:root {
    --tomato: hsl(4, 100%, 67%); /* Original #FF6155 */
    --dark-slate-grey: hsl(234, 29%, 20%); /* Original #242742 */
    --charcoal-grey: hsl(235, 18%, 26%); /* Original #36384D */
    --grey: hsl(231, 7%, 60%);
    --white: hsl(0, 0%, 100%);
    --error-bg: hsla(4, 100%, 67%, 0.15); /* Light red for error background */
}

body {
    margin: 0;
    font-family: 'Roboto', sans-serif;
    background-color: var(--charcoal-grey); /* Dark background for the page */
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    box-sizing: border-box;
}

.container {
    width: 100%;
    max-width: 930px; /* Max width for the newsletter card */
}

.newsletter-card {
    background-color: var(--white);
    border-radius: 24px; /* More pronounced rounded corners */
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
    display: flex;
    overflow: hidden; /* Ensures illustration doesn't break border radius */
    padding: 20px; /* Padding inside the card before content/illustration */
}

.content {
    flex: 1.5; /* Give more space to content */
    padding: 40px; /* Padding around the text content */
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.content h1 {
    font-size: 3.5rem; /* 56px */
    color: var(--dark-slate-grey);
    margin-top: 0;
    margin-bottom: 20px;
}

.content p {
    font-size: 1rem; /* 16px */
    line-height: 1.6;
    color: var(--dark-slate-grey);
    margin-bottom: 25px;
}

.content ul {
    list-style: none;
    padding-left: 0;
    margin-bottom: 30px;
}

.content ul li {
    font-size: 1rem;
    color: var(--dark-slate-grey);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
}

.content ul li svg {
    margin-right: 15px;
    flex-shrink: 0; /* Prevent SVG from shrinking */
}

.form-group {
    margin-bottom: 20px;
}

.label-line {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 8px;
}

.form-group label {
    font-size: 0.75rem; /* 12px */
    font-weight: 700;
    color: var(--dark-slate-grey);
}

.error-message {
    font-size: 0.75rem; /* 12px */
    font-weight: 700;
    color: var(--tomato);
    display: none; /* Hidden by default */
}

.form-group input[type="text"] {
    width: 100%;
    padding: 15px 20px;
    border: 1px solid var(--grey);
    border-radius: 8px;
    font-size: 1rem;
    box-sizing: border-box;
    color: var(--dark-slate-grey);
}
.form-group input[type="text"]::placeholder {
    color: var(--grey);
}

.form-group input[type="text"].error {
    border-color: var(--tomato);
    background-color: var(--error-bg);
    color: var(--tomato);
}
.form-group input[type="text"].error::placeholder {
    color: hsla(4, 100%, 67%, 0.5);
}


button[type="submit"],
.success-message button {
    width: 100%;
    background-color: var(--dark-slate-grey);
    color: var(--white);
    border: none;
    padding: 18px 20px;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

button[type="submit"]:hover,
.success-message button:hover {
    background: linear-gradient(to right, #FF527B, #FF6A3A); /* Gradient from design */
    box-shadow: 0 10px 20px rgba(255, 97, 85, 0.3);
}

.illustration {
    flex: 1;
    background-image: linear-gradient(150deg, #FF6A3A, #FF527B); /* Simplified gradient */
    /* In a real project, this would be:
    background-image: url('path/to/your/illustration.svg');
    background-size: cover;
    background-position: center; */
    border-radius: 12px; /* Rounded corners for the illustration itself */
    margin: -20px -20px -20px 0; /* Negative margin to fill up to the card's edge on right/top/bottom */
    position: relative; /* For potential pseudo-elements if complex shapes were drawn */
}

/* Success Message Styling */
.success-message {
    background-color: var(--white);
    padding: 50px 60px;
    border-radius: 24px;
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
    max-width: 500px;
    width: 100%;
    box-sizing: border-box;
}

.success-message svg {
    margin-bottom: 30px;
}

.success-message h2 {
    font-size: 3.5rem; /* 56px */
    color: var(--dark-slate-grey);
    margin-top: 0;
    margin-bottom: 25px;
    line-height: 1.1;
}

.success-message p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--dark-slate-grey);
    margin-bottom: 30px;
}

.success-message p strong {
    color: var(--dark-slate-grey);
    font-weight: 700;
}

/* Mobile Styles */
@media (max-width: 768px) {
    body {
        align-items: flex-start; /* Align card to top on mobile */
        background-color: var(--white); /* Mobile design has white BG behind card */
        padding: 0;
    }

    .container {
        max-width: 100%;
    }

    .newsletter-card {
        flex-direction: column-reverse; /* Image first, then content */
        border-radius: 0;
        box-shadow: none;
        padding: 0; /* No padding for the card itself, handled by content/illustration */
        min-height: 100vh; /* Ensure it can fill screen if content is short */
    }

    .illustration {
        flex: none; /* Reset flex behavior */
        height: 280px; /* Fixed height for mobile illustration */
        width: 100%;
        background-size: cover;
        background-position: center bottom; /* Adjust if using a real image */
        border-radius: 0 0 20px 20px; /* Only bottom corners rounded */
        margin: 0; /* Reset negative margins */
    }

    .content {
        padding: 30px 25px; /* Adjust padding for mobile */
        flex: 1; /* Allow content to grow and push form to bottom */
    }

    .content h1 {
        font-size: 2.5rem; /* 40px */
    }

    .form-group input[type="text"],
    button[type="submit"] {
        padding: 16px 20px;
    }

    .success-message {
        max-width: 100%;
        min-height: 100vh; /* Make success message full screen on mobile */
        border-radius: 0;
        box-shadow: none;
        padding: 15% 25px 40px 25px; /* More padding at top, less at bottom */
        display: flex;
        flex-direction: column;
        justify-content: space-between; /* Pushes button to bottom */
    }

    .success-message h2 {
        font-size: 2.5rem; /* 40px */
        margin-top: 80px; /* Push title down from icon */
    }
    .success-message p {
        flex-grow: 1; /* Allows paragraph to take available space */
        margin-bottom: 0;
    }
    .success-message button {
         margin-top: auto; /* Pushes button to the very bottom */
    }
}