValidXprv(key) {
-    try {
-        const node = HDNodeWallet.fromExtendedKey(key);
-        return !!node.privateKey;
-    } catch {
-        return false;
-    }
-}
-
 function addressFromPrivateKey(key) {
     const w = new Wallet(key);
     return w.address;
@@ -58,11 +38,6 @@ function getSignerForAddress(walletData, addrIndex, decryptedSecret) {
         );
         return node.deriveChild(addrIndex);
     }
-    if (walletData.type === "xprv") {
-        const root = HDNodeWallet.fromExtendedKey(decryptedSecret);
-        const node = root.derivePath("44'/60'/0'/0");
-        return node.deriveChild(addrIndex);
-    }
     return new Wallet(decryptedSecret);
 }
 
@@ -74,8 +49,6 @@ module.exports = {
     generateMnemonic,
     deriveAddressFromXpub,
     hdWalletFromMnemonic,
-    hdWalletFromXprv,
-    isValidXprv,
     addressFromPrivateKey,
     getSignerForAddress,
     isValidMnemonic,