:root {
    --bg: #f3f9ff;
    --surface: #ffffff;
    --surface-soft: #f7fbff;
    --surface-alt: #eef6ff;
    --text: #16324f;
    --muted: #55718f;
    --primary: #0077cc;
    --primary-dark: #045a99;
    --secondary: #00b894;
    --accent: #ffb703;
    --line: #d6e7f5;
    --danger: #b42318;
    --success: #027a48;
    --radius: 14px;
    --radius-lg: 18px;
    --shadow: 0 10px 30px rgba(22, 50, 79, 0.08);
    --shadow-soft: 0 14px 32px rgba(14, 43, 68, 0.1);
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", "Nunito Sans", Tahoma, sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at 12% 8%, rgba(115, 186, 255, 0.14), transparent 28%),
        radial-gradient(circle at 88% 0%, rgba(0, 184, 148, 0.12), transparent 25%),
        linear-gradient(180deg, #f8fcff 0%, #f2f8ff 55%, #edf6ff 100%);
    line-height: 1.55;
}

img {
    max-width: 100%;
    display: block;
}

a {
    color: var(--primary);
}

.container {
    width: min(1120px, 92%);
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 6px 18px rgba(18, 53, 84, 0.05);
    z-index: 20;
}

.nav-wrap {
    display: flex;
    justify-content: space-between;
    align-items: center;
    min-height: 74px;
    gap: 1rem;
}

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
    gap: 0.6rem;
}

.logo-image {
    width: min(560px, 72vw);
    max-height: 76px;
    object-fit: contain;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.main-nav a {
    text-decoration: none;
    color: var(--text);
    padding: 0.5rem 0.7rem;
    border-radius: 8px;
    transition: background 0.2s ease, color 0.2s ease;
}

.main-nav a:hover {
    background: #edf6ff;
    color: #0d4f86;
}

.main-nav a.is-active {
    background: #e7f3ff;
    color: #025ea4;
    font-weight: 600;
}

.menu-toggle {
    display: none;
    border: 1px solid #b8d6ef;
    background: white;
    border-radius: 8px;
    padding: 0.5rem 0.75rem;
}

.section {
    padding: clamp(2.6rem, 5vw, 4.2rem) 0;
}

.section-alt {
    background: var(--surface-alt);
}

.top-slider {
    padding: 0;
    position: relative;
}

.slider {
    position: relative;
    width: 100%;
    border-radius: 0;
    overflow: hidden;
    box-shadow: var(--shadow-soft);
}

.slider-track {
    position: relative;
    min-height: clamp(180px, 34vw, 460px);
}

.slide {
    position: absolute;
    inset: 0;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.45s ease, visibility 0.45s ease;
    padding: clamp(1rem, 2.6vw, 2.2rem) 0;
    overflow: hidden;
}

.slide.is-active {
    opacity: 1;
    visibility: visible;
}

.slide-inner {
    width: min(1200px, 94%);
    margin: 0 auto;
    height: 100%;
    display: grid;
    grid-template-columns: 1fr;
    align-items: center;
    gap: clamp(1rem, 2vw, 2rem);
    position: relative;
    z-index: 2;
}

.slide-copy {
    color: #fff;
    max-width: 760px;
    background: rgba(6, 26, 46, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(5px);
    border-radius: 14px;
    padding: clamp(0.9rem, 2vw, 1.35rem);
}

.slide-eyebrow {
    margin: 0 0 0.6rem;
    display: inline-block;
    border: 1px solid rgba(255, 255, 255, 0.5);
    background: rgba(255, 255, 255, 0.2);
    border-radius: 999px;
    font-size: 0.84rem;
    font-weight: 700;
    padding: 0.28rem 0.75rem;
}

.slide-copy h2 {
    margin: 0 0 0.7rem;
    line-height: 1.2;
    font-size: clamp(1.45rem, 3.3vw, 2.8rem);
    max-width: 680px;
}

.slide-copy p {
    margin: 0 0 1rem;
    font-size: clamp(0.95rem, 1.35vw, 1.12rem);
    color: #eef8ff;
    max-width: 620px;
}

.slide-bg {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    z-index: 0;
}

.slide::after {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(8, 29, 49, 0.58) 0%, rgba(8, 29, 49, 0.34) 42%, rgba(8, 29, 49, 0.26) 100%);
    z-index: 1;
}

