:root {
    --primary-color: #4a6fa5;
    --secondary-color: #166088;
    --accent-color: #4fc3f7;
    --background-color: #ffffff;
    --text-color: #333333;
    --border-color: #dddddd;
    --strength-weak: #ff5252;
    --strength-medium: #ffab40;
    --strength-strong: #4caf50;
    --strength-very-strong: #2e7d32;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    padding: 30px;
    width: 100%;
    max-width: 500px;
}

h1 {
    text-align: center;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.password-display {
    display: flex;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    overflow: hidden;
}

.password-display input {
    flex: 1;
    padding: 12px 15px;
    border: none;
    font-size: 16px;
    background-color: #f9f9f9;
}

.password-display input:focus {
    outline: none;
}

#copy-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0 15px;
    cursor: pointer;
    transition: background-color 0.3s;
}

#copy-btn:hover {
    background-color: var(--secondary-color);
}

.controls {
    margin-bottom: 25px;
}

.control-group {
    margin-bottom: 15px;
}

.control-group label {
    display: block;
    margin-bottom: 8px;
    cursor: pointer;
    font-size: 14px;
}

.control-group input[type="checkbox"] {
    margin-right: 8px;
}

.control-group input[type="range"] {
    width: 100%;
    margin-top: 5px;
}

#length {
    margin-bottom: 10px;
}

#length-value {
    font-weight: bold;
    color: var(--primary-color);
}

#generate-btn {
    width: 100%;
    padding: 12px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s;
    margin-top: 10px;
}

#generate-btn:hover {
    background-color: var(--secondary-color);
}

.strength-meter {
    margin-top: 20px;
}

.strength-bar {
    height: 8px;
    background-color: #eee;
    border-radius: 4px;
    margin-bottom: 8px;
    overflow: hidden;
}

.strength-bar::after {
    content: '';
    display: block;
    height: 100%;
    width: 0;
    transition: width 0.3s, background-color 0.3s;
}

.strength-text {
    font-size: 14px;
    text-align: center;
}

#strength-value {
    font-weight: bold;
}

/* Strength meter colors */
.strength-weak::after {
    width: 25%;
    background-color: var(--strength-weak);
}

.strength-medium::after {
    width: 50%;
    background-color: var(--strength-medium);
}

.strength-strong::after {
    width: 75%;
    background-color: var(--strength-strong);
}

.strength-very-strong::after {
    width: 100%;
    background-color: var(--strength-very-strong);
}

/* Tooltip for copy button */
#copy-btn::after {
    content: 'Copied!';
    position: absolute;
    background-color: var(--text-color);
    color: white;
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 12px;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}

#copy-btn.copied::after {
    opacity: 1;
}