:root {
    --navy: #0b3d5c;
    --teal: #0a5c7a;
    --teal-deep: #074a63;
    --blue: #1a9fd8;
    --blue-bright: #2eb5e8;
    --blue-soft: #e8f5fb;
    --blue-banner: #d6eef8;
    --ink: #1a2b3c;
    --muted: #5a6b7c;
    --line: #e2ebf1;
    --surface: #ffffff;
    --page: #f3f7fa;
    --green: #3cb371;
    --green-soft: #e8f8ef;
    --purple: #7b6cf6;
    --orange: #f0a14a;
    --pink: #e86b9a;
    --teal-accent: #3db8b0;
    --red: #e85a5a;
    --phys-blue: #4aa8d8;
    --shadow: 0 12px 40px rgba(11, 61, 92, 0.12);
    --radius: 14px;
    --font: "Plus Jakarta Sans", system-ui, sans-serif;
    --script: "Caveat", cursive;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font);
    color: var(--ink);
    background:
            radial-gradient(1200px 600px at 85% -10%, rgba(46, 181, 232, 0.16), transparent 55%),
            radial-gradient(900px 500px at -10% 20%, rgba(10, 92, 122, 0.08), transparent 50%),
            linear-gradient(180deg, #f7fbfd 0%, var(--page) 40%, #eef4f8 100%);
    min-height: 100vh;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font: inherit; border: 0; background: none; cursor: pointer; color: inherit; }

/* —— Header —— */
.site-header {
    background: linear-gradient(180deg, var(--teal) 0%, var(--teal-deep) 100%);
    color: #fff;
    position: sticky;
    top: 0;
    z-index: 40;
    box-shadow: 0 2px 16px rgba(7, 74, 99, 0.25);
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0.85rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    flex-shrink: 0;
}

.brand-mark {
    font-size: 1.85rem;
    font-weight: 800;
    letter-spacing: -0.04em;
    line-height: 1;
}

.brand-divider {
    width: 1px;
    height: 1.6rem;
    background: rgba(255, 255, 255, 0.35);
}

.brand-tag {
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    opacity: 0.92;
    line-height: 1.2;
    white-space: nowrap;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 0.15rem;
    list-style: none;
}

.nav-links a,
.nav-links button {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.55rem 0.7rem;
    font-size: 0.92rem;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.92);
    border-radius: 8px;
    transition: background 0.2s, color 0.2s;
}

.nav-links a:hover,
.nav-links button:hover {
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
}

.nav-links .chevron {
    width: 10px;
    height: 10px;
    opacity: 0.75;
}

.search-btn {
    padding: 0.55rem;
    border-radius: 8px;
    display: grid;
    place-items: center;
    color: #fff;
    transition: background 0.2s;
}

.search-btn:hover { background: rgba(255, 255, 255, 0.1); }

.menu-toggle {
    display: none;
    width: 42px;
    height: 42px;
    border-radius: 10px;
    place-items: center;
    background: rgba(255, 255, 255, 0.1);
}

/* —— Hero —— */
.hero {
    position: relative;
    max-width: 1200px;
    margin: 0 auto;
    padding: 3.25rem 1.5rem 2.25rem;
    display: grid;
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 2.5rem;
    align-items: start;
}

.hero-copy {
    position: relative;
    z-index: 2;
    padding-top: 0.35rem;
    animation: rise 0.7s ease both;
}

.hero-brand {
    display: block;
    margin-bottom: 0.85rem;
}

.hero-brand img {
    width: auto;
    height: clamp(2.8rem, 5vw, 3.6rem);
    max-width: min(340px, 100%);
}

.hero-callout {
    position: absolute;
    z-index: 5;
    grid-column: 1 / -1;
    grid-row: 1;
    left: 40%;
    top: 7.25rem;
    width: min(300px, 30vw);
    justify-self: start;
    align-self: start;
    pointer-events: none;
    color: var(--blue);
    animation: drift 4.5s ease-in-out infinite;
}

.hero-callout p {
    font-family: var(--script);
    font-size: clamp(2.4rem, 4.2vw, 3.35rem);
    font-weight: 700;
    line-height: 0.95;
    letter-spacing: -0.01em;
    transform: rotate(-10deg);
    text-shadow:
            0 1px 0 rgba(255, 255, 255, 0.95),
            0 8px 24px rgba(26, 159, 216, 0.2);
}

.hero-callout svg {
    display: block;
    width: min(170px, 100%);
    margin-top: 0.1rem;
    margin-left: 2.75rem;
    overflow: visible;
    filter: drop-shadow(0 2px 0 rgba(255, 255, 255, 0.7));
}

.hero h1 {
    font-size: clamp(1.55rem, 2.6vw, 1.95rem);
    font-weight: 700;
    color: var(--ink);
    letter-spacing: -0.025em;
    line-height: 1.2;
    margin-bottom: 0.45rem;
}

.hero-sub {
    font-size: clamp(1.05rem, 1.8vw, 1.3rem);
    font-weight: 700;
    color: var(--blue);
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
    max-width: 28rem;
    line-height: 1.35;
}

