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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #0a0a0a 0%, #1a1a1a 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.container {
    position: relative;
    width: 100%;
    max-width: 450px;
    padding: 20px;
}

.login-box {
    background: #ffffff;
    border-radius: 24px;
    padding: 50px 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    position: relative;
    z-index: 10;
    animation: fadeInUp 0.6s ease-out;
}

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

.logo {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
}

.logo-circle {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #000000 0%, #333333 100%);
    border-radius: 50%;
    position: relative;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
}

.logo-circle::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 30px;
    height: 30px;
    border: 3px solid #ffffff;
    border-radius: 50%;
}

h1 {
    text-align: center;
    color: #000000;
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
}

.subtitle {
    text-align: center;
    color: #666666;
    font-size: 15px;
    margin-bottom: 35px;
}

.form-container {
    width: 100%;
}

.input-group {
    margin-bottom: 24px;
}

.input-group label {
    display: block;
    color: #000000;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 8px;
}

.input-group input {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    font-size: 15px;
    transition: all 0.3s ease;
    background: #fafafa;
    color: #000000;
}

.input-group input:focus {
    outline: none;
    border-color: #000000;
    background: #ffffff;
    box-shadow: 0 0 0 4px rgba(0, 0, 0, 0.05);
}

.password-wrapper {
    position: relative;
}

.password-wrapper input {
    padding-right: 50px;
}

.toggle-password {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    color: #666666;
    padding: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.3s ease;
}

.toggle-password:hover {
    color: #000000;
}

.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 28px;
    font-size: 14px;
}

.remember-me {
    display: flex;
    align-items: center;
    cursor: pointer;
    color: #333333;
}

.remember-me input {
    margin-right: 8px;
    cursor: pointer;
    width: 16px;
    height: 16px;
}

.remember-me span {
    user-select: none;
}

.forgot-password {
    color: #000000;
    text-decoration: none;
    font-weight: 600;
    transition: opacity 0.3s ease;
}

.forgot-password:hover {
    opacity: 0.7;
}

.submit-btn {
    width: 100%;
    padding: 16px;
    background: #000000;
    color: #ffffff;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: all 0.3s ease;
    margin-bottom: 24px;
}

.submit-btn:hover {
    background: #1a1a1a;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

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

.divider {
    text-align: center;
    margin: 30px 0;
    position: relative;
}

.divider::before,
.divider::after {
    content: '';
    position: absolute;
    top: 50%;
    width: 40%;
    height: 1px;
    background: #e0e0e0;
}

.divider::before {
    left: 0;
}

.divider::after {
    right: 0;
}

.divider span {
    background: #ffffff;
    padding: 0 16px;
    color: #999999;
    font-size: 14px;
    position: relative;
}

.social-login {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 24px;
}

.social-btn {
    padding: 12px;
    border: 2px solid #e0e0e0;
    background: #ffffff;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    color: #333333;
    transition: all 0.3s ease;
}

.social-btn:hover {
    border-color: #000000;
    background: #fafafa;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.signup-link {
    text-align: center;
    color: #666666;
    font-size: 14px;
}

.signup-link a {
    color: #000000;
    text-decoration: none;
    font-weight: 600;
    transition: opacity 0.3s ease;
}

.signup-link a:hover {
    opacity: 0.7;
}

.decorative-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

.circle {
    position: absolute;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0) 70%);
    animation: float 20s infinite ease-in-out;
}

.circle-1 {
    width: 400px;
    height: 400px;
    top: -200px;
    right: -200px;
    animation-delay: 0s;
}

.circle-2 {
    width: 300px;
    height: 300px;
    bottom: -150px;
    left: -150px;
    animation-delay: 7s;
}

.circle-3 {
    width: 250px;
    height: 250px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: 14s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    33% {
        transform: translate(50px, -50px) scale(1.1);
    }
    66% {
        transform: translate(-50px, 50px) scale(0.9);
    }
}

@media (max-width: 768px) {
    .login-box {
        padding: 40px 30px;
    }
    
    h1 {
        font-size: 24px;
    }
    
    .social-login {
        grid-template-columns: 1fr;
    }
}

img {
    height: 50px;
    width: 50px;
    border-radius: 10px;
    position: absolute; /* Hoặc 'fixed' nếu muốn nó đứng yên khi cuộn trang */
    top: 10px;    /* Cách mép trên 10px */
    left: 10px;   /* Cách mép trái 10px */
    z-index: 100;
    transition: transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275); 
    will-change: transform; 
}
img:hover {
    transform: scale(1.1);/* Phóng to 10% và hơi nghiêng cho vui mắt */
}

#particles-js {
    position: absolute;
    width: 100%;
    height: 100%;
    z-index: -10000;
}