* {
     padding: 0;
     margin: 0;
     box-sizing: border-box;
 }

 :root {
     --clr-bg: #0F1115;
     --clr-surface: #182025;
     --clr-surface-alt: #1E2A30;
     --clr-border: #2A353B;
     --clr-text: #E6EEF0;
     --clr-text-muted: #7E8A92;
     --clr-accent: #3BBF8A;
     --clr-accent-alt: #7C5CFF;
     --clr-danger: #FF5252;
     --clr-badge: #CFAF52;
     --radius: 14px;
     --shadow: 0 4px 16px -4px rgba(0, 0, 0, .55), 0 0 0 1px #1C262B;
 }

 body {
     font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
     background-color: var(--clr-bg);
     color: var(--clr-text);
 }

 .center {
     text-align: center;
     padding: 20px 0 10px 0;
 }

 .open-button {
     background: var(--clr-accent);
     color: #071712;
     border: none;
     padding: .9rem 1.6rem;
     font-size: 1.5rem;
     border-radius: 8px;
     cursor: pointer;
     margin-left: 50px;
     transition: background .25s, box-shadow .25s;
 }

 button:hover {
     background: var(--clr-accent-alt);
     color: #fff;
     box-shadow: 0 0 0 3px #7c5cff33;
 }

 .container {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(200px, 300px));
     justify-content: center;
     gap: 1.5rem;
     padding: 1.5rem;
 }

 .book {
     padding: 1rem;
     background: var(--clr-surface);
     border: 1px solid var(--clr-border);
     border-radius: var(--radius);
     box-shadow: var(--shadow);
     display: flex;
     flex-direction: column;
     justify-content: end;
     gap: .5rem;
     border-left: 5px solid var(--clr-accent);
     font-size: 1.3rem;
     line-height: 2rem;

     .title {
         font-weight: 600;
         font-size: 1.7rem;
         align-self: flex-start;
     }
 }

 .book .btn {
     margin-top: 1.2rem;
     background: var(--clr-accent);
     color: #071712;
     border: none;
     padding: .55rem;
     font-size: 1rem;
     border-radius: 8px;
     cursor: pointer;
     transition: background .25s, box-shadow .25s;

     &.toggle-read:hover {
         background: var(--clr-accent-alt);
         color: #fff;
         box-shadow: 0 0 0 3px #7c5cff33;
     }
 }

 .form-popup {
     display: none;
     position: fixed;
     inset: 0;
     z-index: 50;
     background: rgba(0, 0, 0, .55);
     backdrop-filter: blur(3px);
     padding: 1rem;
     align-items: center;
     justify-content: center;
 }

 .form-container {
     width: min(360px, 100%);
     background: var(--clr-surface);
     border: 1px solid var(--clr-border);
     border-radius: var(--radius);
     padding: 1rem 1.1rem 1.15rem;
     display: flex;
     flex-direction: column;
     gap: .75rem;
     font-size: .9rem;
 }

 .form-container h3 {
     margin: 0 0 .35rem;
     font-size: 1.05rem;
 }

 .form-fields {
     display: flex;
     flex-direction: column;
     gap: .65rem;
 }

 .form-row {
     display: flex;
     flex-direction: column;
     gap: .35rem;
 }

 .form-row.inline {
     flex-direction: row;
     gap: .65rem;
 }

 .form-row.inline>* {
     flex: 1;
 }

 .form-container label {
     font-size: .65rem;
     font-weight: 600;
     letter-spacing: .5px;
     text-transform: uppercase;
     color: var(--clr-text-muted);
 }

 .form-container input[type=text],
 .form-container input[type=number] {
     width: 100%;
     background: #1d272c;
     color: var(--clr-text);
     padding: .55rem .65rem;
     border-radius: 8px;
 }

 .form-container input[type=text]:focus,
 .form-container input[type=number]:focus {
     outline: 2px solid var(--clr-accent);
     outline-offset: 0;
     border-color: var(--clr-accent);
 }

 .checkbox-row {
     display: flex;
     align-items: center;
     gap: .5rem;
     font-size: .75rem;
 }

 .checkbox-row input[type=checkbox] {
     width: 16px;
     height: 16px;
     accent-color: var(--clr-accent);
 }

 input:hover {
     border-color: black;
 }

 input.invalid {
     border-color: #dc2626;
 }

 input.valid {
     border-color: #16a34a;
 }

 .error-message {
     color: var(--clr-danger);
     font-size: 0.9em;
 }

 .checkbox-row label {
     margin: 0;
     font-size: .75rem;
     font-weight: 500;
     text-transform: none;
     letter-spacing: .3px;
     color: var(--clr-text);
 }

 .form-actions {
     display: flex;
     gap: .6rem;
     margin-top: .25rem;
 }

 .form-container .btn {
     flex: 1;
     background: var(--clr-accent);
     color: #071712;
     border: none;
     padding: .65rem .9rem;
     font-weight: 600;
     font-size: .75rem;
     letter-spacing: .4px;
     border-radius: 8px;
     cursor: pointer;
 }

 .form-container .btn:hover {
     background: var(--clr-accent-alt);
     color: #fff;
 }

 .form-container .cancel,
 .remove-book {
     background: var(--clr-danger);
     color: #fff;
 }

 .form-container .cancel:hover,
 .remove-book:hover {
     background: #ff3131;
 }