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

body {
    font-family: 'Segoe UI', 'Hiragino Sans', 'Yu Gothic', sans-serif;
    line-height: 1.8;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa 0%, #e8f0f8 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background: #fff;
    padding: 1.5rem 2rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 1rem;
    position: relative;
}

.logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: #2c5aa0;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.patent-badge {
    font-size: 0.65rem;
    background: #e3f2fd;
    color: #2c5aa0;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-weight: 600;
}

.hamburger-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.3rem;
}

.patent-notice {
    font-size: 0.65rem;
    font-weight: 600;
    color: #1565c0;
    background: #b3d9ff;
    padding: 0.3rem 0.6rem;
    border-radius: 4px;
    text-align: center;
    line-height: 1.3;
    white-space: nowrap;
    margin-left: -1rem;
}

.hamburger-menu {
    width: 40px;
    height: 40px;
    background: white;
    border: 2px solid #2c5aa0;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    padding: 8px;
    transition: all 0.3s;
    position: relative;
    z-index: 1001;
    margin-left: -0.45cm;
}

.hamburger-menu:hover {
    background: #f0f4f8;
}

.hamburger-menu span {
    display: block;
    width: 20px;
    height: 2px;
    background: #2c5aa0;
    transition: all 0.3s;
}

.hamburger-menu.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger-menu.active span:nth-child(2) {
    opacity: 0;
}

.hamburger-menu.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

.dropdown-menu {
    position: absolute;
    top: 50px;
    left: 0;
    background: white;
    border: 2px solid #2c5aa0;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    display: none;
    flex-direction: column;
    min-width: 180px;
    overflow: hidden;
    z-index: 1000;
}

.dropdown-menu.active {
    display: flex;
}

.dropdown-menu a {
    padding: 1rem 1.5rem;
    color: #2c5aa0;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
    border-bottom: 1px solid #e3f2fd;
}

.dropdown-menu a:last-child {
    border-bottom: none;
}

.dropdown-menu a:hover {
    background: #f0f4f8;
    padding-left: 2rem;
}

.nav-buttons button {
    margin-left: 1rem;
    padding: 0.6rem 1.5rem;
    border: none;
    border-radius: 6px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-signup {
    background: #2c5aa0;
    color: white;
}

.btn-signup:hover {
    background: #234a85;
}

.login-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 1rem 2rem;
    padding-top: 1.5rem;
}

.login-card {
    background: white;
    border-radius: 16px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.1);
    max-width: 450px;
    width: 100%;
    padding: 3rem;
}

.login-header {
    text-align: center;
    margin-bottom: 2rem;
}

.login-header h1 {
    font-size: 2rem;
    color: #1a1a1a;
    margin-bottom: 0;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: #333;
    font-weight: 600;
    font-size: 0.95rem;
}

.form-group input {
    width: 100%;
    padding: 0.9rem 1rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s;
    font-family: 'Segoe UI', 'Hiragino Sans', 'Yu Gothic', sans-serif;
}

.form-group input:focus {
    outline: none;
    border-color: #2c5aa0;
    box-shadow: 0 0 0 3px rgba(44, 90, 160, 0.1);
}

.form-group input::placeholder {
    color: #aaa;
}

.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.remember-me {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.remember-me input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.remember-me label {
    font-size: 0.9rem;
    color: #666;
    cursor: pointer;
}

.forgot-password {
    font-size: 0.9rem;
    color: #2c5aa0;
    text-decoration: none;
}

.forgot-password:hover {
    text-decoration: underline;
}

.btn-login {
    width: 100%;
    padding: 1rem;
    background: #2c5aa0;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-login:hover:not(:disabled) {
    background: #234a85;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(44, 90, 160, 0.3);
}

.btn-login:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
}

.error-message {
    color: #d32f2f;
    font-size: 0.85rem;
    margin-top: 0.5rem;
    display: none;
    padding: 0.75rem;
    background: #ffebee;
    border-radius: 6px;
    border-left: 3px solid #d32f2f;
}

.error-message.show {
    display: block;
}

.divider {
    text-align: center;
    margin: 2rem 0;
    position: relative;
}

.divider::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 1px;
    background: #e0e0e0;
}

.divider span {
    background: white;
    padding: 0 1rem;
    position: relative;
    color: #666;
    font-size: 0.9rem;
}

.register-link {
    text-align: center;
    margin-top: 1.5rem;
    font-size: 0.95rem;
    color: #666;
}

.register-link a {
    color: #2c5aa0;
    text-decoration: none;
    font-weight: 600;
}

.register-link a:hover {
    text-decoration: underline;
}

.social-login {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.btn-social {
    width: 100%;
    padding: 0.9rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    background: white;
}

.btn-social:hover {
    border-color: #2c5aa0;
    background: #f8f9fa;
}

.btn-google {
    color: #333;
}

.btn-twitter {
    color: #333;
}

footer {
    background: #1a1a1a;
    color: white;
    padding: 2rem;
    text-align: center;
    margin-top: auto;
}

footer p {
    opacity: 0.8;
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .login-card {
        padding: 2rem 1.5rem;
    }

    .login-header h1 {
        font-size: 1.6rem;
    }

    .form-options {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .nav-buttons button {
        padding: 0.5rem 1rem;
        font-size: 0.85rem;
    }
}