/* ========================================
   SkillSync — Design System & Styles
   ======================================== */

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --color-primary: #6C5CE7;
    --color-primary-dark: #5A4BD1;
    --color-primary-light: #A29BFE;
    --color-accent: #00B894;
    --color-accent-dark: #00A381;
    --color-text: #1a1a2e;
    --color-text-secondary: #555770;
    --color-text-muted: #8B8DA3;
    --color-bg: #ffffff;
    --color-bg-alt: #F8F9FC;
    --color-bg-dark: #0F0E17;
    --color-border: #E4E5F1;
    --color-surface: #ffffff;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.12);
    --shadow-xl: 0 24px 64px rgba(0,0,0,0.16);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.skip-link {
    position: absolute;
    top: -100%;
    left: 16px;
    background: var(--color-primary);
    color: #fff;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    z-index: 1000;
    font-weight: 600;
}
.skip-link:focus { top: 16px; }

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Typography --- */
h1, h2, h3, h4 { line-height: 1.15; font-weight: 800; letter-spacing: -0.02em; }
h1 { font-size: clamp(2.5rem, 5vw + 1rem, 4.5rem); }
h2 { font-size: clamp(2rem, 3vw + 0.5rem, 3rem); }
h3 { font-size: 1.25rem; }

.gradient-text {
    background: linear-gradient(135deg, var(--color-primary) 0%, #A29BFE 50%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-sans);
    font-weight: 600;
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    white-space: nowrap;
}
.btn:focus-visible { outline: 3px solid var(--color-primary-light); outline-offset: 2px; }
.btn--sm { padding: 8px 16px; font-size: 0.875rem; }
.btn--lg { padding: 14px 28px; font-size: 1.05rem; }
.btn--full { width: 100%; justify-content: center; padding: 14px 24px; font-size: 1rem; }

.btn--primary {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}
.btn--primary:hover { background: var(--color-primary-dark); border-color: var(--color-primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-md); }

.btn--outline {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border);
}
.btn--outline:hover { border-color: var(--color-primary); color: var(--color-primary); }

.btn--ghost { background: transparent; color: var(--color-text-secondary); }
.btn--ghost:hover { color: var(--color-primary); }

.btn--white {
    background: #fff;
    color: var(--color-primary);
    border-color: #fff;
    font-weight: 700;
}
.btn--white:hover { background: #f0eeff; transform: translateY(-1px); box-shadow: var(--shadow-md); }

.btn--ghost-white {
    background: transparent;
    color: rgba(255,255,255,0.9);
    border-color: rgba(255,255,255,0.3);
}
.btn--ghost-white:hover { border-color: #fff; color: #fff; }

/* --- Header/Nav --- */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--color-border);
    transition: background var(--transition);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 24px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    font-size: 1.2rem;
    color: var(--color-text);
}
.logo svg { flex-shrink: 0; }

.nav-links {
    display: flex;
    gap: 32px;
}
.nav-links a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: color var(--transition);
    position: relative;
}
.nav-links a:hover { color: var(--color-primary); }
.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    border-radius: 1px;
    transition: width var(--transition);
}
.nav-links a:hover::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 8px; }

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}
.mobile-toggle span {
    width: 22px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all var(--transition);
}

/* --- Hero --- */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(180deg, #F8F9FC 0%, #fff 100%);
    overflow: hidden;
}

.hero__inner {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.hero__badge {
    display: inline-block;
    background: rgba(108, 92, 231, 0.08);
    color: var(--color-primary);
    font-size: 0.875rem;
    font-weight: 600;
    padding: 6px 16px;
    border-radius: 100px;
    margin-bottom: 24px;
    border: 1px solid rgba(108, 92, 231, 0.15);
}

.hero__title { margin-bottom: 20px; color: var(--color-text); }

.hero__subtitle {
    font-size: 1.2rem;
    color: var(--color-text-secondary);
    max-width: 500px;
    margin-bottom: 32px;
    line-height: 1.7;
}

.hero__cta { display: flex; gap: 12px; margin-bottom: 32px; flex-wrap: wrap; }

.hero__proof {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.avatars { display: flex; }
.avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 0.75rem;
    font-weight: 700;
    border: 2px solid #fff;
    margin-left: -8px;
}
.avatar:first-child { margin-left: 0; }

/* Hero Mockup */
.hero__visual { position: relative; }

.hero__mockup {
    background: var(--color-bg-dark);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    transform: perspective(1200px) rotateY(-8deg) rotateX(4deg);
    transition: transform 0.4s ease;
}
.hero__mockup:hover { transform: perspective(1200px) rotateY(-2deg) rotateX(1deg); }

.mockup__bar {
    display: flex;
    gap: 6px;
    padding: 12px 16px;
    background: #1a1a2e;
}
.dot { width: 10px; height: 10px; border-radius: 50%; }
.dot--red { background: #ff5f57; }
.dot--yellow { background: #ffbd2e; }
.dot--green { background: #28c840; }