.slider-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 42px;
    height: 42px;
    border-radius: 50%;
    border: 1px solid rgba(255, 255, 255, 0.6);
    background: rgba(4, 21, 38, 0.34);
    color: #fff;
    font-size: 1.2rem;
    cursor: pointer;
    z-index: 2;
    transition: background 0.2s ease, transform 0.2s ease;
}

.slider-nav:hover {
    background: rgba(4, 21, 38, 0.52);
    transform: translateY(-50%) scale(1.04);
}

.slider-nav.prev {
    left: 1rem;
}

.slider-nav.next {
    right: 1rem;
}

.slider-dots {
    position: absolute;
    left: 50%;
    bottom: 1rem;
    transform: translateX(-50%);
    display: flex;
    gap: 0.45rem;
    z-index: 2;
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    border: 0;
    background: rgba(255, 255, 255, 0.55);
    cursor: pointer;
}

.dot.is-active {
    background: #fff;
}

.hero {
    padding: clamp(2.7rem, 5vw, 4.4rem) 0 clamp(2.5rem, 4vw, 4rem);
    position: relative;
}

.hero::after {
    content: "";
    position: absolute;
    right: 0;
    bottom: 0;
    width: min(340px, 40vw);
    height: min(240px, 28vw);
    background: radial-gradient(circle at center, rgba(0, 184, 148, 0.2), transparent 70%);
    pointer-events: none;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 1fr;
    gap: 2rem;
    align-items: center;
}

.kicker {
    display: inline-block;
    background: #dff5ed;
    color: #006b55;
    border-radius: 999px;
    padding: 0.35rem 0.9rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

h1,
h2,
h3,
h4 {
    margin-top: 0;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

h1 {
    font-size: clamp(1.9rem, 4vw, 3rem);
}

.hero-actions {
    display: flex;
    gap: 0.8rem;
    margin-top: 1.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    text-decoration: none;
    border: 1px solid transparent;
    background: linear-gradient(145deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 0.7rem 1.2rem;
    border-radius: 10px;
    cursor: pointer;
    font-weight: 600;
    box-shadow: 0 10px 18px rgba(0, 119, 204, 0.26);
    transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.btn:hover {
    filter: brightness(0.98);
    transform: translateY(-1px);
    box-shadow: 0 12px 22px rgba(0, 119, 204, 0.32);
}

.btn-outline {
    background: white;
    color: var(--primary);
    border-color: #9bc9ec;
    box-shadow: none;
}

.btn-login {
    background: var(--accent);
    color: #263238;
    box-shadow: none;
}

.hero-card-stack {
    display: grid;
    gap: 1rem;
}

.info-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    border: 1px solid var(--line);
    padding: 1rem 1.2rem;
}

.card-a {
    border-left: 6px solid #40a9ff;
}

.card-b {
    border-left: 6px solid #00b894;
}

.card-c {
    border-left: 6px solid #ffb703;
}

.home-visuals {
    padding-top: 0;
}

.visual-band {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
}

.visual-card {
    border-radius: var(--radius-lg);
    padding: 1rem;
    color: #fff;
    box-shadow: var(--shadow-soft);
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 0.8rem;
}

.visual-copy h3 {
    margin-bottom: 0.4rem;
}

.visual-copy p {
    margin: 0;
    color: rgba(255, 255, 255, 0.92);
    font-size: 0.92rem;
}

.visual-card img {
    width: 92px;
    height: auto;
}

.visual-card-a {
    background: linear-gradient(140deg, #0e6dbf, #21a4f0);
}

.visual-card-b {
    background: linear-gradient(140deg, #168b78, #24c36d);
}

.visual-card-c {
    background: linear-gradient(140deg, #8b5ad8, #cf76ff);
}

.book-grid,
.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.2rem;
}

.book-card,
.panel {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.book-card {
    border: 1px solid #d8e9f7;
    display: flex;
    flex-direction: column;
    min-height: 100%;
    transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
}

.book-card:hover {
    transform: translateY(-4px);
    border-color: #a8d1f2;
    box-shadow: 0 16px 28px rgba(12, 45, 74, 0.14);
}

.book-card-media {
    position: relative;
    background: linear-gradient(160deg, #e5f3ff, #f6fbff);
    padding: 0.7rem;
}

.book-card-media img {
    width: 100%;
    aspect-ratio: 3 / 4;
    object-fit: cover;
    border-radius: 10px;
    border: 1px solid #cce2f3;
}

