:root {
    --primary: #0f172a;
    --accent: #3b82f6;
    --accent-dark: #2563eb;
    --text: #334155;
    --light: #f8fafc;
    --white: #ffffff;
    --transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    color: var(--text);
    background-color: var(--white);
    line-height: 1.7;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    padding: 1.2rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(0,0,0,0.05);
}

.header__content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: -1px;
}

.logo span { color: var(--accent); }

.nav__list {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

.nav__link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

.nav__link:hover { color: var(--accent); }

/* Auth Buttons in Header */
.header__auth {
    display: flex;
    align-items: center;
    gap: 1rem;
}

#user-status {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary);
}

.hidden {
    display: none !important;
}

/* Hero Section */
.hero {
    padding: 12rem 0 8rem;
    background: radial-gradient(circle at top right, #f1f5f9 0%, #ffffff 100%);
    text-align: center;
}

.hero__badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: rgba(59, 130, 246, 0.1);
    color: var(--accent);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.hero h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    color: var(--primary);
    line-height: 1.1;
    margin-bottom: 1.5rem;
    letter-spacing: -2px;
}

.hero p {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 2.5rem;
    color: var(--text);
}

.hero__btns {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Buttons */
.btn {
    padding: 1rem 2rem;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
    border: none;
    font-family: inherit;
}

.btn--primary {
    background: var(--accent);
    color: white;
}

.btn--primary:hover {
    background: var(--accent-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(59, 130, 246, 0.3);
}

.btn--outline {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
}

.btn--outline:hover {
    background: var(--primary);
    color: white;
}

.btn--card {
    width: 100%;
    background: var(--primary);
    color: white;
    margin-top: 1.5rem;
}

/* Courses */
.courses {
    padding: 8rem 0;
    background: var(--light);
}

.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 4rem;
    color: var(--primary);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.course-card {
    background: var(--white);
    padding: 2.5rem;
    border-radius: 24px;
    border: 1px solid rgba(0,0,0,0.03);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: var(--transition);
}

.course-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.05);
}

.course-tag {
    color: var(--accent);
    font-weight: 700;
    font-size: 0.8rem;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}

.price {
    display: block;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
    margin-top: 1.5rem;
}

/* Teachers */
.teachers { padding: 8rem 0; }

.teachers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 3rem;
}

.teacher-card {
    border-radius: 24px;
    overflow: hidden;
    background: var(--white);
}

.teacher-card__img {
    height: 350px;
    overflow: hidden;
    border-radius: 24px;
    margin-bottom: 1.5rem;
}

.teacher-card__img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.teacher-card:hover img { transform: scale(1.05); }

.teacher-card__spec {
    color: var(--accent);
    font-weight: 600;
    font-size: 0.9rem;
}

/* Modal Styling */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(5px);
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: var(--white);
    padding: 3rem;
    border-radius: 24px;
    width: 90%;
    max-width: 450px;
    position: relative;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.close-modal {
    position: absolute;
    right: 20px;
    top: 15px;
    font-size: 28px;
    color: var(--text);
    cursor: pointer;
    transition: var(--transition);
}

.close-modal:hover { color: var(--accent); }

.auth-form h3 {
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    color: var(--primary);
}

.auth-form input {
    width: 100%;
    padding: 1rem;
    margin: 0.5rem 0 1.5rem;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition);
}

.auth-form input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

/* Footer */
.footer {
    background: var(--primary);
    color: white;
    padding: 5rem 0;
}

.footer .logo { color: white; margin-bottom: 1.5rem; }

/* Burger Menu */
.burger {
    display: none;
    flex-direction: column;
    gap: 6px;
    background: none;
    border: none;
    cursor: pointer;
}

.burger span {
    width: 30px;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
}

@media (max-width: 768px) {
    .nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: white;
        padding: 2rem;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    }
    .nav--active { display: block; }
    .nav__list { flex-direction: column; text-align: center; }
    .burger { display: flex; }
    .header__auth { margin-right: 15px; }
}

/* About Section Styles */
.about {
    padding: 8rem 0;
    background: #fff;
    overflow: hidden;
}

.about__wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.about__title {
    font-size: 2.5rem;
    line-height: 1.2;
    margin: 1rem 0 1.5rem;
    color: var(--primary);
}

.about__text {
    margin-bottom: 1.5rem;
    color: var(--text);
    font-size: 1.1rem;
}

.about__stats {
    display: flex;
    gap: 2rem;
    margin-top: 3rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent);
}

.stat-desc {
    font-size: 0.9rem;
    color: var(--text);
    font-weight: 500;
}

.about__image {
    position: relative;
}

.about__image img {
    width: 100%;
    border-radius: 30px;
    box-shadow: 20px 20px 60px rgba(0,0,0,0.1);
}

.about__experience-badge {
    position: absolute;
    bottom: -20px;
    left: -20px;
    background: var(--accent);
    color: white;
    padding: 2rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.4);
}

.about__experience-badge strong {
    display: block;
    font-size: 1.8rem;
    line-height: 1;
}

.about__experience-badge span {
    font-size: 0.9rem;
}