:root {
    --ink: #12212d;
    --muted: #5f6a72;
    --paper: #f8f8f3;
    --sand: #eeece3;
    --blue: #195d78;
    --blue-dark: #10475f;
    --orange: #e86d3e;
    --line: #d8ddd6;
    --white: #ffffff;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    color: var(--ink);
    background: var(--paper);
    font-family: "Manrope", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
}

a { color: inherit; text-decoration: none; }

.container { width: min(1120px, calc(100% - 48px)); margin: 0 auto; }

.site-header { background: rgba(248, 248, 243, .93); border-bottom: 1px solid rgba(18, 33, 45, .08); position: sticky; top: 0; z-index: 10; backdrop-filter: blur(12px); }

.navigation { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 28px; }

.brand { color: var(--ink); font-size: 20px; font-weight: 800; letter-spacing: -.07em; }
.brand span { color: var(--orange); padding: 0 2px; }

.nav-links { display: flex; gap: 28px; font-size: 14px; font-weight: 600; color: #43515b; }
.nav-links a:hover, .text-link:hover, .subject-card a:hover { color: var(--orange); }

.nav-button { padding: 9px 17px; color: var(--blue); border: 1px solid var(--blue); border-radius: 999px; font-size: 13px; font-weight: 700; }
.nav-button:hover { background: var(--blue); color: var(--white); }

.hero { overflow: hidden; padding: 84px 0 74px; background: linear-gradient(115deg, #e8f1ee 0%, #f8f8f3 60%, #f8eee5 100%); }
.hero-grid { display: grid; grid-template-columns: 1.22fr .78fr; align-items: center; gap: 76px; }

.eyebrow, .section-kicker, .card-kicker { margin: 0 0 14px; color: var(--orange); font-size: 12px; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { font-family: "Source Serif 4", Georgia, serif; line-height: 1.08; }
h1 { max-width: 680px; margin-bottom: 24px; font-size: clamp(44px, 5vw, 72px); font-weight: 700; letter-spacing: -.05em; }
h1 em { color: var(--blue); font-style: italic; }
.hero-text { max-width: 595px; margin-bottom: 32px; color: #42515a; font-size: 18px; }

.hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 24px; }
.button { display: inline-block; border: 0; border-radius: 5px; padding: 15px 22px; font: inherit; font-size: 14px; font-weight: 800; cursor: pointer; transition: transform .2s, background .2s; }
.button-primary { color: var(--white); background: var(--orange); box-shadow: 0 8px 20px rgba(232, 109, 62, .18); }
.button-primary:hover { background: #d75f32; transform: translateY(-2px); }
.text-link { color: var(--blue); font-size: 14px; font-weight: 800; }
.text-link span { margin-left: 6px; font-size: 18px; }

.hero-stats { display: flex; gap: 31px; margin-top: 55px; }
.hero-stats div { display: grid; gap: 2px; }
.hero-stats strong { color: var(--blue); font-size: 18px; font-weight: 800; }
.hero-stats span { color: var(--muted); font-size: 11px; }

.formula-card { position: relative; min-height: 420px; overflow: hidden; border-radius: 50% 50% 4% 4%; background: var(--blue); box-shadow: 23px 27px 0 #d5e2dc; }
.formula-card::after { position: absolute; width: 100%; height: 30%; left: 0; bottom: 0; background: #10475f; content: ""; }
.formula-center { position: absolute; top: 50%; left: 50%; z-index: 2; width: 210px; height: 210px; padding-top: 60px; border: 1px solid rgba(255, 255, 255, .45); border-radius: 50%; text-align: center; color: white; transform: translate(-50%, -50%); }
.formula-center p { margin-bottom: 6px; color: #b9d4dc; font-size: 10px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; }
.formula-center strong { font-family: "Source Serif 4", Georgia, serif; font-size: 28px; line-height: 1; }
.card-orbit { position: absolute; top: 50%; left: 50%; border: 1px solid rgba(255, 255, 255, .27); border-radius: 50%; transform: translate(-50%, -50%); }
.orbit-one { width: 310px; height: 310px; }
.orbit-two { width: 465px; height: 465px; }
.formula { position: absolute; z-index: 3; color: #f5c05a; font-family: "Source Serif 4", Georgia, serif; }
.formula-e { top: 64px; left: 48px; font-size: 30px; transform: rotate(-11deg); }
.formula-root { right: 47px; bottom: 80px; font-size: 56px; }
.formula-sum { top: 115px; right: 64px; color: #e88c68; font-size: 62px; }

.section { padding: 110px 0; }
.split-layout { display: grid; grid-template-columns: .72fr 1.28fr; gap: 80px; }
.split-layout h2, .section-heading h2, .process h2, .booking h2 { margin-bottom: 25px; font-size: clamp(36px, 4vw, 54px); letter-spacing: -.045em; }
.split-layout .lead { max-width: 610px; color: var(--blue); font-family: "Source Serif 4", Georgia, serif; font-size: 25px; line-height: 1.35; }
.split-layout p:not(.lead) { max-width: 650px; color: var(--muted); }

