:root {
    --bg-color: #0a0a0a;
    --card-bg: rgba(255, 255, 255, 0.05);
    --text-primary: #ffffff;
    --text-secondary: #94a3b8;
    --accent-primary: #3b82f6;
    --accent-secondary: #8b5cf6;
    --accent-glow: rgba(59, 130, 246, 0.5);
    --success: #10b981;
    --border-color: rgba(255, 255, 255, 0.1);
    --font-ui: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-ui);
    min-height: 100vh;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    position: relative;
}

/* Background Glow Effect */
.background-glow {
    position: absolute;
    top: -20%;
    left: -20%;
    width: 140%;
    height: 140%;
    background: radial-gradient(circle at 50% 50%, rgba(59, 130, 246, 0.15), transparent 60%);
    z-index: -1;
    pointer-events: none;
}

.container {
    width: 100%;
    max-width: 500px;
    padding: 1rem;
    text-align: center;
}

header {
    margin-bottom: 1.5rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.05em;
    margin-bottom: 0.5rem;
}

.gradient-text {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 300;
}

/* Generator Card */
.generator-card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 1.5rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

/* Password Display */
.password-display-container {
    position: relative;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.password-display-container:focus-within {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

#password-output {
    width: 100%;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 1.25rem;
    padding: 1rem;
    outline: none;
}

#copy-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 1rem;
    cursor: pointer;
    transition: color 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

#copy-btn:hover {
    color: var(--text-primary);
}

#copy-btn.copied {
    color: var(--success);
}

/* Controls */
.controls {
    margin-bottom: 1.5rem;
    text-align: left;
}

.length-control {
    margin-bottom: 1rem;
}

.length-control label {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-secondary);
}

input[type="range"] {
    width: 100%;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    outline: none;
    -webkit-appearance: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    background: var(--accent-primary);
    border-radius: 50%;
    cursor: pointer;
    transition: transform 0.1s ease, box-shadow 0.1s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: 0 0 10px var(--accent-glow);
}

/* Options Grid */
.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.checkbox-container {
    display: flex;
    align-items: center;
    cursor: pointer;
    font-size: 0.9rem;
    color: var(--text-secondary);
    user-select: none;
    transition: color 0.2s ease;
}

.checkbox-container:hover {
    color: var(--text-primary);
}

.checkbox-container input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

.checkmark {
    position: relative;
    height: 20px;
    width: 20px;
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    margin-right: 10px;
    transition: all 0.2s ease;
}

.checkbox-container:hover input ~ .checkmark {
    border-color: var(--text-secondary);
}

.checkbox-container input:checked ~ .checkmark {
    background-color: var(--accent-primary);
    border-color: var(--accent-primary);
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
    left: 6px;
    top: 2px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.checkbox-container input:checked ~ .checkmark:after {
    display: block;
}

.checkbox-container input:disabled ~ .checkmark {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Generate Button */
#generate-btn {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    border: none;
    border-radius: 12px;
    color: white;
    font-family: var(--font-ui);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 4px 15px var(--accent-glow);
}

#generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--accent-glow);
}

#generate-btn:active {
    transform: translateY(0);
}

/* Footer */
.made-by {
    margin-top: 2rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
    opacity: 0.8;
}

.made-by a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
    border-bottom: 1px dotted var(--border-color);
}

.made-by a:hover {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
}

.heart {
    color: #ef4444;
    display: inline-block;
    animation: heartbeat 1.5s infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.2); }
}

@media (max-width: 480px) {
    .options-grid {
        grid-template-columns: 1fr;
    }
}