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

:root {
    --color-bg: #f5f5f7;
    --color-bg-secondary: #e8e8ed;
    --color-surface: #ffffff;
    --color-text: #1d1d1f;
    --color-text-secondary: #6e6e73;
    --color-text-tertiary: #86868b;
    --color-accent: #0071e3;
    --color-accent-hover: #0077ED;
    --color-accent-secondary: #5856d6;
    --color-border: #d2d2d7;
    --color-border-light: #e8e8ed;
    --color-success: #34c759;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.08);
    --shadow-xl: 0 12px 40px rgba(0, 0, 0, 0.1);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --transition: 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ==================== NAV ==================== */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 0 24px;
    height: 52px;
    display: flex;
    align-items: center;
    background: rgba(245, 245, 247, 0.72);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--color-border-light);
    transition: var(--transition);
}

.nav--scrolled {
    background: rgba(245, 245, 247, 0.92);
    box-shadow: var(--shadow-sm);
}

.nav__container {
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav__logo {
    text-decoration: none;
    color: var(--color-text);
}

.nav__logo-text {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.nav__links {
    display: flex;
    gap: 32px;
}

.nav__link {
    text-decoration: none;
    color: var(--color-text-secondary);
    font-size: 13px;
    font-weight: 400;
    transition: color var(--transition);
    letter-spacing: 0.01em;
}

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

.nav__actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

/* Language Switcher */

.lang-switcher {
    position: relative;
}

.lang-switcher__btn {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 6px 10px;
    background: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: var(--font);
    font-size: 12px;
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: var(--transition);
    letter-spacing: 0.04em;
}

.lang-switcher__btn:hover {
    border-color: var(--color-text-tertiary);
    color: var(--color-text);
}

.lang-switcher__arrow {
    transition: transform var(--transition);
}

.lang-switcher--open .lang-switcher__arrow {
    transform: rotate(180deg);
}

.lang-switcher__dropdown {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    min-width: 160px;
    background: var(--color-surface);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    padding: 6px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: var(--transition);
    max-height: 320px;
    overflow-y: auto;
}

.lang-switcher--open .lang-switcher__dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-switcher__option {
    display: block;
    width: 100%;
    padding: 8px 12px;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: var(--font);
    font-size: 13px;
    color: var(--color-text);
    text-align: left;
    transition: background var(--transition);
}

.lang-switcher__option:hover {
    background: var(--color-bg);
}

.lang-switcher__option--active {
    background: var(--color-bg-secondary);
    font-weight: 500;
}

/* Mobile Menu */

.nav__menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    background: transparent;
    border: none;
    cursor: pointer;
}

.nav__menu-btn span {
    display: block;
    width: 18px;
    height: 1.5px;
    background: var(--color-text);
    transition: var(--transition);
    border-radius: 1px;
}

.nav__menu-btn--active span:first-child {
    transform: rotate(45deg) translate(2px, 2px);
}

.nav__menu-btn--active span:last-child {
    transform: rotate(-45deg) translate(2px, -2px);
}

/* ==================== HERO ==================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 120px 24px 80px;
    position: relative;
    overflow: hidden;
}

.hero__container {
    max-width: 800px;
    position: relative;
    z-index: 2;
}

.hero__badge {
    display: inline-block;
    padding: 6px 16px;
    background: var(--color-bg-secondary);
    border-radius: 100px;
    font-size: 12px;
    font-weight: 500;
    color: var(--color-text-secondary);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 32px;
}

.hero__title {
    font-size: clamp(64px, 10vw, 96px);
    font-weight: 700;
    letter-spacing: -0.04em;
    line-height: 1;
    margin-bottom: 12px;
    background: linear-gradient(135deg, var(--color-text) 0%, var(--color-text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero__phonetic {
    font-size: 18px;
    color: var(--color-accent);
    font-weight: 400;
    letter-spacing: 0.08em;
    margin-bottom: 24px;
    font-style: italic;
}

.hero__subtitle {
    font-size: clamp(24px, 3.5vw, 32px);
    font-weight: 500;
    color: var(--color-text);
    letter-spacing: -0.02em;
    margin-bottom: 20px;
}

.hero__description {
    font-size: 17px;
    color: var(--color-text-secondary);
    max-width: 560px;
    margin: 0 auto 40px;
    line-height: 1.7;
    font-weight: 400;
}

.hero__cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.hero__visual {
    position: absolute;
    inset: 0;
    z-index: 1;
    pointer-events: none;
}

.hero__grid {
    position: absolute;
    inset: 0;
    display: flex;
    justify-content: space-evenly;
    opacity: 0.3;
}

.hero__grid-line {
    width: 1px;
    height: 100%;
    background: linear-gradient(to bottom, transparent 0%, var(--color-border) 30%, var(--color-border) 70%, transparent 100%);
}

/* ==================== BUTTONS ==================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: 980px;
    font-family: var(--font);
    font-size: 15px;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: all var(--transition);
    letter-spacing: -0.01em;
}

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

.btn--primary:hover {
    background: var(--color-accent-hover);
    box-shadow: 0 4px 16px rgba(0, 113, 227, 0.3);
    transform: translateY(-1px);
}

.btn--secondary {
    background: transparent;
    color: var(--color-accent);
    border: 1px solid var(--color-border);
}

.btn--secondary:hover {
    background: var(--color-bg-secondary);
    border-color: var(--color-text-tertiary);
}

.btn--full {
    width: 100%;
}

/* ==================== SECTIONS ==================== */

.section__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section__header {
    text-align: center;
    margin-bottom: 64px;
}

.section__label {
    display: inline-block;
    font-size: 13px;
    font-weight: 500;
    color: var(--color-accent);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 16px;
}

