:root {
    --primary-green: #16a34a;
    --light-green: #f0fdf4;
    --dark-green: #15803d;
    --white: #ffffff;
    --off-white: #f9fafb;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --primary-green: #22c55e;
    --light-green: #1a1a1a;
    --dark-green: #16a34a;
    --white: #111827;
    --off-white: #1f2937;
    --text-dark: #f9fafb;
    --text-light: #d1d5db;
    --border-color: #374151;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--light-green);
    color: var(--text-dark);
    line-height: 1.6;
    transition: var(--transition);
}

.login-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-green) 0%, var(--dark-green) 100%);
    padding: 20px;
}

.login-container {
    background: var(--white);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
    max-width: 400px;
    width: 100%;
    animation: fadeIn 0.5s ease;
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    font-size: 2.5rem;
    color: var(--primary-green);
    margin-bottom: 10px;
}

.login-header p {
    color: var(--text-light);
    font-size: 1rem;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.auth-form h2 {
    color: var(--text-dark);
    margin-bottom: 10px;
    font-size: 1.5rem;
}

.auth-form input {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    font-family: 'Poppins', sans-serif;
    transition: var(--transition);
    background: var(--off-white);
    color: var(--text-dark);
}

.auth-form input:focus {
    outline: none;
    border-color: var(--primary-green);
    background: var(--white);
}

.toggle-auth {
    text-align: center;
    color: var(--text-light);
    margin-top: 10px;
}

.toggle-auth a {
    color: var(--primary-green);
    text-decoration: none;
    font-weight: 500;
}

.toggle-auth a:hover {
    text-decoration: underline;
}

.auth-message {
    margin-top: 15px;
    padding: 12px;
    border-radius: 8px;
    text-align: center;
    font-size: 0.9rem;
    display: none;
}

.auth-message.success {
    background: #d1fae5;
    color: #065f46;
    display: block;
}

.auth-message.error {
    background: #fee2e2;
    color: #991b1b;
    display: block;
}

.navbar {
    background: var(--white);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-green);
}

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

.nav-links a {
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

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

.nav-actions {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.section {
    min-height: 100vh;
    padding: 4rem 2rem;
    display: flex;
    align-items: center;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.hero-section {
    text-align: center;
    background: linear-gradient(135deg, var(--light-green) 0%, var(--white) 100%);
}

.hero-title {
    font-size: 3rem;
    color: var(--text-dark);
    margin-bottom: 1rem;
    animation: slideDown 0.8s ease;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--primary-green);
    margin-bottom: 1rem;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.motivational-quote {
    background: var(--white);
    padding: 1.5rem;
    border-radius: 15px;
    border-left: 4px solid var(--primary-green);
    font-style: italic;
    color: var(--text-dark);
    margin: 2rem auto;
    max-width: 600px;
    box-shadow: var(--shadow);
}

.section-title {
    font-size: 2.5rem;
    color: var(--text-dark);
    text-align: center;
    margin-bottom: 1rem;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.input-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.input-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.input-icon {
    width: 50px;
    height: 50px;
    margin: 0 auto 1rem;
    color: var(--primary-green);
}

.input-icon svg {
    width: 100%;
    height: 100%;
}

.input-card label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
    text-align: center;
}

.input-card input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    font-family: 'Poppins', sans-serif;
    transition: var(--transition);
    background: var(--off-white);
    color: var(--text-dark);
}

.input-card input:focus {
    outline: none;
    border-color: var(--primary-green);
    background: var(--white);
}

.results-container {
    margin-top: 3rem;
    animation: fadeIn 0.5s ease;
}

.results-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow-lg);
    text-align: center;
}

.results-card h3 {
    color: var(--text-dark);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

.carbon-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-green);
    margin-bottom: 2rem;
}

.carbon-value .unit {
    font-size: 1.2rem;
    color: var(--text-light);
}

.tips-container {
    text-align: left;
    margin: 2rem 0;
    padding: 1.5rem;
    background: var(--light-green);
    border-radius: 10px;
}

.tip-item {
    padding: 0.8rem;
    margin: 0.5rem 0;
    background: var(--white);
    border-left: 4px solid var(--primary-green);
    border-radius: 5px;
    color: var(--text-dark);
}

.dashboard-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-card h4 {
    color: var(--text-light);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-green);
}

.chart-container {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow);
    margin-bottom: 3rem;
}

.history-container {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.history-container h3 {
    color: var(--text-dark);
    margin-bottom: 1.5rem;
}

.history-list {
    max-height: 400px;
    overflow-y: auto;
}

.history-item {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.history-item:last-child {
    border-bottom: none;
}

.history-date {
    color: var(--text-light);
    font-size: 0.9rem;
}

.history-value {
    font-weight: 600;
    color: var(--primary-green);
}

.btn-primary {
    background: var(--primary-green);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: 'Poppins', sans-serif;
}

.btn-primary:hover {
    background: var(--dark-green);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.1rem;
    margin-top: 1rem;
}

.btn-secondary {
    background: transparent;
    color: var(--text-dark);
    border: 2px solid var(--border-color);
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: 'Poppins', sans-serif;
}

.btn-secondary:hover {
    background: var(--off-white);
    border-color: var(--primary-green);
}

.btn-danger {
    background: #dc2626;
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: 'Poppins', sans-serif;
}

.btn-danger:hover {
    background: #b91c1c;
    transform: translateY(-2px);
}

.icon-btn {
    background: var(--off-white);
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1.2rem;
}

.icon-btn:hover {
    background: var(--light-green);
    transform: scale(1.1);
}

.footer {
    background: var(--white);
    padding: 2rem;
    text-align: center;
    color: var(--text-light);
    box-shadow: var(--shadow);
}

.footer-user {
    margin-top: 0.5rem;
    color: var(--text-light);
    font-size: 0.9rem;
}

.footer-user span {
    color: var(--primary-green);
    font-weight: 600;
}

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

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

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }

    .nav-links {
        gap: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .calculator-grid {
        grid-template-columns: 1fr;
    }

    .dashboard-stats {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 3rem 1rem;
    }
}

@media (max-width: 480px) {
    .login-container {
        padding: 30px 20px;
    }

    .hero-title {
        font-size: 1.8rem;
    }

    .carbon-value {
        font-size: 2.5rem;
    }
}

html {
    scroll-behavior: smooth;
}