@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;600&display=swap');

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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --border-color: #334155;
    --success-color: #10b981;
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    line-height: 1.6;
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.container {
    width: 100%;
    max-width: 900px;
}

.generator-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    animation: cardAppear 0.6s ease-out;
}

@keyframes cardAppear {
    from {
        opacity: 0;
        transform: scale(0.95) translateY(20px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.layout-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    align-items: start;
}

.password-display {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
    grid-column: 1 / -1;
    animation: slideDown 0.5s ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#passwordOutput {
    flex: 1;
    padding: 1.5rem;
    font-size: 1.5rem;
    min-height: 90px;
    background: rgba(15, 23, 42, 0.5);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', 'SF Mono', 'Monaco', 'Cascadia Code', monospace;
    letter-spacing: 2px;
    transition: all 0.3s ease;
    text-align: center;
    caret-color: transparent;
    cursor: default;
    animation: pulseBorder 3s ease-in-out infinite;
}

@keyframes pulseBorder {
    0%, 100% {
        border-color: var(--border-color);
        box-shadow: 0 0 0 0 rgba(99, 102, 241, 0);
    }
    50% {
        border-color: var(--primary-color);
        box-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
    }
}

#passwordOutput:focus {
    outline: none;
    border-color: var(--primary-color);
    animation: none;
    box-shadow: 0 0 30px rgba(99, 102, 241, 0.5);
}

#passwordOutput::selection {
    background: rgba(99, 102, 241, 0.3);
}

.copy-btn {
    padding: 1rem;
    background: var(--primary-color);
    border: none;
    border-radius: 8px;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    min-width: 48px;
    position: relative;
    overflow: hidden;
}

.copy-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.copy-btn:hover::before {
    width: 300px;
    height: 300px;
}

.copy-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 8px 25px rgba(99, 102, 241, 0.4);
}

.copy-btn:active {
    transform: translateY(0) scale(0.98);
}

.options {
    animation: fadeInLeft 0.6s ease-out 0.2s both;
    margin-bottom: 0;
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.generate-section {
    animation: fadeInRight 0.6s ease-out 0.2s both;
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.option-group {
    margin-bottom: 1.25rem;
}

.option-group label {
    display: block;
    margin-bottom: 0.75rem;
    font-weight: 500;
    color: var(--text-primary);
}

#length {
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: rgba(15, 23, 42, 0.5);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
}

#length::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: all 0.3s ease;
}

#length::-webkit-slider-thumb:hover {
    background: var(--primary-hover);
    transform: scale(1.1);
}

#length::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
    transition: all 0.3s ease;
}

#length::-moz-range-thumb:hover {
    background: var(--primary-hover);
    transform: scale(1.1);
}

#lengthValue {
    color: var(--primary-color);
    font-weight: 600;
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    padding: 0.75rem;
    border-radius: 8px;
    transition: all 0.2s ease;
    position: relative;
}

.checkbox-label::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 4px;
    height: 100%;
    background: var(--primary-color);
    border-radius: 0 4px 4px 0;
    transform: scaleY(0);
    transition: transform 0.2s ease;
}

.checkbox-label:hover {
    background: rgba(99, 102, 241, 0.1);
    transform: translateX(5px);
}

.checkbox-label:hover::before {
    transform: scaleY(1);
}

.checkbox-label input[type="checkbox"]:checked ~ span {
    color: var(--text-primary);
    font-weight: 500;
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.checkbox-label span {
    user-select: none;
    color: var(--text-secondary);
}

.generate-btn {
    width: 100%;
    padding: 1rem;
    font-size: 1.1rem;
    font-weight: 600;
    background: linear-gradient(135deg, var(--primary-color) 0%, #8b5cf6 100%);
    background-size: 200% 200%;
    border: none;
    border-radius: 12px;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
    position: relative;
    overflow: hidden;
    animation: gradientMove 3s ease infinite;
}

@keyframes gradientMove {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.generate-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.generate-btn:hover::before {
    left: 100%;
}

.generate-btn:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 8px 30px rgba(99, 102, 241, 0.5);
    animation: none;
    background-position: 100% 50%;
}

.generate-btn:active {
    transform: translateY(-1px) scale(0.98);
}

.notification {
    margin-top: 1rem;
    padding: 0.75rem;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    opacity: 0;
    transform: translateY(-10px) scale(0.9);
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.notification.show {
    opacity: 1;
    transform: translateY(0) scale(1);
    animation: bounceIn 0.5s ease;
}

@keyframes bounceIn {
    0% {
        transform: scale(0.3) translateY(-20px);
        opacity: 0;
    }
    50% {
        transform: scale(1.1) translateY(0);
    }
    70% {
        transform: scale(0.9);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

.notification.success {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success-color);
    border: 1px solid var(--success-color);
}

.notification.error {
    background: rgba(239, 68, 68, 0.2);
    color: #ef4444;
    border: 1px solid #ef4444;
}


@media (max-width: 768px) {
    .layout-grid {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }
    
    .password-display {
        grid-column: 1;
        margin-bottom: 1.25rem;
    }
}

@media (max-width: 600px) {
    .container {
        max-width: 100%;
    }
    
    .generator-card {
        padding: 1.5rem;
        border-radius: 16px;
    }
    
    #passwordOutput {
        font-size: 1.2rem;
        padding: 1.25rem;
        min-height: 80px;
        letter-spacing: 1.5px;
    }
    
    .layout-grid {
        gap: 1rem;
    }
    
    .option-group {
        margin-bottom: 1rem;
    }
}