.mockup__body {
    display: flex;
    padding: 16px;
    gap: 12px;
    min-height: 280px;
}
.mockup__sidebar {
    width: 48px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.mockup__item {
    height: 8px;
    background: #2a2a3e;
    border-radius: 4px;
}
.mockup__item.active { background: var(--color-primary); }
.mockup__main { flex: 1; display: flex; gap: 12px; }
.mockup__col { flex: 1; display: flex; flex-direction: column; gap: 8px; }
.mockup__card {
    border-radius: 6px;
    animation: pulse-card 3s ease-in-out infinite;
}
.c1 { height: 60px; background: rgba(108,92,231,0.3); }
.c2 { height: 80px; background: rgba(108,92,231,0.15); animation-delay: 0.5s; }
.c3 { height: 50px; background: rgba(0,184,148,0.3); animation-delay: 1s; }
.c4 { height: 40px; background: rgba(0,184,148,0.15); animation-delay: 1.5s; }
.c5 { height: 55px; background: rgba(225,112,85,0.25); animation-delay: 2s; }
.c6 { height: 70px; background: rgba(9,132,227,0.25); animation-delay: 0.8s; }

@keyframes pulse-card {
    0%, 100% { opacity: 0.7; }
    50% { opacity: 1; }
}

/* --- Trust Strip --- */
.trust-strip {
    padding: 40px 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg);
}
.trust-strip .container { text-align: center; }
.trust-strip__label {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-bottom: 20px;
}
.trust-strip__logos {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 48px;
    flex-wrap: wrap;
}
.trust-logo {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--color-text-muted);
    opacity: 0.5;
    letter-spacing: -0.02em;
    transition: opacity var(--transition);
}
.trust-logo:hover { opacity: 0.8; }

/* --- Sections --- */
.section { padding: 96px 0; }
.section--alt { background: var(--color-bg-alt); }

.section__header { text-align: center; max-width: 640px; margin: 0 auto 64px; }
.section__tag {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 12px;
}
.section__title { margin-bottom: 16px; }
.section__subtitle {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

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

.feature-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 32px;
    transition: all var(--transition);
}
.feature-card:hover {
    border-color: var(--color-primary-light);
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
}

.feature-card__icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(108, 92, 231, 0.08);
    color: var(--color-primary);
    border-radius: var(--radius-sm);
    margin-bottom: 20px;
}

.feature-card__title { margin-bottom: 8px; font-weight: 700; }
.feature-card__desc { color: var(--color-text-secondary); font-size: 0.95rem; line-height: 1.6; }

/* --- About --- */
.about__content { max-width: 680px; }
.about__content p {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}

.stats-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-top: 40px;
    padding-top: 40px;
    border-top: 1px solid var(--color-border);
}

.stat__number {
    display: block;
    font-size: 2rem;
    font-weight: 800;
    color: var(--color-primary);
    letter-spacing: -0.02em;
}
.stat__label {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

/* --- Pricing --- */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    align-items: start;
}

.plan {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 36px 32px;
    position: relative;
    transition: all var(--transition);
}
.plan:hover { box-shadow: var(--shadow-md); }

.plan--popular {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-lg);
    transform: scale(1.02);
}

.plan__badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-primary);
    color: #fff;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 4px 16px;
    border-radius: 100px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.plan__name { font-size: 1.3rem; font-weight: 700; }
.plan__desc { font-size: 0.9rem; color: var(--color-text-muted); margin-top: 4px; }
.plan__header { margin-bottom: 24px; }

.plan__price {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 24px;
}
.plan__currency { font-size: 1.5rem; vertical-align: super; font-weight: 600; }
.plan__period { font-size: 0.95rem; font-weight: 400; color: var(--color-text-muted); }

.plan__features { margin-bottom: 32px; }
.plan__features li {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 0;
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    border-bottom: 1px solid var(--color-border);
}
.plan__features li:last-child { border-bottom: none; }
.plan__features svg { flex-shrink: 0; }

/* --- Testimonials --- */
.testimonial-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.testimonial {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 32px;
    transition: all var(--transition);
}
.testimonial:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }

.testimonial__stars {
    color: #F9A825;
    font-size: 1rem;
    margin-bottom: 16px;
    letter-spacing: 2px;
}

.testimonial__text {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--color-text);
    margin-bottom: 20px;
}

.testimonial__author {
    display: flex;
    align-items: center;
    gap: 12px;
}
.testimonial__author strong { display: block; font-size: 0.95rem; }
.testimonial__author span { font-size: 0.8rem; color: var(--color-text-muted); }

/* --- FAQ --- */
.faq-list { max-width: 720px; margin: 0 auto; }

.faq-item {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    margin-bottom: 12px;
    overflow: hidden;
    transition: all var(--transition);
}
.faq-item[open] { border-color: var(--color-primary-light); }

