* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f5f7fa;
    color: #171717;
}

header {
    background: white;
    padding: 22px 6%;
    border-bottom: 1px solid #e5e5e5;
}

.logo {
    font-size: 22px;
    font-weight: 800;
    text-decoration: none;
    color: #171717;
}

main {
    width: 90%;
    max-width: 900px;
    margin: auto;
}

.hero {
    padding: 80px 0;
}

.badge {
    display: inline-block;
    font-size: 12px;
    font-weight: bold;
    background: #e8ecff;
    padding: 8px 12px;
    border-radius: 20px;
}

h1 {
    font-size: 56px;
    line-height: 1.05;
    margin: 20px 0;
}

.subtitle {
    font-size: 20px;
    color: #666;
    max-width: 600px;
}

.planner {
    margin-top: 50px;
    background: white;
    padding: 35px;
    border-radius: 18px;
    box-shadow: 0 10px 40px rgba(0,0,0,.06);
}

.planning-options {
    display: flex;
    gap: 25px;
    margin: 25px 0 35px;
}

.prompt-label {
    display: block;
    font-weight: bold;
    margin-bottom: 10px;
}

textarea {
    width: 100%;
    padding: 18px;
    font-size: 16px;
    font-family: inherit;
    border: 1px solid #ddd;
    border-radius: 10px;
    resize: vertical;
}

button {
    margin-top: 20px;
    width: 100%;
    padding: 17px;
    border: 0;
    border-radius: 10px;
    font-size: 17px;
    font-weight: bold;
    cursor: pointer;
    background: #171717;
    color: white;
}

button:hover {
    opacity: .9;
}

@media (max-width: 600px) {

    h1 {
        font-size: 40px;
    }

    .planning-options {
        flex-direction: column;
    }

}


.plan-result {
    max-width: 900px;
    margin: auto;
}

.plan-actions {
    margin: 30px 0;
}

.secondary-button {
    display: inline-block;
    padding: 12px 18px;
    background: white;
    border: 1px solid #ddd;
    border-radius: 8px;
    color: #222;
    text-decoration: none;
}

.session-card {
    background: white;
    border-radius: 18px;
    padding: 30px;
    margin: 35px 0;
    box-shadow: 0 8px 30px rgba(0,0,0,.06);
}

.session-header {
    display: flex;
    justify-content: space-between;
    gap: 20px;
    align-items: flex-start;
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

.session-header h2 {
    margin: 8px 0 0;
}

.session-number {
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 1px;
    color: #666;
}

.session-duration {
    white-space: nowrap;
    font-weight: bold;
    background: #f4f4f4;
    padding: 10px 14px;
    border-radius: 20px;
}

.session-objectives {
    margin: 25px 0;
}

.activity-card {
    border: 1px solid #e7e7e7;
    border-radius: 14px;
    padding: 24px;
    margin: 20px 0;
}

.activity-top {
    display: flex;
    justify-content: space-between;
    gap: 20px;
}

.activity-top h3 {
    margin: 8px 0;
    font-size: 22px;
}

.activity-source {
    font-size: 11px;
    font-weight: 800;
    letter-spacing: .5px;
}

.activity-source.ai {
    opacity: .65;
}

.activity-duration {
    white-space: nowrap;
    font-weight: bold;
}

.activity-objective {
    color: #555;
}

.activity-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin: 20px 0;
}

.activity-explanation {
    margin: 20px 0;
}

details {
    margin-top: 12px;
    padding: 12px 0;
    border-top: 1px solid #eee;
}

summary {
    cursor: pointer;
    font-weight: bold;
}

.session-notes {
    background: #f7f7f7;
    border-radius: 10px;
    padding: 18px;
    margin-top: 25px;
}

.original-request {
    margin: 50px 0;
    padding: 25px;
    border: 1px solid #ddd;
    border-radius: 12px;
}

@media (max-width: 600px) {

    .session-header,
    .activity-top {
        flex-direction: column;
    }

    .activity-info {
        grid-template-columns: 1fr;
    }
}