.subjects { background: var(--sand); }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 40px; margin-bottom: 46px; }
.section-heading h2 { margin-bottom: 0; }
.section-heading > p { max-width: 350px; margin-bottom: 6px; color: var(--muted); font-size: 14px; }
.subject-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.subject-card { min-height: 351px; padding: 35px; background: var(--white); border-radius: 3px; }
.subject-card.physics-card { border-top: 5px solid var(--blue); }
.subject-card.math-card { border-top: 5px solid var(--orange); }
.subject-icon { display: inline-flex; width: 50px; height: 50px; align-items: center; justify-content: center; margin-bottom: 35px; border-radius: 50%; color: var(--white); background: var(--blue); font-family: "Source Serif 4", Georgia, serif; font-size: 28px; font-weight: 700; }
.math-card .subject-icon { background: var(--orange); }
.subject-card .card-kicker { margin-bottom: 6px; font-size: 10px; }
.subject-card h3 { margin-bottom: 18px; font-size: 34px; letter-spacing: -.04em; }
.subject-card ul { min-height: 90px; margin: 0 0 23px; padding: 0; list-style: none; color: var(--muted); font-size: 13px; }
.subject-card li { padding: 3px 0 3px 18px; position: relative; }
.subject-card li::before { position: absolute; left: 0; color: var(--orange); content: "•"; }
.subject-card a { color: var(--blue); font-size: 13px; font-weight: 800; }
.subject-card a span { padding-left: 4px; }

.process { background: #f2f6f4; }
.process h2 { margin-bottom: 47px; }
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.steps article { position: relative; padding: 30px 25px 10px 0; border-top: 1px solid #aec1bb; }
.steps span { display: block; margin-bottom: 35px; color: var(--orange); font-size: 13px; font-weight: 800; }
.steps h3 { margin-bottom: 11px; font-size: 25px; letter-spacing: -.03em; }
.steps p { color: var(--muted); font-size: 14px; }

.booking { padding: 108px 0; color: var(--white); background: #153545; }
.booking-layout { display: grid; grid-template-columns: .82fr 1.18fr; gap: 70px; align-items: start; }
.booking .section-kicker { color: #f4a483; }
.booking h2 { max-width: 500px; }
.booking-copy > p:not(.section-kicker) { max-width: 415px; color: #c0d0d2; }
.privacy-note { margin-top: 42px; font-size: 12px; }
.privacy-note::before { margin-right: 8px; content: "⌁"; color: #f4a483; }

.form-card { padding: 33px; color: var(--ink); background: var(--white); border-radius: 4px; }
.form-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.field { display: grid; gap: 7px; }
.field.full-width { grid-column: 1 / -1; }
.field label { font-size: 12px; font-weight: 800; }
.form-control { width: 100%; min-height: 43px; padding: 9px 11px; border: 1px solid #ccd4d2; border-radius: 3px; outline: none; color: var(--ink); background: #fdfdfb; font: inherit; font-size: 13px; }
textarea.form-control { min-height: 89px; resize: vertical; }
.form-control:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(25, 93, 120, .12); }
.submit-button { width: 100%; margin-top: 25px; }
.error { color: #b33f26; font-size: 11px; line-height: 1.3; }
.form-errors { margin-bottom: 15px; padding: 11px; color: #8f341f; background: #fce9e4; font-size: 13px; }
.message { margin-bottom: 18px; padding: 13px 15px; font-size: 13px; font-weight: 600; }
.message-success { color: #275c43; background: #e3f2e8; border-left: 3px solid #4b9a71; }

.site-footer { padding: 27px 0; color: #b5c0c3; background: #0f2937; font-size: 12px; }
.footer-content { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.site-footer .brand { color: var(--white); }
.site-footer p { margin: 0; }

@media (max-width: 800px) {
    .nav-links { display: none; }
    .hero { padding: 64px 0; }
    .hero-grid, .booking-layout { grid-template-columns: 1fr; gap: 48px; }
    .formula-card { min-height: 350px; max-width: 500px; width: calc(100% - 20px); margin: 0 auto; }
    .split-layout { grid-template-columns: 1fr; gap: 5px; }
    .section-heading { display: block; }
    .section-heading > p { margin-top: 18px; }
    .section { padding: 78px 0; }
    .booking { padding: 78px 0; }
}

@media (max-width: 560px) {
    .container { width: min(100% - 32px, 1120px); }
    .navigation { min-height: 65px; }
    .nav-button { padding: 7px 12px; }
    h1 { font-size: 43px; }
    .hero-text { font-size: 16px; }
    .hero-stats { gap: 16px; margin-top: 38px; }
    .hero-stats strong { font-size: 15px; }
    .hero-stats span { font-size: 9px; }
    .formula-card { min-height: 300px; }
    .orbit-one { width: 245px; height: 245px; }
    .orbit-two { width: 365px; height: 365px; }
    .formula-e { top: 40px; left: 28px; }
    .formula-sum { top: 66px; right: 35px; }
    .formula-root { right: 28px; bottom: 48px; }
    .subject-grid, .steps, .form-grid { grid-template-columns: 1fr; }
    .subject-card { min-height: auto; }
    .subject-card ul { min-height: auto; }
    .steps { gap: 12px; }
    .steps span { margin-bottom: 18px; }
    .form-card { padding: 22px 18px; }
    .footer-content { align-items: flex-start; flex-direction: column; gap: 7px; }
}