.section__title {
    font-size: clamp(32px, 5vw, 48px);
    font-weight: 600;
    letter-spacing: -0.03em;
    line-height: 1.15;
    color: var(--color-text);
}

/* ==================== PHILOSOPHY ==================== */

.philosophy {
    padding: 120px 0;
    background: var(--color-surface);
}

.philosophy__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.philosophy__card {
    padding: 40px 32px;
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition);
}

.philosophy__card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    border-color: var(--color-border);
}

.philosophy__card-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-accent);
    margin-bottom: 24px;
}

.philosophy__card-title {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: 12px;
    color: var(--color-text);
}

.philosophy__card-text {
    font-size: 15px;
    color: var(--color-text-secondary);
    line-height: 1.65;
}

/* ==================== RESEARCH ==================== */

.research {
    padding: 120px 0;
}

.research__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.research__card {
    padding: 36px 32px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.research__card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    border-color: var(--color-border);
}

.research__card-number {
    display: block;
    font-size: 12px;
    font-weight: 600;
    color: var(--color-accent);
    letter-spacing: 0.08em;
    margin-bottom: 16px;
}

.research__card-title {
    font-size: 20px;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: 12px;
    color: var(--color-text);
}

.research__card-text {
    font-size: 15px;
    color: var(--color-text-secondary);
    line-height: 1.65;
    margin-bottom: 20px;
}

.research__card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--color-bg);
    border-radius: 100px;
    font-size: 12px;
    font-weight: 500;
    color: var(--color-text-tertiary);
    border: 1px solid var(--color-border-light);
}

/* ==================== CONTACT ==================== */

.contact {
    padding: 120px 0;
    background: var(--color-surface);
}

.contact__layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: start;
}

.contact__text {
    font-size: 16px;
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 40px;
}

.contact__details {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact__detail {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.contact__detail-label {
    font-size: 12px;
    font-weight: 500;
    color: var(--color-text-tertiary);
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.contact__detail-value {
    font-size: 15px;
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
}

a.contact__detail-value:hover {
    color: var(--color-accent);
}

/* Form */

.contact__form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form__group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form__label {
    font-size: 13px;
    font-weight: 500;
    color: var(--color-text);
}

.form__input {
    padding: 12px 16px;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font);
    font-size: 15px;
    color: var(--color-text);
    transition: border-color var(--transition), box-shadow var(--transition);
    outline: none;
    width: 100%;
}

.form__input:focus {
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(0, 113, 227, 0.12);
}

.form__input::placeholder {
    color: var(--color-text-tertiary);
}

.form__select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%236e6e73' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
    cursor: pointer;
}

.form__textarea {
    resize: vertical;
    min-height: 120px;
}

.form__success {
    display: none;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: rgba(52, 199, 89, 0.08);
    border: 1px solid rgba(52, 199, 89, 0.2);
    border-radius: var(--radius-sm);
    color: var(--color-success);
}

.form__success--visible {
    display: flex;
}

.form__success p {
    font-size: 14px;
    font-weight: 500;
}

/* ==================== FOOTER ==================== */

.footer {
    padding: 48px 0;
    border-top: 1px solid var(--color-border-light);
}

.footer__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.footer__top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 32px;
}

.footer__logo {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--color-text);
}

.footer__tagline {
    font-size: 13px;
    color: var(--color-text-tertiary);
    margin-top: 4px;
}

.footer__links {
    display: flex;
    gap: 24px;
}

.footer__link {
    text-decoration: none;
    color: var(--color-text-secondary);
    font-size: 13px;
    transition: color var(--transition);
}

.footer__link:hover {
    color: var(--color-text);
}

.footer__bottom {
    padding-top: 24px;
    border-top: 1px solid var(--color-border-light);
}

.footer__copy {
    font-size: 12px;
    color: var(--color-text-tertiary);
}

/* ==================== REVEAL ANIMATION ==================== */

.reveal {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.8s cubic-bezier(0.25, 0.1, 0.25, 1),
                transform 0.8s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.reveal--visible {
    opacity: 1;
    transform: translateY(0);
}

/* ==================== RESPONSIVE ==================== */

@media (max-width: 1024px) {
    .philosophy__grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .research__grid {
        grid-template-columns: 1fr;
    }

    .contact__layout {
        grid-template-columns: 1fr;
        gap: 48px;
    }
}

@media (max-width: 768px) {
    .nav__links {
        display: none;
        position: fixed;
        top: 52px;
        left: 0;
        right: 0;
        background: rgba(245, 245, 247, 0.96);
        backdrop-filter: saturate(180%) blur(20px);
        -webkit-backdrop-filter: saturate(180%) blur(20px);
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        border-bottom: 1px solid var(--color-border-light);
    }

    .nav__links--open {
        display: flex;
    }

    .nav__menu-btn {
        display: flex;
    }

    .hero {
        padding: 100px 24px 60px;
        min-height: auto;
    }

    .hero__title {
        font-size: 56px;
    }

    .hero__cta {
        flex-direction: column;
        align-items: center;
    }

    .philosophy,
    .research,
    .contact {
        padding: 80px 0;
    }

    .footer__top {
        flex-direction: column;
        gap: 24px;
        text-align: center;
    }

    .footer__links {
        justify-content: center;
    }

    .footer__bottom {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero__title {
        font-size: 44px;
    }

    .section__title {
        font-size: 28px;
    }

    .philosophy__card {
        padding: 28px 24px;
    }

    .research__card {
        padding: 28px 24px;
    }
}

/* ==================== RTL SUPPORT ==================== */

[dir="rtl"] .lang-switcher__dropdown {
    right: auto;
    left: 0;
}

[dir="rtl"] .form__select {
    background-position: left 16px center;
    padding-right: 16px;
    padding-left: 40px;
}