.hero-desc {
    font-size: 1.05rem;
    color: var(--muted);
    max-width: 34rem;
    margin-bottom: 2rem;
    line-height: 1.65;
}

.features {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1rem;
}

.feature {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.65rem;
    animation: rise 0.7s ease both;
}

.feature:nth-child(1) { animation-delay: 0.08s; }
.feature:nth-child(2) { animation-delay: 0.16s; }
.feature:nth-child(3) { animation-delay: 0.24s; }
.feature:nth-child(4) { animation-delay: 0.32s; }

.feature-icon {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    box-shadow: 0 6px 18px rgba(11, 61, 92, 0.1);
    transition: transform 0.25s ease;
}

.feature:hover .feature-icon { transform: translateY(-3px) scale(1.04); }

.feature-icon.place { background: #dff3fb; color: var(--blue); }
.feature-icon.label { background: #e4f7ec; color: var(--green); }
.feature-icon.identify { background: #ece8ff; color: var(--purple); }
.feature-icon.know { background: #fff0de; color: var(--orange); }

.feature strong {
    display: block;
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--navy);
    margin-bottom: 0.15rem;
}

.feature span {
    font-size: 0.78rem;
    color: var(--muted);
    line-height: 1.4;
}

.hero-cta {
    margin-top: 1.75rem;
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: flex-end;
    flex-wrap: wrap;
    gap: 0.85rem 1rem;
    width: 100%;
}

.hero-cta-label {
    font-size: 1.15rem;
    font-weight: 800;
    color: var(--navy);
    letter-spacing: -0.02em;
}

.hero-cta-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.8rem 1.35rem;
    border-radius: 999px;
    background: var(--blue);
    color: #fff;
    font-size: 0.95rem;
    font-weight: 700;
    box-shadow: 0 10px 24px rgba(26, 159, 216, 0.28);
    transition: transform 0.15s ease, background 0.15s ease, box-shadow 0.15s ease;
}

.hero-cta-btn:hover {
    background: #1490c4;
    transform: translateY(-2px);
    box-shadow: 0 14px 28px rgba(26, 159, 216, 0.34);
}

.hero-visual {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 560px;
    margin-left: auto;
    padding-bottom: 7.5rem;
    animation: fade-in 0.9s ease 0.15s both;
}

.hero-visual #ditki-brain-quiz,
.hero-visual .dbq {
    max-width: none;
    margin: 0;
    overflow: visible;
}

.hero-visual .dbq-stage {
    overflow: visible;
    box-shadow: none;
    background: transparent;
}

.hero-visual .dbq-frame {
    box-shadow: var(--shadow);
}

.hero-visual .dbq-card {
    bottom: -7.25rem;
    z-index: 6;
}

/* —— Banner —— */
.announce {
    max-width: 1200px;
    margin: -1.75rem auto 2.5rem;
    padding: 0 1.5rem;
    position: relative;
    z-index: 2;
    animation: rise 0.7s ease 0.25s both;
}

.announce-inner {
    background: linear-gradient(90deg, #d9f0fa 0%, #e7f6fc 50%, #d4eef9 100%);
    border-radius: 16px;
    padding: 1.1rem 1.4rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    border: 1px solid rgba(46, 181, 232, 0.22);
}

.announce-brands {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    flex-shrink: 0;
}

.logo-ditki {
    font-weight: 800;
    font-size: 1.35rem;
    color: var(--teal);
    letter-spacing: -0.03em;
}

.heart-arrow {
    display: flex;
    align-items: center;
    gap: 0.2rem;
    color: var(--blue);
}

.logo-novo {
    display: flex;
    align-items: center;
    line-height: 1;
}

.logo-novo img {
    width: auto;
    height: 44px;
    max-width: 220px;
}

.announce-copy {
    font-size: 0.95rem;
    color: var(--ink);
    max-width: 42rem;
}

.announce-copy a {
    color: var(--blue);
    font-weight: 700;
}

.announce-copy a:hover { text-decoration: underline; }

/* —— Topics —— */
.topics {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0.5rem 1.5rem 3.5rem;
}

.topics h2 {
    text-align: center;
    font-size: clamp(1.8rem, 3vw, 2.25rem);
    font-weight: 800;
    color: var(--navy);
    letter-spacing: -0.03em;
    margin-bottom: 2rem;
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.15rem;
}

.topic-card {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 1.25rem 1.2rem 1.1rem;
    display: flex;
    flex-direction: column;
    min-height: 260px;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
    animation: rise 0.6s ease both;
}

.topic-card .collapse-control, .topic-card .topic-footer .collapse-control {
    display: none;
}

.topic-card:target .collapse-control {
    cursor: pointer;
    display: inline;
}

.topic-card:target .topic-footer .view-all {
    display: none;
}

.topic-card:target .topic-card {
    box-shadow: none;
    display: block;
}

.topic-card:target .more-control {
    display: none;
}

.more .topic-card {
    border: none;
    display: none;
    padding: 0;
}

.topic-card:nth-child(1) { animation-delay: 0.05s; }
.topic-card:nth-child(2) { animation-delay: 0.1s; }
.topic-card:nth-child(3) { animation-delay: 0.15s; }
.topic-card:nth-child(4) { animation-delay: 0.2s; }
.topic-card:nth-child(5) { animation-delay: 0.25s; }
.topic-card:nth-child(6) { animation-delay: 0.3s; }
.topic-card:nth-child(7) { animation-delay: 0.35s; }
.topic-card:nth-child(8) { animation-delay: 0.4s; }

