:root {
    --ink: #172033;
    --muted: #64748b;
    --paper: #f7f9fc;
    --surface: #ffffff;
    --line: #dbe4ef;
    --brand: #0f766e;
    --brand-dark: #115e59;
    --accent: #f59e0b;
    --shadow: 0 18px 45px rgba(23, 32, 51, 0.09);
}

html {
    scroll-behavior: smooth;
}

body {
    background: var(--paper) !important;
    color: var(--ink) !important;
    font-family: "Poppins", "Segoe UI", sans-serif !important;
    line-height: 1.65;
    text-align: left !important;
    padding: 0 !important;
}

header {
    background: rgba(255, 255, 255, 0.94) !important;
    border-bottom: 1px solid var(--line);
    border-radius: 0 !important;
    box-shadow: 0 4px 20px rgba(23, 32, 51, 0.06) !important;
    color: var(--ink) !important;
    padding: 18px 5vw !important;
    position: relative;
    top: auto;
    z-index: 10;
}

header .logo {
    color: var(--brand-dark) !important;
    font-size: 1.15rem !important;
    letter-spacing: 0.01em;
    margin-bottom: 10px !important;
}

header nav ul {
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 6px !important;
    justify-content: center !important;
    list-style: none;
    margin: 0;
    padding: 0;
}

header nav {
    display: flex;
    justify-content: center;
    width: 100%;
}

header nav ul li a {
    border-radius: 8px !important;
    color: var(--muted) !important;
    display: block;
    font-size: 0.9rem;
    min-height: 36px;
    padding: 7px 11px !important;
    white-space: nowrap;
}

header nav ul li a:hover,
header nav ul li a:focus-visible {
    background: #e6f4f1 !important;
    color: var(--brand-dark) !important;
}

main,
.notes-page {
    margin: 0 auto;
    max-width: 1120px;
    padding: 64px 24px 32px;
}

.hero-text,
.notes-hero {
    background: linear-gradient(135deg, #e7f6f2 0%, #fff8e8 100%);
    border: 1px solid #cfe9e3;
    border-radius: 24px;
    margin-bottom: 42px;
    padding: clamp(28px, 6vw, 62px);
    position: relative;
    overflow: hidden;
}

.hero-text::after,
.notes-hero::after {
    border: 1px solid rgba(15, 118, 110, 0.16);
    border-radius: 50%;
    content: "";
    height: 220px;
    position: absolute;
    right: -70px;
    top: -90px;
    width: 220px;
}

.hero-text h1,
.notes-hero h1,
main h1 {
    color: var(--ink) !important;
    font-size: clamp(2rem, 5vw, 3.45rem) !important;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin: 0 0 12px !important;
    position: relative;
    text-align: left !important;
    text-shadow: none !important;
    z-index: 1;
}

.hero-text p,
.notes-hero p,
.intro-text {
    color: var(--muted) !important;
    font-size: 1.05rem !important;
    margin: 0 !important;
    position: relative;
    z-index: 1;
}

.notes-container {
    display: grid;
    gap: 18px !important;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    margin: 0 0 40px !important;
}

.note {
    background: var(--surface) !important;
    border: 1px solid var(--line);
    border-left: 4px solid var(--brand) !important;
    border-radius: 14px !important;
    box-shadow: var(--shadow) !important;
    color: var(--ink) !important;
    padding: 24px !important;
    text-align: left !important;
    transition: border-color 180ms ease, box-shadow 180ms ease, transform 180ms ease;
}

.note:hover {
    border-color: #8acfc5;
    box-shadow: 0 22px 50px rgba(15, 118, 110, 0.14) !important;
    transform: translateY(-4px) !important;
}

.note h2,
.note h3 {
    color: var(--ink) !important;
    font-size: 1.12rem !important;
    line-height: 1.35;
    margin: 0 0 10px !important;
}

.note p {
    color: var(--muted) !important;
    font-size: 0.94rem;
    line-height: 1.65;
    margin: 0 0 18px;
}

.download-btn,
.note-links a {
    background: var(--brand) !important;
    border-radius: 8px !important;
    color: #fff !important;
    display: inline-flex !important;
    font-size: 0.88rem !important;
    font-weight: 600;
    justify-content: center;
    margin-top: 10px;
    padding: 10px 15px !important;
    text-decoration: none;
    transition: background 180ms ease, transform 180ms ease;
}

.download-btn:hover,
.download-btn:focus-visible,
.note-links a:hover,
.note-links a:focus-visible {
    background: var(--brand-dark) !important;
    transform: translateY(-2px);
}

main h2,
.notes-page > h2 {
    border: 0 !important;
    color: var(--ink) !important;
    display: block !important;
    font-size: clamp(1.35rem, 3vw, 1.85rem) !important;
    margin: 42px 0 18px !important;
    padding: 0 !important;
}

.about-notes,
.why-use-section,
.seo-copy {
    background: var(--surface) !important;
    border: 1px solid var(--line);
    border-radius: 16px !important;
    box-shadow: 0 10px 30px rgba(23, 32, 51, 0.05);
    color: var(--muted) !important;
    margin: 0 0 38px !important;
    padding: clamp(22px, 4vw, 34px) !important;
    text-align: left !important;
}

.about-notes h2,
.why-use-section h2,
.seo-copy h2 {
    color: var(--ink) !important;
    margin: 0 0 14px !important;
}

.about-notes p,
.why-use-section p,
.seo-copy p,
.seo-copy li {
    color: var(--muted) !important;
    line-height: 1.8;
    margin-bottom: 14px;
}

.about-notes ul,
.why-use-section ul,
.seo-copy ul {
    padding-left: 20px;
}

.about-notes strong,
.why-use-section strong,
.seo-copy strong {
    color: var(--brand-dark);
}

.subject-nav {
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    margin: 0 0 34px;
}

.subject-nav a {
    background: #e6f4f1;
    border-radius: 999px;
    color: var(--brand-dark);
    display: inline-flex;
    font-size: 0.88rem;
    font-weight: 600;
    justify-content: center;
    min-height: 36px;
    padding: 8px 13px;
    text-align: center;
    text-decoration: none;
}

.subject-nav a:hover,
.subject-nav a:focus-visible {
    background: #cfe9e3;
}

footer {
    background: #172033 !important;
    border-radius: 0 !important;
    color: #dce6f0 !important;
    margin-top: 30px !important;
    padding: 28px 24px !important;
    text-align: center;
}

footer a {
    color: #a7e4db !important;
}

@media (max-width: 640px) {
    header {
        padding: 15px 18px !important;
    }

    header nav ul {
        justify-content: center !important;
    }

    main,
    .notes-page {
        padding: 34px 16px 20px;
    }

    .hero-text,
    .notes-hero {
        border-radius: 18px;
        margin-bottom: 28px;
        padding: 28px 22px;
    }

    .note {
        padding: 20px !important;
    }
}