style: Add title card background color

content/tools/hardware/mobile-phones/index.md

@@ -47,6 +47,8 @@ A few more tips regarding Android devices and operating system compatibility:
 
 Google Pixel phones are the **only** devices we recommend for purchase. Pixel phones have stronger hardware security than any other Android devices currently on the market, due to proper AVB support for third-party operating systems and Google's custom [Titan](https://security.googleblog.com/2021/10/pixel-6-setting-new-standard-for-mobile.html) security chips acting as the Secure Element.
 
+{{< title-card >}}
+
 **Google Pixel** devices are known to have good security and properly support [Verified Boot](https://source.android.com/security/verifiedboot), even when installing custom operating systems.
 
 Beginning with the **Pixel 8** and **8 Pro**, Pixel devices receive a minimum of 7 years of guaranteed security updates, ensuring a much longer lifespan compared to the 2-5 years competing OEMs typically offer.
@@ -56,6 +58,8 @@ Beginning with the **Pixel 8** and **8 Pro**, Pixel devices receive a minimum of
   {{< card link="https://support.google.com/pixelphone" title="Documentation" icon="document-text" >}}
 {{< /cards >}}
 
+{{< /title-card >}}
+
 ### Hardware Security
 
 Secure Elements like the Titan M2 are more limited than the processor's Trusted Execution Environment (TEE) used by most other phones as they are only used for secrets storage, hardware attestation, and rate limiting, not for running "trusted" programs. Phones without a Secure Element have to use the TEE for *all* of those functions, resulting in a larger attack surface.

content/tools/hardware/security-keys/index.md

@@ -21,6 +21,8 @@ A physical **security key** adds a very strong layer of protection to your onlin
 
 ## Yubico Security Key
 
+{{< title-card >}}
+
 The **Yubico Security Key** series is the most cost-effective hardware security key with FIDO Level 2 certification[^1]. It supports FIDO2/WebAuthn and FIDO Universal 2nd Factor (U2F), and works out of the box with most services that support a security key as a second factor, as well as many password managers.
 
 {{< cards >}}
@@ -28,6 +30,8 @@ The **Yubico Security Key** series is the most cost-effective hardware security
   {{< card link="https://yubico.com/support/terms-conditions/privacy-notice" title="Privacy Policy" icon="eye" >}}
 {{< /cards >}}
 
+{{< /title-card >}}
+
 These keys are available in both USB-C and USB-A variants, and both options support NFC for use with a mobile device as well.
 
 This key provides only basic FIDO2 functionality, but for most people that is all you will need. Some notable features the Security Key series does **not** have include:
@@ -44,6 +48,8 @@ If you need any of those features, you should consider their higher-end [YubiKey
 
 ## YubiKey
 
+{{< title-card >}}
+
 The **YubiKey** series from Yubico are among the most popular security keys with FIDO Level 2 Certification[^1]. The **YubiKey 5 Series** has a wide range of features such as FIDO2/WebAuthn and FIDO U2F, [TOTP and HOTP](https://developers.yubico.com/OATH) authentication, [Personal Identity Verification (PIV)](https://developers.yubico.com/PIV), and [OpenPGP](https://developers.yubico.com/PGP).
 
 {{< cards >}}
@@ -51,6 +57,8 @@ The **YubiKey** series from Yubico are among the most popular security keys with
   {{< card link="https://yubico.com/support/terms-conditions/privacy-notice" title="Privacy Policy" icon="eye" >}}
 {{< /cards >}}
 
+{{< /title-card >}}
+
 The [comparison table](https://yubico.com/store/compare) shows how the YubiKeys compare to each other and to Yubico's [Security Key](#yubico-security-key) series in terms of features and other specifications. One of the benefits of the YubiKey series is that one key can do almost everything you could expect from a hardware security key. We encourage you to take their [quiz](https://yubico.com/quiz) before purchasing in order to make sure you choose the right security key.
 
 YubiKeys can be programmed using the [YubiKey Manager](https://yubico.com/support/download/yubikey-manager) or [YubiKey Personalization Tools](https://yubico.com/support/download/yubikey-personalization-tools). For managing TOTP codes, you can use the [Yubico Authenticator](https://yubico.com/products/yubico-authenticator). All of Yubico's clients are open source.
@@ -63,6 +71,8 @@ For models which [support HOTP and TOTP](https://support.yubico.com/hc/articles/
 
 ## Nitrokey
 
+{{< title-card >}}
+
 **Nitrokey** has a cost-effective security key capable of FIDO2/WebAuthn and FIDO U2F called the **Nitrokey Passkey**. For support for features such as PIV, OpenPGP, and TOTP and HOTP authentication, you need to purchase one of their other keys like the **Nitrokey 3**. Currently, only the **Nitrokey 3A Mini** has [FIDO Level 1 Certification](https://nitrokey.com/news/2024/nitrokey-3a-mini-receives-official-fido2-certification).
 
 {{< cards >}}
@@ -70,6 +80,8 @@ For models which [support HOTP and TOTP](https://support.yubico.com/hc/articles/
   {{< card link="https://nitrokey.com/data-privacy-policy" title="Privacy Policy" icon="eye" >}}
 {{< /cards >}}
 
+{{< /title-card >}}
+
 The [comparison table](https://nitrokey.com/products/nitrokeys#:~:text=The%20Nitrokey%20Family) shows how the different Nitrokey models compare to each other in terms of features and other specifications. Refer to Nitrokey's [documentation](https://docs.nitrokey.com/nitrokeys/features) for more details about the features available on your Nitrokey.
 
 Nitrokey models can be configured using the [Nitrokey app](https://nitrokey.com/download).