:root {
    --bg-color: #f0f0f0;
    --text-color: #333;
    --header-bg-color: #ddd;
    --header-color: hotpink;
    --page-bg-color: #ffffff;
    --page-shadow-color: rgba(0, 0, 0, 0.1);
    --select-bg-color: #e9e9e9;
    --select-text-color: #333;
    --select-border-color: #ccc;
    --select-focus-border-color: #0078d4;
    --select-focus-shadow-color: rgba(0, 120, 212, 0.3);
    --color-item-light-text: #111;
    --color-item-dark-text: #fff;
    --color-item-text-hover-bg: rgba(0, 0, 0, 0.1);
    --notification-bg-color: #4caf50;
    --notification-fail-bg-color: #e53935;
    --fieldset-border-color: #ddd;
    --legend-text-color: #555;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #ccc;
    --header-bg-color: #333;
    --header-color: hotpink;
    --page-bg-color: #222;
    --page-shadow-color: rgba(0, 0, 0, 0.3);
    --select-bg-color: #333;
    --select-text-color: #eee;
    --select-border-color: #555;
    --select-focus-border-color: lightskyblue;
    --select-focus-shadow-color: rgba(135, 206, 250, 0.3);
    --color-item-text-hover-bg: rgba(255, 255, 255, 0.1);
    --fieldset-border-color: #444;
    --legend-text-color: #aaa;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg-color: #1a1a1a;
        --text-color: #ccc;
        --header-bg-color: #333;
        --header-color: hotpink;
        --page-bg-color: #222;
        --page-shadow-color: rgba(0, 0, 0, 0.3);
        --select-bg-color: #333;
        --select-text-color: #eee;
        --select-border-color: #555;
        --select-focus-border-color: lightskyblue;
        --select-focus-shadow-color: rgba(135, 206, 250, 0.3);
        --color-item-text-hover-bg: rgba(255, 255, 255, 0.1);
        --fieldset-border-color: #444;
        --legend-text-color: #aaa;
    }
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 20px;
    font-size: 16px;
    transition: background-color 0.3s, color 0.3s;
}

header {
    align-items: center;
    border-radius: 4px;
    display: flex;
    justify-content: space-between;
    margin: 10px auto 30px;
    max-width: 1280px;
    /* --- Styles for Sticky Header --- */
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: var(--header-bg-color);
    padding: 10px 20px;
    box-shadow: 0 4px 12px var(--page-shadow-color);
    transition: background-color 0.3s;
}

header h1 {
    color: var(--header-color);
    font-family: "Source Code Pro", Consolas, "Courier New", Courier, monospace;
    letter-spacing: 4px;
    margin: 0;
    font-size: 1.8em;
}

.controls-container {
    display: flex;
    align-items: center;
}

.controls-container label {
    margin-right: 10px;
    font-size: 0.9em;
}

.controls-container select + label {
    margin-left: 20px;
}

.controls-container select {
    padding: 8px 12px;
    border-radius: 4px;
    border: 1px solid var(--select-border-color);
    background-color: var(--select-bg-color);
    color: var(--select-text-color);
    font-size: 0.9em;
    cursor: pointer;
}

.controls-container select:focus {
    outline: none;
    border-color: var(--select-focus-border-color);
    box-shadow: 0 0 0 2px var(--select-focus-shadow-color);
}

.page-container {
    max-width: 1280px;
    margin: 0 auto 20px;
    padding: 10px 20px 20px;
    background-color: var(--page-bg-color);
    border-radius: 4px;
    box-shadow: 0 4px 12px var(--page-shadow-color);
    transition: background-color 0.3s;
}

fieldset {
    border: 1px solid var(--fieldset-border-color);
    border-radius: 4px;
    padding: 15px;
    margin: 0;
}

legend {
    font-size: 1.2em;
    font-weight: 600;
    color: var(--legend-text-color);
    padding: 0 10px;
    margin-left: 5px;
    display: flex;
    align-items: center;
}

.legend-actions {
    font-size: 0.8em;
    font-weight: normal;
    margin-left: 15px;
    color: var(--select-focus-border-color);
    white-space: nowrap;
}

.legend-copy-action {
    cursor: pointer;
    transition: color 0.2s, transform 0.2s ease-in-out;
    display: inline-block;
}

.legend-copy-action:hover {
    text-decoration: underline;
    color: var(--header-color);
    transform: scale(1.05);
}

.color-list {
    list-style: none;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(245px, 1fr));
    gap: 15px;
}

.color-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 15px;
    border-radius: 4px;
    transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
    cursor: default;
    will-change: transform;
}

.color-item:hover {
    transform: scale(1.02);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

.copy-icon {
    width: 24px;
    height: 24px;
    pointer-events: none;
    margin-left: 4px;
}

.color-item.light-bg {
    color: var(--color-item-light-text);
}

.color-item.dark-bg {
    color: var(--color-item-dark-text);
}

.color-item.dark-bg .copy-icon {
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.5));
}

.color-item.light-bg .copy-icon {
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.2));
}

.color-info {
    flex-grow: 1;
    font-family: "Source Code Pro", Consolas, "Courier New", Courier, monospace;
    font-size: 0.95em;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.color-hex {
    white-space: nowrap;
}

.color-swatch-action {
    cursor: pointer;
    padding: 0 6px; /* Vertical padding removed to fix height */
    border-radius: 4px;
    transition: background-color 0.2s ease-in-out;
    white-space: nowrap;
    display: flex;
    align-items: center;
    height: 24px; /* Ensure consistent height matching the icon */
}

.color-swatch-action:hover {
    background-color: var(--color-item-text-hover-bg);
}

.color-copy-group {
    /* This class now only controls the show/hide animation */
    transition: max-width 0.4s ease-in-out, opacity 0.3s ease-in-out, margin-left 0.4s ease-in-out;
    overflow: hidden;
    opacity: 0;
    max-width: 0;
    margin-left: 0;
}

.color-item:hover .color-copy-group {
    opacity: 1;
    max-width: 12em;
    margin-left: 1ch;
}

.color-copy-group:hover {
    background-color: var(--color-item-text-hover-bg);
}

.copy-notification {
    position: fixed;
    background-color: var(--notification-bg-color);
    color: white;
    padding: 10px 20px;
    border-radius: 4px;
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s ease-in-out, transform 0.3s ease-in-out;
    pointer-events: none;
    transform: translate(-50%, -50%);
    white-space: nowrap;
}

.copy-notification.show {
    opacity: 1;
    transform: translate(-50%, calc(-100% - 10px));
}

.copy-notification.hide {
    opacity: 0;
    transform: translate(-50%, -50%);
}