.faq-item__q {
    padding: 20px 24px;
    font-size: 1.05rem;
    font-weight: 600;
    cursor: pointer;
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: background var(--transition);
}
.faq-item__q:hover { background: var(--color-bg-alt); }
.faq-item__q::-webkit-details-marker { display: none; }
.faq-item__q::after {
    content: '+';
    font-size: 1.4rem;
    font-weight: 300;
    color: var(--color-text-muted);
    transition: transform var(--transition);
}
.faq-item[open] .faq-item__q::after { content: '−'; }

.faq-item__a {
    padding: 0 24px 20px;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* --- CTA Section --- */
.cta-section {
    background: linear-gradient(135deg, var(--color-primary) 0%, #4834D4 50%, #341f97 100%);
    padding: 96px 0;
    text-align: center;
}
.cta-section__inner { max-width: 640px; margin: 0 auto; }
.cta-section__title { color: #fff; margin-bottom: 16px; }
.cta-section__desc { color: rgba(255,255,255,0.8); font-size: 1.15rem; line-height: 1.7; margin-bottom: 32px; }
.cta-section__actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* --- Footer --- */
.footer {
    background: var(--color-bg-dark);
    color: rgba(255,255,255,0.7);
    padding: 64px 0 0;
}

.footer__inner {
    display: grid;
    grid-template-columns: 1.5fr 3fr;
    gap: 64px;
    padding-bottom: 48px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer .logo { color: #fff; }
.footer__brand p { margin-top: 12px; font-size: 0.9rem; color: rgba(255,255,255,0.5); }

.footer__links { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.footer__col h4 { color: #fff; font-size: 0.85rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 16px; }
.footer__col a { display: block; font-size: 0.9rem; padding: 4px 0; color: rgba(255,255,255,0.5); transition: color var(--transition); }
.footer__col a:hover { color: #fff; }

.footer__bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 0;
    font-size: 0.8rem;
    color: rgba(255,255,255,0.35);
}
.footer__legal { display: flex; gap: 24px; }
.footer__legal a { color: rgba(255,255,255,0.35); transition: color var(--transition); }
.footer__legal a:hover { color: rgba(255,255,255,0.7); }

/* --- Animations --- */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}
.fade-in:nth-child(2) { transition-delay: 0.1s; }
.fade-in:nth-child(3) { transition-delay: 0.2s; }
.fade-in:nth-child(4) { transition-delay: 0.3s; }
.fade-in:nth-child(5) { transition-delay: 0.4s; }
.fade-in:nth-child(6) { transition-delay: 0.5s; }

/* --- Responsive --- */
@media (max-width: 1024px) {
    .hero__inner { grid-template-columns: 1fr; gap: 48px; }
    .hero__mockup { transform: perspective(1200px) rotateY(0) rotateX(2deg); }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .pricing-grid { grid-template-columns: repeat(2, 1fr); }
    .pricing-grid .plan:last-child { grid-column: 1 / -1; max-width: 400px; margin: 0 auto; }
    .testimonial-grid { grid-template-columns: 1fr; }
    .stats-row { grid-template-columns: repeat(2, 1fr); }
    .footer__inner { grid-template-columns: 1fr; gap: 40px; }
}

@media (max-width: 768px) {
    .nav-links, .nav-actions { display: none; }
    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: #fff;
        border-bottom: 1px solid var(--color-border);
        padding: 24px;
        gap: 16px;
        box-shadow: var(--shadow-md);
    }
    .nav-actions.open {
        display: flex;
        position: absolute;
        top: calc(64px + var(--nav-links-height, 200px));
        left: 0;
        right: 0;
        background: #fff;
        padding: 0 24px 24px;
        border-bottom: 1px solid var(--color-border);
    }
    .mobile-toggle { display: flex; }

    .hero { padding: 100px 0 60px; }
    .hero__subtitle { font-size: 1.05rem; }

    .section { padding: 64px 0; }
    .section__header { margin-bottom: 40px; }
    .features-grid { grid-template-columns: 1fr; }
    .pricing-grid { grid-template-columns: 1fr; }
    .pricing-grid .plan:last-child { max-width: none; }
    .plan--popular { transform: none; }
    .stats-row { grid-template-columns: repeat(2, 1fr); gap: 16px; }
    .footer__links { grid-template-columns: repeat(2, 1fr); }
    .footer__bottom { flex-direction: column; gap: 12px; text-align: center; }
    .trust-strip__logos { gap: 24px; }
}

@media (max-width: 480px) {
    .container { padding: 0 16px; }
    .hero__cta { flex-direction: column; }
    .hero__cta .btn { width: 100%; justify-content: center; }
    .cta-section__actions { flex-direction: column; align-items: center; }
    .stats-row { grid-template-columns: 1fr 1fr; }
    .footer__links { grid-template-columns: 1fr; }
}