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

body {
    background: linear-gradient(145deg, #eef2f6 0%, #dde5ed 100%);
    padding: 20px 12px 40px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    font-family: 'Segoe UI', 'Nirmala UI', 'Vrinda', 'Noto Sans Bengali', 'Hind Siliguri', 'Siyam Rupali', Arial, sans-serif;
}

.landing-container {
    max-width: 520px;
    width: 100%;
    margin: 0 auto;
    background: #ffffff;
    border-radius: 40px 40px 30px 30px;
    box-shadow: 0 25px 45px rgba(0, 25, 45, 0.3);
    overflow: hidden;
    border: 1px solid rgba(255,255,255,0.7);
}

.header-grad {
    background: linear-gradient(135deg, #0a2c4a, #124067, #1b5380);
    padding: 24px 20px 20px;
    color: white;
    text-align: center;
    border-bottom: 5px solid #ffaa33;
}

.header-grad h1 {
    font-size: 2.4rem;
    font-weight: 800;
    letter-spacing: 1px;
    text-shadow: 4px 4px 0 #082032;
    line-height: 1.2;
}

.header-grad .sub-title {
    font-size: 1.3rem;
    background: rgba(0,0,0,0.25);
    display: inline-block;
    padding: 8px 28px;
    border-radius: 60px;
    margin-top: 10px;
    border: 1px solid #ffcc80;
    font-weight: 500;
}

.header-grad .author-name {
    font-size: 1.1rem;
    margin-top: 8px;
    opacity: 0.9;
}

.book-showcase {
    padding: 25px 18px 15px;
    background: #f5faff;
    display: flex;
    flex-direction: column;
    align-items: center;
    border-bottom: 2px dashed #9bb7d4;
}

.cover-img {
    width: 75%;
    max-width: 280px;
    border-radius: 24px;
    box-shadow: 0 22px 30px -12px #022b4f;
    border: 4px solid white;
    outline: 1px solid #b8d0e5;
    background: #ffffff;
    display: block;
}

.price-tag {
    margin-top: 15px;
    font-size: 1.8rem;
    font-weight: 800;
    background: #e04e20;
    color: white;
    padding: 8px 30px;
    border-radius: 60px;
    display: inline-flex;
    align-items: center;
    gap: 12px;
    box-shadow: 0 8px 0 #832d0e;
}

.price-tag small {
    font-size: 1.2rem;
    font-weight: 400;
    text-decoration: line-through;
    opacity: 0.8;
}

.offer-badge {
    background: #1e7323;
    color: white;
    padding: 5px 16px;
    border-radius: 60px;
    font-weight: 700;
    font-size: 1rem;
}

.author-info {
    background: #ecf3fc;
    padding: 14px 18px;
    margin: 15px 18px 10px;
    border-radius: 50px;
    font-size: 1.15rem;
    border-left: 8px solid #1d4e7a;
    font-weight: 500;
    box-shadow: inset 0 1px 5px #bdd1e6;
}

.author-info i {
    color: #c5451e;
    margin-right: 10px;
}

.section-wrap {
    padding: 5px 20px 10px;
}

.section-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: #09304a;
    border-bottom: 4px solid #fcb26b;
    padding-bottom: 6px;
    margin: 20px 0 15px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.bullet-list {
    list-style: none;
}

.bullet-list li {
    font-size: 1.1rem;
    margin-bottom: 14px;
    display: flex;
    align-items: flex-start;
    gap: 14px;
    background: #f1f8ff;
    padding: 12px 18px;
    border-radius: 50px;
    border: 1px solid #c7dbef;
    box-shadow: 0 3px 6px #c3d6ea;
}

.bullet-list li i {
    color: #1f6e5a;
    font-size: 1.5rem;
    min-width: 30px;
}

.topic-table {
    background: white;
    border-radius: 32px;
    padding: 18px 12px;
    margin: 10px 16px 20px;
    box-shadow: 0 12px 22px #b1cbe2;
}

.topic-header {
    display: flex;
    align-items: center;
    gap: 10px;
    background: #deecfa;
    padding: 12px 20px;
    border-radius: 60px;
    margin-bottom: 16px;
}

