/* --- CSS Variables and Base Styles --- */
:root {
    --dark-bg: #0d1117;
    --card-bg: #1a1f26;
    --accent-green: #10b981; /* Bright Green */
    --light-text: #e5e7eb;
    --gray-text: #9ca3af; /* Equivalent to gray-400/500 */
    --border-color-dark: #374151; /* Equivalent to gray-700/600 for borders */
    --red-error: #dc2626; /* Equivalent to red-600 */
    --green-hover: #10b981; /* Default accent green */
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--dark-bg);
    /* Gradient for dark tech/green look */
    background-image: radial-gradient(at 0% 0%, #1e3a8a 0%, transparent 50%),
                      radial-gradient(at 100% 100%, #064e3b 0%, transparent 50%);
    background-size: 100% 100%;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 1rem; /* p-4 */
    color: var(--light-text);
}

/* --- Message Box Styles --- */
#message-container {
    position: fixed;
    top: 1.5rem; /* top-6 */
    right: 1.5rem; /* right-6 */
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s ease; /* duration-500 */
    z-index: 50;
}

#message-box {
    padding: 1rem; /* p-4 */
    border-radius: 0.75rem; /* rounded-xl */
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05); /* shadow-lg */
    font-weight: 600; /* font-semibold */
}

/* Message Box Types */
.msg-success {
    background-color: var(--accent-green);
    color: var(--dark-bg);
}

.msg-error {
    background-color: var(--red-error);
    color: white;
}

/* --- Main Card Styles --- */
.main-card {
    width: 100%;
    max-width: 32rem; /* max-w-lg */
    padding: 3rem; /* md:p-12 */
    background-color: var(--card-bg);
    border: 1px solid var(--border-color-dark); /* border border-gray-700 */
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25); /* shadow-2xl */
    border-radius: 1rem; /* rounded-2xl */
    text-align: center;
}
@media (max-width: 768px) {
    .main-card {
        padding: 2rem; /* p-8 */
    }
}

/* --- Typography and Branding --- */
.logo-title {
    font-size: 3.75rem; /* text-6xl */
    font-weight: 900; /* font-extrabold */
    margin-bottom: 1rem; /* mb-4 */
    letter-spacing: -0.05em; /* tracking-tighter */
    color: var(--light-text);
}
.logo-title span {
    color: var(--accent-green);
}

.logo-subtitle {
    font-size: 1.25rem; /* text-xl */
    font-weight: 300; /* font-light */
    margin-bottom: 3rem; /* mb-12 */
    color: var(--gray-text);
    border-bottom: 1px solid var(--border-color-dark);
    padding-bottom: 1.5rem; /* pb-6 */
}

/* Main Headline */
.headline-section {
    margin-bottom: 3rem; /* mb-12 */
}
.headline-title {
    font-size: 3rem; /* text-5xl (default) */
    font-weight: 900; /* font-black */
    margin-bottom: 1rem; /* mb-4 */
    color: white;
}
@media (min-width: 768px) {
    .headline-title {
        font-size: 3.75rem; /* md:text-6xl */
    }
}
.headline-text {
    font-size: 1.125rem; /* text-lg */
    color: #d1d5db; /* gray-300 */
}

/* --- Form Styles --- */
.subscription-form {
    display: flex;
    flex-direction: column;
    gap: 1rem; /* space-y-4 */
}

.email-input {
    width: 100%;
    padding: 0.75rem 1.25rem; /* py-3 px-5 */
    font-size: 1.125rem; /* text-lg */
    color: white;
    background-color: var(--dark-bg);
    border: 1px solid #4b5563; /* border border-gray-600 */
    border-radius: 0.75rem; /* rounded-xl */
    transition: all 0.3s ease; /* transition duration-300 */
}
.email-input::placeholder {
    color: #6b7280; /* placeholder-gray-500 */
}
.email-input:focus {
    outline: none;
    border-color: var(--accent-green);
    box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.5); /* focus:ring-2 focus:ring-accent-green */
}

.submit-button {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem; /* space-x-2 */
    padding: 0.75rem 1.25rem; /* py-3 px-5 */
    font-size: 1.25rem; /* text-xl */
    font-weight: 700; /* font-bold */
    border-radius: 0.75rem; /* rounded-xl */
    color: var(--dark-bg);
    background-color: var(--accent-green);
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    box-shadow: 0 10px 15px -3px rgba(16, 185, 129, 0.25); /* shadow-lg shadow-green-700/50 */
}
.submit-button:hover {
    background-color: #059669; /* Slightly darker green (hover:bg-green-500) */
}
.submit-button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Spin Animation for Loading Indicator */
@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}
.animate-spin {
    animation: spin 1s linear infinite;
}
.hidden {
    display: none;
}

/* --- Footer Styles --- */
.footer {
    margin-top: 2rem; /* mt-8 */
    text-align: center;
    color: #9ca3af; /* text-gray-500 */
    font-size: 0.875rem; /* text-sm */
}
.footer-links {
    margin-top: 0.5rem; /* mt-2 */
}
.footer-links a {
    margin-right: 1rem;
    margin-left: 1rem;
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.2s ease;
}
.footer-links a:hover {
    color: var(--accent-green);
}
.separator {
    color: #4b5563; /* text-gray-600 */
}