:root {
    --bg-color: #000000;
    --primary-text-color: #E0E0E0;
    --secondary-text-color: #A0A0A0;
    --accent-color: #00A9E0; /* A modern teal/blue accent */
    --accent-hover-color: #007FAF;
    --input-bg-color: #1A1A1A;
    --input-border-color: #333333;
    --input-focus-border-color: var(--accent-color);
    --button-text-color: #FFFFFF;
    --redgifs-red: #FF4500; /* For highlighting */
    --success-color: #28a745;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--primary-text-color);
    display: flex;
    justify-content: center;
    align-items: flex-start; /* Align to top for scroll */
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.container {
    width: 100%;
    max-width: 700px;
    padding: 25px 30px;
    background-color: #0D0D0D; /* Slightly off-black for container if pure black feels too flat */
    border-radius: 12px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    font-size: 2.2em;
    font-weight: 700;
    color: var(--primary-text-color);
    margin-bottom: 5px;
}

header p {
    font-size: 1em;
    color: var(--secondary-text-color);
}

.highlight-red {
    color: var(--redgifs-red);
    font-weight: 500;
}

.url-io-container {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.input-section,
.output-section {
    display: flex;
    flex-direction: column;
}

label {
    font-size: 0.95em;
    margin-bottom: 10px;
    color: var(--primary-text-color);
    font-weight: 500;
}

textarea {
    background-color: var(--input-bg-color);
    color: var(--primary-text-color);
    border: 1px solid var(--input-border-color);
    border-radius: 8px;
    padding: 12px 15px;
    font-family: 'Inter', sans-serif;
    font-size: 0.9em;
    resize: vertical;
    min-height: 120px;
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.2);
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

textarea:focus {
    outline: none;
    border-color: var(--input-focus-border-color);
    box-shadow: 0 0 0 3px rgba(0, 169, 224, 0.2); /* Focus ring with accent color */
}

textarea::placeholder {
    color: #666;
}

.action-button {
    background-color: var(--accent-color);
    color: var(--button-text-color);
    border: none;
    border-radius: 8px;
    padding: 12px 20px;
    font-family: 'Inter', sans-serif;
    font-size: 1em;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

.action-button:hover {
    background-color: var(--accent-hover-color);
}

.action-button:active {
    transform: translateY(1px);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.action-button svg {
    transition: transform 0.3s ease-out;
}

#convertBtn:hover svg {
    transform: rotate(-15deg);
}

.copy-button {
    margin-top: 10px;
    background-color: #333; /* Different color for copy */
}
.copy-button:hover {
    background-color: #444;
}

.copy-button.copied {
    background-color: var(--success-color) !important; /* Green for success */
    pointer-events: none; /* Prevent clicking again while in "copied" state */
}

.copy-button.copied .copy-icon {
    display: none;
}
.copy-button.copied .check-icon {
    display: inline-block !important; /* Important to override initial display:none */
}

footer {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid var(--input-border-color);
}

footer p {
    font-size: 0.85em;
    color: var(--secondary-text-color);
}