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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background-color: #ffffff;
    color: #2d3748;
    overflow-x: hidden;
    position: relative;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Dark Mode */
body.dark-mode {
    background-color: #1a1a1a;
    color: #e5e7eb;
}

/* Video Background */
.video-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.video-background video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.video-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(255, 255, 255, 0.92) 100%);
    transition: background 0.3s ease;
}

body.dark-mode .video-overlay {
    background: linear-gradient(135deg, rgba(26, 26, 26, 0.95) 0%, rgba(26, 26, 26, 0.92) 100%);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    padding: 1rem 2rem;
    z-index: 1000;
    transition: background 0.3s ease, border-color 0.3s ease;
}

body.dark-mode .navbar {
    background: rgba(26, 26, 26, 0.9);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: #10a37f;
}

.logo-text {
    background: linear-gradient(135deg, #10a37f 0%, #0d8c6d 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: #6b7280;
    font-weight: 500;
    transition: color 0.3s ease;
    cursor: not-allowed;
    opacity: 0.6;
}

.nav-link.disabled:hover {
    color: #6b7280;
}

.btn-signup {
    background: #10a37f;
    color: white;
    padding: 0.625rem 1.25rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: not-allowed;
    opacity: 0.6;
}

/* Theme Toggle Button */
.theme-toggle {
    background: transparent;
    border: 2px solid #e5e7eb;
    border-radius: 0.5rem;
    padding: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    color: #6b7280;
}

.theme-toggle:hover {
    background: rgba(16, 163, 127, 0.1);
    border-color: #10a37f;
    color: #10a37f;
}

body.dark-mode .theme-toggle {
    border-color: #4b5563;
    color: #e5e7eb;
}

body.dark-mode .theme-toggle:hover {
    background: rgba(16, 163, 127, 0.2);
    border-color: #10a37f;
    color: #10a37f;
}

.sun-icon {
    display: block;
}

.moon-icon {
    display: none;
}

body.dark-mode .sun-icon {
    display: none;
}

body.dark-mode .moon-icon {
    display: block;
}

/* Main Content */
.main-content {
    padding-top: 120px;
    min-height: calc(100vh - 60px);
    display: flex;
    align-items: center;
    justify-content: center;
}

.content-container {
    max-width: 800px;
    width: 100%;
    padding: 2rem;
    text-align: center;
}

.main-heading {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #10a37f 0%, #0d8c6d 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.tagline {
    font-size: 1.5rem;
    color: #6b7280;
    margin-bottom: 3rem;
    font-weight: 400;
}

/* Chat Container */
.chat-container {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 1.5rem;
    padding: 2.5rem;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.08);
    margin-bottom: 3rem;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

body.dark-mode .chat-container {
    background: rgba(31, 31, 31, 0.95);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.input-label {
    display: block;
    font-size: 1.125rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 1.5rem;
    text-align: left;
    transition: color 0.3s ease;
}

body.dark-mode .input-label {
    color: #e5e7eb;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.tax-input {
    width: 100%;
    padding: 1rem 1.25rem;
    font-size: 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 0.75rem;
    outline: none;
    transition: all 0.3s ease;
    background: white;
    color: #2d3748;
}

body.dark-mode .tax-input {
    background: #2d2d2d;
    border-color: #4b5563;
    color: #e5e7eb;
}

body.dark-mode .tax-input::placeholder {
    color: #6b7280;
}

.tax-input:focus {
    border-color: #10a37f;
    box-shadow: 0 0 0 3px rgba(16, 163, 127, 0.1);
}

.tax-input::placeholder {
    color: #9ca3af;
}

.send-button {
    background: #10a37f;
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 50px;
}

.send-button:hover {
    background: #0d8c6d;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 163, 127, 0.3);
}

.send-button:active {
    transform: translateY(0);
}

/* Coming Soon Message */
.coming-soon-message {
    display: none;
    margin-top: 2rem;
    padding: 2rem;
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    border-radius: 1rem;
    border: 2px solid #fbbf24;
    animation: slideIn 0.5s ease-out;
}

.coming-soon-message.show {
    display: block;
}

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

.message-content {
    text-align: center;
}

.construction-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.message-content h3 {
    font-size: 1.5rem;
    color: #92400e;
    margin-bottom: 0.75rem;
}

.message-content p {
    color: #78350f;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.notify-text {
    font-weight: 600;
    color: #92400e;
}

/* Features Preview */
.features-preview {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.5rem;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 0.75rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    font-weight: 500;
    color: #4b5563;
    transition: all 0.3s ease;
}

body.dark-mode .feature-item {
    background: rgba(31, 31, 31, 0.9);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    color: #e5e7eb;
}

.feature-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 1.5rem;
}

/* Footer */
.footer {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    padding: 1.5rem 2rem;
    text-align: center;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    color: #6b7280;
    font-size: 0.875rem;
    transition: all 0.3s ease;
}

body.dark-mode .footer {
    background: rgba(26, 26, 26, 0.9);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #9ca3af;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        gap: 1rem;
        font-size: 0.875rem;
    }

    .main-heading {
        font-size: 2.5rem;
    }

    .tagline {
        font-size: 1.125rem;
    }

    .chat-container {
        padding: 1.5rem;
    }

    .features-preview {
        flex-direction: column;
        align-items: center;
    }

    .feature-item {
        width: 100%;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    .navbar {
        padding: 1rem;
    }

    .nav-links {
        gap: 0.5rem;
    }

    .nav-links li:not(:last-child) {
        display: none;
    }

    .nav-links li:last-child {
        display: block;
    }

    .logo {
        font-size: 1.25rem;
    }

    .main-heading {
        font-size: 2rem;
    }

    .tagline {
        font-size: 1rem;
    }
}