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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    background-color: #FFFCF0;
    color: #000;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.newsletter-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 30px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    position: relative;
    margin-bottom: 40px;
}

.back-link {
    font-size: 14px;
    color: #000;
    text-decoration: none;
    display: inline-block;
    padding: 4px 8px;
    border-radius: 12px;
    transition: background-color 0.2s ease;
}

.back-link:hover {
    background-color: #FFF6D1;
}


.newsletter-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    text-align: center;
    padding: 0 0 60px;
}

.logo-link {
    text-decoration: none;
    color: inherit;
    cursor: pointer;
}

.logo-link:hover .logo {
    opacity: 0.7;
}

.newsletter-content .logo {
    font-size: 40px;
    margin-top: -40px;
    margin-bottom: -8px;
}

h1 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 3px;
    color: #000;
}

h1.welcome-text {
    font-size: 22px;
    font-weight: 700;
}

.subtitle {
    font-size: 16px;
    color: #000;
    margin-bottom: 35px;
}

.signup-form {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    width: 100%;
    max-width: 400px;
}

.signup-form input {
    width: 100%;
    padding: 8px 20px;
    border: none;
    border-left: 1px solid #000;
    border-right: 1px solid #000;
    border-radius: 8px;
    background: #FFFCF0;
    font-size: 15px;
    font-family: inherit;
    text-align: center;
}

.signup-form input:hover,
.signup-form input:focus {
    outline: none;
    border-color: #000;
    background: #FFF6D1;
}

.signup-form input::placeholder {
    color: #999;
}

.signup-form button {
    padding: 8px 24px;
    background: transparent;
    color: #000;
    border: none;
    border-left: 1px solid #000;
    border-right: 1px solid #000;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    font-family: inherit;
    transition: background-color 0.2s ease;
}

.signup-form button:hover:not(:disabled) {
    background-color: #FFF6D1;
}

.signup-form button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.message {
    margin-top: 20px;
    font-size: 14px;
    color: #000;
}

.disclaimer {
    text-align: center;
    font-size: 13px;
    color: #000;
    padding: 30px 0;
    margin-top: auto;
}

/* Content pages (ai-ml, sql, software-engineering-fundamentals) */
.content-page {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 30px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.page-content {
    flex: 1;
    padding: 0 0 60px;
}

.page-title {
    text-align: center;
    margin: 0 0 30px;
}

.page-title .logo {
    font-size: 40px;
    margin-top: -40px;
    margin-bottom: -8px;
}

.page-title h1 {
    font-size: 20px;
    font-weight: 400;
    margin-bottom: 0;
}

.collapsible-section {
    margin: 5px 0;
}

.section-header {
    font-size: 15px;
    font-weight: 400;
    cursor: pointer;
    padding: 4px 8px;
    transition: background-color 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border-radius: 8px;
    line-height: 1.3;
}

.section-header:hover {
    background-color: #FFF6D1;
}

.section-header::before {
    content: "⭌";
    font-size: 14px;
}

.section-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    padding-left: 20px;
}

.section-content.active {
    max-height: 1500px;
    transition: max-height 0.5s ease-in;
}

.section-content .step {
    margin: 5px 0;
}

.section-content .step-title {
    font-weight: 700;
    font-size: 15px;
    margin-bottom: 5px;
    line-height: 1.4;
}

.section-content ul {
    list-style: none;
    padding-left: 30px;
    margin: 8px 0 15px 0;
}

.section-content ul li {
    margin-bottom: 5px;
    font-size: 15px;
    position: relative;
    line-height: 1.4;
}

.section-content ul li::before {
    content: "⍤";
    position: absolute;
    left: -15px;
}

.section-content a {
    color: #000;
    text-decoration: underline;
}

.section-content a:hover {
    background-color: #FFF6D1;
}

.section-content p {
    font-size: 15px;
    line-height: 1.4;
    margin: 8px 0;
}

.intro-section .number-item {
    font-size: 15px;
    margin-bottom: 5px;
    line-height: 1.4;
}

.intro-section .number-item strong {
    font-weight: 700;
}

/* Responsive */
@media (max-width: 768px) {
    .newsletter-container {
        padding: 30px 20px;
    }

    .newsletter-content {
        padding: 40px 0;
    }

    .newsletter-content .logo {
        font-size: 35px;
    }

    h1 {
        font-size: 24px;
    }

    .subtitle {
        font-size: 14px;
    }
}