.topic-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 14px 32px rgba(11, 61, 92, 0.1);
    border-color: rgba(46, 181, 232, 0.35);
}

.topic-head {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    margin-bottom: 0.95rem;
}

.topic-head h3 {
    display: flex;
    flex-grow: 1;
    justify-content: space-between;
}

.topic-icon {
    width: 40px;
    height: 40px;
    border-radius: 11px;
    display: grid;
    place-items: center;
    flex-shrink: 0;
}

.topic-card h3 {
    font-size: 1.02rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.topic-card.biochemistry .topic-icon { background: #dff3fb; color: var(--blue); }
.topic-card.biochemistry h3 { color: #178fc4; }
.topic-card.cell-biology .topic-icon { background: #e4f7ec; color: var(--green); }
.topic-card.cell-biology h3 { color: #2d9a5c; }
.topic-card.clinical-medicine-medical-students .topic-icon { background: #ece8ff; color: var(--purple); }
.topic-card.clinical-medicine-medical-students h3 { color: #6a5ce0; }
.topic-card.gross-anatomy .topic-icon { background: #dff3fb; color: var(--blue); }
.topic-card.gross-anatomy h3 { color: #178fc4; }
.topic-card.pathology .topic-icon { background: #fff0de; color: var(--orange); }
.topic-card.pathology h3 { color: #d4892f; }
.topic-card.pharmacology .topic-icon { background: #fde8f1; color: var(--pink); }
.topic-card.pharmacology h3 { color: #d45585; }
.topic-card.embryology .topic-icon { background: #ddf6f4; color: var(--teal-accent); }
.topic-card.embryology h3 { color: #2a9e96; }
.topic-card.histology .topic-icon { background: #e4f7ec; color: var(--green); }
.topic-card.histology h3 { color: #2d9a5c; }
.topic-card.neuroanatomy .topic-icon { background: #fde8e8; color: var(--red); }
.topic-card.neuroanatomy h3 { color: #d24545; }
.topic-card.physiology .topic-icon { background: #e3f3fb; color: var(--phys-blue); }
.topic-card.physiology h3 { color: #2f8fbe; }

.topic-links {
    list-style: none;
    display: grid;
    gap: 0.35rem;
    flex: 1;
    align-content: start;
    margin-bottom: 1rem;
}

.topic-links a {
    font-size: 0.88rem;
    color: var(--muted);
    transition: color 0.15s;
    line-height: 1.35;
}

.topic-links a:hover { color: var(--blue); }

.topic-links .more-control {
    font-size: 0.82rem;
    color: #8a9aab;
    font-weight: 500;
}

.topic-footer .collapse-control, .topic-footer .view-all {
    margin-top: auto;
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--blue);
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    transition: gap 0.2s;
}

.view-all:hover { gap: 0.5rem; }

/* —— Trust bar —— */
.trust {
    background: #e9eef2;
    border-top: 1px solid #dde5eb;
}

.trust-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    font-size: 0.9rem;
    color: var(--muted);
}

.trust-left {
    display: flex;
    align-items: center;
    gap: 0.55rem;
}

.trust-left svg { color: var(--blue); flex-shrink: 0; }

.trust-right strong { color: var(--blue); font-weight: 700; }

/* —— Animations —— */
@keyframes rise {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fade-in {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes drift {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(4px, -5px); }
}

/* —— Responsive —— */
@media (max-width: 1080px) {
    .topic-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .features { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1.25rem; }
}

@media (max-width: 900px) {
    .hero {
        grid-template-columns: 1fr;
        padding-top: 2.25rem;
    }

    .hero-visual {
        max-width: 520px;
        margin: 0 auto;
        width: 100%;
    }

    .hero-callout {
        position: relative;
        grid-column: auto;
        grid-row: auto;
        left: auto;
        top: auto;
        width: auto;
        margin: -0.35rem 0 0.5rem 0.35rem;
        justify-self: start;
        animation: none;
    }

    .hero-callout p {
        font-size: clamp(2.1rem, 8vw, 2.8rem);
    }

    .hero {
        padding-bottom: 3.5rem;
    }

    .hero-visual {
        padding-bottom: 7rem;
    }

    .announce {
        margin-top: -0.75rem;
    }

    .nav-links { display: none; }
    .menu-toggle { display: grid; }

    .nav-links.open {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--teal-deep);
        padding: 0.75rem;
        box-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
    }

    .header-inner { position: relative; }

    .announce-inner {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.85rem;
    }

    .trust-inner {
        flex-direction: column;
        align-items: flex-start;
        text-align: left;
    }
}

@media (max-width: 560px) {
    .topic-grid { grid-template-columns: 1fr; }
    .features { grid-template-columns: 1fr 1fr; }
    .brand-tag, .brand-divider { display: none; }
}