.book-badge {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background: rgba(9, 70, 120, 0.9);
    color: #fff;
    border-radius: 999px;
    padding: 0.2rem 0.58rem;
    font-size: 0.75rem;
    font-weight: 700;
    max-width: calc(100% - 2rem);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.book-card-content {
    padding: 0.95rem 1rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
    flex: 1;
}

.book-card-content h2,
.book-card-content h3 {
    font-size: 1.06rem;
    margin: 0;
}

.book-title {
    color: #16324f;
    line-height: 1.34;
    min-height: 2.7em;
}

.book-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
}

.book-chip {
    border: 1px solid #c3def2;
    background: #f1f8ff;
    color: #1a5684;
    border-radius: 999px;
    padding: 0.18rem 0.62rem;
    font-size: 0.79rem;
    font-weight: 600;
}

.book-isbn {
    margin: 0;
    color: var(--muted);
    font-size: 0.88rem;
}

.book-card-footer {
    margin-top: auto;
    padding-top: 0.3rem;
    border-top: 1px dashed #d8e8f6;
}

.text-link {
    font-weight: 600;
    text-decoration: none;
}

.two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.2rem;
}

.panel {
    padding: 1.2rem;
    border: 1px solid var(--line);
    background: linear-gradient(180deg, var(--surface) 0%, var(--surface-soft) 100%);
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
    padding: 0;
    list-style: none;
}

.tag-list li {
    list-style: none;
}

.tag-link {
    display: inline-block;
    background: #e5f2ff;
    color: #0b4f86;
    padding: 0.4rem 0.7rem;
    border-radius: 999px;
    font-size: 0.93rem;
    text-decoration: none;
    border: 1px solid #c8dff1;
    transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.tag-link:hover {
    background: #0b4f86;
    color: #ffffff;
    transform: translateY(-1px);
}

.cta-strip {
    background: linear-gradient(135deg, #0f4c81, #0077cc);
    color: white;
    box-shadow: var(--shadow-soft);
}

.cta-strip .btn {
    background: white;
    color: #0f4c81;
}

.cta-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.2rem;
}

.page-head {
    padding-bottom: 1.3rem;
}

.about-hero-band {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 1rem;
    align-items: center;
    background: linear-gradient(135deg, #0e66b2, #16b5b2);
    border-radius: var(--radius-lg);
    padding: clamp(1rem, 2vw, 1.5rem);
    color: #fff;
    box-shadow: var(--shadow-soft);
}

.about-hero-band img {
    width: min(100%, 320px);
    margin-left: auto;
}

.about-hero-copy p {
    color: rgba(255, 255, 255, 0.92);
}

.about-fact-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
}

.about-compact-grid {
    gap: 0.65rem;
}

.about-fact-card {
    min-height: 100%;
}

.about-fact-number {
    font-size: 2rem;
    font-weight: 800;
    margin: 0.1rem 0 0.4rem;
    color: #0f6bac;
}

.about-illustrated {
    display: grid;
    place-items: center;
}

.about-illustrated img {
    width: min(100%, 420px);
}

.contact-hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    align-items: stretch;
}

.contact-info-card {
    background: linear-gradient(180deg, #ffffff 0%, #f4faff 100%);
}

.contact-info-full {
    width: 100%;
}

.contact-points-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0.9rem 1rem;
    margin-top: 0.6rem;
}

.contact-point {
    display: grid;
    grid-template-columns: 38px 1fr;
    gap: 0.7rem;
    align-items: start;
    margin-bottom: 0.85rem;
}

.contact-point img {
    width: 38px;
    height: 38px;
}

.contact-point p {
    margin: 0;
}

.contact-hero-art {
    border-radius: var(--radius-lg);
    background: linear-gradient(140deg, #e9f6ff, #eafff3);
    border: 1px solid var(--line);
    display: grid;
    place-items: center;
    padding: 1rem;
}

.contact-hero-art img {
    width: min(100%, 420px);
}

.contact-map-image {
    margin-top: 0.8rem;
    border-radius: 12px;
    border: 1px solid #d7e9f6;
    background: #f8fcff;
}

.filter-form {
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 0.9rem;
    margin-bottom: 1.1rem;
}

