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

body {
    background-color: #0f172a;
    color: #f8fafc;
    min-height: 100vh;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.container {
    max-width: 900px;
    width: 100%;
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
}

@media (min-width: 768px) {
    .container {
        grid-template-columns: 1fr 1fr;
    }
}

.header {
    text-align: center;
    margin-bottom: 20px;
    grid-column: 1 / -1;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    background: linear-gradient(90deg, #3b82f6, #8b5cf6);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.header p {
    font-size: 1.1rem;
    color: #cbd5e1;
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

.card {
    background: linear-gradient(145deg, #1e293b, #334155);
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
    border: 1px solid #475569;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.4);
}

.card-title {
    font-size: 1.5rem;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
    color: #e2e8f0;
}

.card-title i {
    color: #60a5fa;
}

.input-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #cbd5e1;
}

.password-container {
    position: relative;
    display: flex;
    align-items: center;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 15px;
    background-color: #1e293b;
    border: 2px solid #475569;
    border-radius: 10px;
    color: #f1f5f9;
    font-size: 1.1rem;
    transition: border-color 0.3s;
}

input[type="text"]:focus,
input[type="password"]:focus {
    outline: none;
    border-color: #60a5fa;
}

.toggle-password {
    position: absolute;
    right: 15px;
    background: none;
    border: none;
    color: #94a3b8;
    cursor: pointer;
    font-size: 1.2rem;
}

.strength-indicator {
    height: 8px;
    background-color: #475569;
    border-radius: 4px;
    margin-top: 15px;
    overflow: hidden;
}

.strength-bar {
    height: 100%;
    width: 0%;
    border-radius: 4px;
    transition: width 0.5s ease, background-color 0.5s ease;
}

.strength-text {
    margin-top: 10px;
    font-size: 0.9rem;
    text-align: right;
    font-weight: 600;
}

.criteria-list {
    list-style: none;
    margin-top: 20px;
}

.criteria-list li {
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.criteria-list i {
    width: 20px;
    text-align: center;
}

.valid {
    color: #10b981;
}

.invalid {
    color: #ef4444;
}

.generate-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 25px;
}

.option-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.option-group input[type="checkbox"],
.option-group input[type="number"] {
    width: auto;
}

.option-group label {
    margin-bottom: 0;
    font-size: 0.95rem;
}

.length-slider {
    width: 100%;
    margin: 15px 0;
}

.length-value {
    text-align: center;
    font-weight: bold;
    font-size: 1.2rem;
    color: #60a5fa;
}

.btn {
    background: linear-gradient(90deg, #3b82f6, #6366f1);
    color: white;
    border: none;
    padding: 15px 25px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    margin-top: 10px;
}

.btn:hover {
    background: linear-gradient(90deg, #2563eb, #4f46e5);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(59, 130, 246, 0.4);
}

.btn:active {
    transform: translateY(0);
}

.result-password {
    margin-top: 25px;
    background-color: #1e293b;
    padding: 15px;
    border-radius: 10px;
    border: 1px solid #475569;
    word-break: break-all;
    font-family: monospace;
    font-size: 1.2rem;
    text-align: center;
    color: #10b981;
    display: none;
}

.result-password.show {
    display: block;
}

.copy-btn {
    background-color: #475569;
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 6px;
    cursor: pointer;
    margin-top: 10px;
    transition: background-color 0.3s;
}

.copy-btn:hover {
    background-color: #64748b;
}

.footer {
    text-align: center;
    margin-top: 40px;
    color: #94a3b8;
    font-size: 0.9rem;
    grid-column: 1 / -1;
}

.tips {
    margin-top: 30px;
    background-color: rgba(30, 41, 59, 0.7);
    padding: 20px;
    border-radius: 10px;
    border-left: 4px solid #3b82f6;
}

.tips h3 {
    margin-bottom: 10px;
    color: #e2e8f0;
}

.tips ul {
    padding-left: 20px;
    color: #cbd5e1;
}

.tips li {
    margin-bottom: 8px;
}