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

:root {
    --black: #000000;
    --light-green: #90EE90;
    --light-grey: #D3D3D3;
    --white: #FFFFFF;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--white);
    color: var(--black);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.main-nav {
    background-color: var(--black);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.main-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    color: var(--light-green);
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--white);
    text-decoration: none;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--light-green);
}

.btn-login, .btn-signup {
    padding: 0.5rem 1.5rem;
    border-radius: 5px;
}

.btn-login {
    border: 2px solid var(--light-green);
}

.btn-signup {
    background-color: var(--light-green);
    color: var(--black);
    font-weight: bold;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--black) 0%, #333 100%);
    color: var(--white);
    padding: 6rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--light-green);
}

.tagline {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    color: var(--light-grey);
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn {
    padding: 1rem 2rem;
    border-radius: 5px;
    text-decoration: none;
    font-weight: bold;
    transition: all 0.3s;
}

.btn-primary {
    background-color: var(--light-green);
    color: var(--black);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(144, 238, 144, 0.3);
}

.btn-secondary {
    background-color: transparent;
    color: var(--white);
    border: 2px solid var(--light-green);
}

.btn-secondary:hover {
    background-color: var(--light-green);
    color: var(--black);
}

/* Features Section */
.features {
    padding: 4rem 0;
    background-color: var(--light-grey);
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-card h3 {
    color: var(--light-green);
    margin-bottom: 1rem;
}

/* Login Page */
.login-page {
    min-height: calc(100vh - 200px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 0;
    background: linear-gradient(135deg, var(--light-grey) 0%, #f5f5f5 100%);
}

.login-container {
    background: var(--white);
    padding: 3rem;
    border-radius: 15px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.1);
    max-width: 450px;
    width: 100%;
}

.login-container h1 {
    text-align: center;
    margin-bottom: 2rem;
    color: var(--black);
    font-size: 2rem;
}

.error-message {
    background-color: #ffebee;
    color: #c62828;
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    text-align: center;
    border-left: 4px solid #c62828;
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-weight: 600;
    color: var(--black);
    font-size: 0.95rem;
}

.form-group input {
    padding: 0.9rem;
    border: 2px solid var(--light-grey);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--light-green);
    box-shadow: 0 0 0 3px rgba(144, 238, 144, 0.1);
}

.login-form .btn {
    margin-top: 1rem;
    padding: 1rem;
    font-size: 1.1rem;
    cursor: pointer;
    border: none;
}

.signup-link {
    text-align: center;
    margin-top: 1.5rem;
    color: #666;
}

.signup-link a {
    color: var(--black);
    font-weight: 600;
    text-decoration: none;
    transition: color 0.3s;
}

.signup-link a:hover {
    color: var(--light-green);
}

/* Footer */
body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

main {
    flex: 1;
}

.main-footer {
    background-color: var(--black);
    color: var(--white);
    padding: 2rem 0;
    text-align: center;
    margin-top: auto;
}

.footer-content p {
    margin: 0.5rem 0;
}

.version {
    color: var(--light-grey);
    font-size: 0.9rem;
}

.scroll-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: linear-gradient(135deg, var(--light-green) 0%, #7ed97e 100%);
    color: var(--black);
    border: none;
    border-radius: 50%;
    width: 55px;
    height: 55px;
    font-size: 1.8rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 5px 20px rgba(144, 238, 144, 0.3);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.scroll-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(144, 238, 144, 0.5);
}

.scroll-to-top.visible {
    opacity: 1;
    visibility: visible;
}