.filter-form label {
    font-weight: 600;
    font-size: 0.95rem;
}

input,
select,
textarea {
    width: 100%;
    border: 1px solid #bdd8ed;
    border-radius: 10px;
    padding: 0.65rem 0.7rem;
    margin-top: 0.35rem;
    font: inherit;
    background: #fff;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: #76b4e4;
    box-shadow: 0 0 0 4px rgba(0, 119, 204, 0.14);
}

textarea {
    resize: vertical;
}

.result-meta {
    color: var(--muted);
    font-size: 0.95rem;
}

.pagination {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    margin-top: 1.4rem;
}

.pagination a {
    display: inline-block;
    min-width: 36px;
    text-align: center;
    text-decoration: none;
    border: 1px solid #bdd8ed;
    padding: 0.4rem 0.6rem;
    border-radius: 8px;
    color: var(--text);
    transition: all 0.2s ease;
}

.pagination a:hover {
    background: #edf6ff;
    border-color: #9ec8e8;
}

.pagination a.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.details-layout {
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 1.4rem;
}

.details-cover {
    border-radius: var(--radius);
    width: 100%;
    box-shadow: var(--shadow);
}

.download-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-top: 1rem;
}

.video-wrap {
    position: relative;
    padding-top: 56.25%;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.video-wrap iframe {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

.sub-section {
    margin-top: 2rem;
}

.chapter-list {
    display: grid;
    gap: 0.9rem;
}

.inline-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.inline-links a {
    text-decoration: none;
    font-weight: 600;
}

.site-footer {
    background: #0d2f4c;
    color: #d4e7f7;
    padding: 3rem 0 1rem;
    margin-top: clamp(2rem, 4vw, 3.2rem);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 1rem;
}

.site-footer h3,
.site-footer h4 {
    color: #ffffff;
}

.site-footer a {
    color: #b5d8f4;
    text-decoration: none;
}

.site-footer ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.copyright {
    margin: 1rem auto 0;
    width: min(1120px, 92%);
    border-top: 1px solid rgba(181, 216, 244, 0.35);
    padding-top: 1rem;
    color: #99bfdc;
}

.muted {
    color: var(--muted);
}

.empty-state {
    background: #eef6ff;
    padding: 0.9rem;
    border-radius: 10px;
}

.alert {
    border-radius: 10px;
    padding: 0.8rem;
    margin-bottom: 0.8rem;
}

.alert p {
    margin: 0.2rem 0;
}

.alert-error {
    background: #fef3f2;
    border: 1px solid #fecdca;
    color: var(--danger);
}

.alert-success {
    background: #ecfdf3;
    border: 1px solid #abefc6;
    color: var(--success);
}

@media (max-width: 980px) {
    .hero-grid,
    .two-col,
    .details-layout,
    .footer-grid {
        grid-template-columns: 1fr;
    }

    .book-grid,
    .feature-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .filter-form {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .cta-inner {
        flex-direction: column;
        align-items: flex-start;
    }

    .slider-track { min-height: clamp(170px, 32vw, 320px); }

    .slide-inner {
        grid-template-columns: 1fr;
        text-align: left;
    }

    .slide-copy {
        max-width: 640px;
    }

    .visual-band {
        grid-template-columns: 1fr;
    }

    .about-hero-band,
    .contact-hero-grid,
    .about-fact-grid {
        grid-template-columns: 1fr;
    }

    .contact-points-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .about-hero-band img {
        margin: 0 auto;
    }

}

@media (max-width: 720px) {
    .menu-toggle {
        display: inline-flex;
    }

    .main-nav {
        position: absolute;
        top: 74px;
        left: 0;
        right: 0;
        display: none;
        flex-direction: column;
        align-items: flex-start;
        background: #fff;
        border-top: 1px solid #d5e7f6;
        padding: 1rem 4%;
    }

    .logo-image {
        width: min(360px, 72vw);
        max-height: 58px;
    }

    .main-nav.is-open {
        display: flex;
    }

    .book-grid,
    .feature-grid,
    .filter-form {
        grid-template-columns: 1fr;
    }

    .slider-track { min-height: 430px; }

    .slider-nav {
        width: 36px;
        height: 36px;
    }

    .slider-nav.prev {
        left: 0.5rem;
    }

    .slider-nav.next {
        right: 0.5rem;
    }

    .slide {
        padding: 1rem 0 2rem;
    }

    .slide-copy h2 {
        font-size: 1.55rem;
    }

    .slide-copy p {
        font-size: 0.95rem;
    }

    .contact-points-grid {
        grid-template-columns: 1fr;
    }
}