.topic-header i {
    font-size: 2rem;
    color: #143857;
}

.topic-header span {
    font-weight: 800;
    font-size: 1.4rem;
}

.topic-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 6px;
    border-bottom: 1px solid #cbdef2;
    font-size: 1.05rem;
}

.topic-left {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.topic-no {
    background: #153e60;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    flex-shrink: 0;
}

.topic-name {
    font-weight: 600;
    color: #00263b;
}

.topic-page {
    background: #e2ecf5;
    padding: 5px 16px;
    border-radius: 40px;
    font-weight: 600;
    color: #0f3c57;
}

.price-row {
    background: #fbebd2;
    margin: 15px 18px;
    border-radius: 60px;
    padding: 12px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px;
}

.price-label {
    font-weight: 700;
}

.old-price {
    text-decoration: line-through;
    color: #5f5f5f;
    font-size: 1.2rem;
}

.new-price {
    background: #c62828;
    color: white;
    padding: 8px 30px;
    border-radius: 60px;
    font-weight: 800;
    font-size: 1.7rem;
}

.fb-badge {
    background: #1877f2;
    color: white;
    padding: 16px 15px;
    border-radius: 30px;
    text-align: center;
    font-size: 1.4rem;
    font-weight: 700;
    margin: 10px 18px 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    border: 2px solid white;
}

.success-message {
    background: #28a745;
    color: white;
    padding: 15px;
    border-radius: 10px;
    margin: 10px 16px;
    text-align: center;
    display: none;
}

.error-message {
    background: #dc3545;
    color: white;
    padding: 15px;
    border-radius: 10px;
    margin: 10px 16px;
    text-align: center;
    display: none;
}

.order-panel {
    background: #102b42;
    padding: 30px 18px 25px;
    border-radius: 48px 48px 0 0;
    color: white;
    margin-top: 25px;
}

.order-panel h3 {
    font-size: 2rem;
    text-align: center;
    color: #ffd966;
    margin-bottom: 20px;
}

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

.input-group label {
    display: block;
    color: #c2dcf5;
    font-weight: 500;
    margin-bottom: 5px;
    font-size: 1.1rem;
}

.input-group input,
.input-group textarea {
    width: 100%;
    padding: 16px 20px;
    border-radius: 60px;
    border: none;
    background: #f0f9ff;
    font-size: 1.1rem;
    font-family: inherit;
    border: 2px solid transparent;
}

.input-group input:focus,
.input-group textarea:focus {
    outline: none;
    border-color: #fdad3a;
    background: white;
}

.summary-box {
    background: #193f5c;
    padding: 16px 22px;
    border-radius: 40px;
    margin: 18px 0;
    font-size: 1.2rem;
}

.summary-row {
    display: flex;
    justify-content: space-between;
    padding: 8px 0;
    border-bottom: 1px solid #6187a5;
}

.total {
    font-size: 1.6rem;
    color: #ffe48f;
    border-bottom: none;
    font-weight: 800;
}

.order-btn {
    background: #f05a28;
    width: 100%;
    border: none;
    color: white;
    font-size: 1.9rem;
    font-weight: 800;
    padding: 16px 10px;
    border-radius: 60px;
    box-shadow: 0 9px 0 #902d0e;
    cursor: pointer;
    border: 2px solid #ffb94b;
    font-family: inherit;
    transition: 0.05s linear;
}

.order-btn:active {
    transform: translateY(7px);
    box-shadow: 0 2px 0 #902d0e;
}

.hotline {
    background: #1a5470;
    padding: 18px;
    border-radius: 50px;
    margin: 20px 0 10px;
    font-size: 1.6rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    border: 1px solid #f9b83a;
}

.footer {
    text-align: center;
    padding: 16px;
    color: #2d2d2d;
    background: #eaf1f9;
}

.footer small {
    font-size: 0.9rem;
    opacity: 0.7;
}

@media (max-width: 400px) {
    .header-grad h1 {
        font-size: 2rem;
    }
    .price-tag {
        font-size: 1.5rem;
        padding: 8px 20px;
    }
    .topic-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 5px;
    }
}