/* =========================================================
   KHANHTECH
   Modern Dark / Light UI
   ========================================================= */

:root {
    --bg: #050505;
    --bg-secondary: #0b0b0d;
    --surface: #111114;
    --surface-hover: #18181c;

    --text: #ffffff;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;

    --border: rgba(255, 255, 255, 0.10);
    --border-strong: rgba(255, 255, 255, 0.18);

    --accent: #6d5dfc;
    --accent-2: #00c6ff;

    --gradient:
        linear-gradient(
            135deg,
            #6d5dfc 0%,
            #00c6ff 100%
        );

    --shadow:
        0 20px 60px rgba(0, 0, 0, 0.35);

    --radius-sm: 10px;
    --radius-md: 16px;
    --radius-lg: 24px;

    --container: 1200px;

    --transition:
        0.25s ease;
}


/* =========================================================
   LIGHT MODE
   ========================================================= */

body.light {
    --bg: #f7f7f8;
    --bg-secondary: #ffffff;
    --surface: #ffffff;
    --surface-hover: #f1f1f3;

    --text: #111113;
    --text-secondary: #52525b;
    --text-muted: #71717a;

    --border: rgba(0, 0, 0, 0.08);
    --border-strong: rgba(0, 0, 0, 0.15);

    --shadow:
        0 20px 60px rgba(0, 0, 0, 0.10);
}


/* =========================================================
   RESET
   ========================================================= */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family:
        Inter,
        ui-sans-serif,
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;

    background:
        radial-gradient(
            circle at 50% -10%,
            rgba(109, 93, 252, 0.14),
            transparent 35%
        ),
        var(--bg);

    color: var(--text);

    line-height: 1.6;

    min-height: 100vh;

    transition:
        background var(--transition),
        color var(--transition);
}

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

button,
a {
    -webkit-tap-highlight-color: transparent;
}

img {
    max-width: 100%;
    display: block;
}

::selection {
    background: var(--accent);
    color: white;
}


/* =========================================================
   SCROLLBAR
   ========================================================= */

::-webkit-scrollbar {
    width: 9px;
}

::-webkit-scrollbar-track {
    background: var(--bg);
}

::-webkit-scrollbar-thumb {
    background: #303038;
    border-radius: 999px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent);
}


/* =========================================================
   CONTAINER
   ========================================================= */

.nav-container,
.section,
.footer-container,
.footer-bottom {
    width: min(
        calc(100% - 40px),
        var(--container)
    );

    margin-inline: auto;
}


/* =========================================================
   NAVBAR
   ========================================================= */

.navbar {
    position: fixed;

    top: 0;
    left: 0;

    width: 100%;

    z-index: 1000;

    background:
        rgba(5, 5, 5, 0.70);

    backdrop-filter:
        blur(18px);

    -webkit-backdrop-filter:
        blur(18px);

    border-bottom:
        1px solid var(--border);
}

body.light .navbar {
    background:
        rgba(255, 255, 255, 0.78);
}

.nav-container {
    height: 76px;

    display: flex;

    align-items: center;

    justify-content: space-between;

    gap: 30px;
}

.logo {
    font-size: 18px;

    font-weight: 800;

    letter-spacing: -0.5px;

    background:
        var(--gradient);

    -webkit-background-clip: text;
    background-clip: text;

    color: transparent;
}

.nav-menu {
    display: flex;

    align-items: center;

    gap: 28px;

    margin-left: auto;
}

.nav-menu a {
    font-size: 14px;

    color: var(--text-secondary);

    transition:
        color var(--transition);
}

.nav-menu a:hover {
    color: var(--text);
}

.nav-actions {
    display: flex;

    align-items: center;

    gap: 10px;
}


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

.btn {
    display: inline-flex;

    align-items: center;
    justify-content: center;

    min-height: 44px;

    padding:
        0 18px;

    border-radius:
        12px;

    font-size: 14px;

    font-weight: 600;

    border:
        1px solid transparent;

    cursor: pointer;

    transition:
        transform var(--transition),
        background var(--transition),
        border var(--transition),
        box-shadow var(--transition);
}

.btn:hover {
    transform:
        translateY(-2px);
}

.btn-primary {
    color: white;

    background:
        var(--gradient);

    box-shadow:
        0 10px 30px
        rgba(109, 93, 252, 0.20);
}

.btn-primary:hover {
    box-shadow:
        0 15px 40px
        rgba(109, 93, 252, 0.35);
}

.btn-secondary {
    background:
        var(--surface);

    border:
        1px solid var(--border-strong);

    color:
        var(--text);
}

.btn-secondary:hover {
    background:
        var(--surface-hover);

    border-color:
        rgba(109, 93, 252, 0.4);
}


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

.hero {
    width: min(
        calc(100% - 40px),
        var(--container)
    );

    margin:
        0 auto;

    min-height:
        850px;

    padding-top:
        150px;

    padding-bottom:
        100px;

    display:
        grid;

    grid-template-columns:
        1fr 1fr;

    align-items:
        center;

    gap:
        70px;
}

.hero-content {
    animation:
        heroEnter 0.8s ease both;
}

.hero-badge {
    display:
        inline-flex;

    padding:
        7px 12px;

    border-radius:
        999px;

    font-size:
        11px;

    font-weight:
        700;

    letter-spacing:
        1.5px;

    color:
        #ffffff;

    background:
        rgba(109, 93, 252, 0.12);

    border:
        1px solid
        rgba(109, 93, 252, 0.25);

    margin-bottom:
        22px;
}

.hero h1 {
    font-size:
        clamp(52px, 7vw, 92px);

    line-height:
        0.98;

    letter-spacing:
        -5px;

    max-width:
        800px;
}

.hero h1 span {
    display:
        block;

    background:
        var(--gradient);

    -webkit-background-clip:
        text;

    background-clip:
        text;

    color:
        transparent;
}

.hero p {
    margin-top:
        28px;

    max-width:
        570px;

    color:
        var(--text-secondary);

    font-size:
        18px;
}

.hero-buttons {
    display:
        flex;

    gap:
        12px;

    margin-top:
        34px;

    flex-wrap:
        wrap;
}


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

.hero-preview {
    position:
        relative;

    animation:
        previewEnter 1s ease 0.15s both;
}

.os-window {
    position:
        relative;

    width:
        100%;

    min-height:
        430px;

    border-radius:
        22px;

    overflow:
        hidden;

    background:
        linear-gradient(
            145deg,
            #17171c,
            #08080a
        );

    border:
        1px solid
        rgba(255,255,255,0.13);

    box-shadow:
        0 40px 100px
        rgba(0,0,0,0.45);

    transform:
        perspective(1200px)
        rotateY(-4deg)
        rotateX(2deg);

    transition:
        transform 0.5s ease;
}

.os-window:hover {
    transform:
        perspective(1200px)
        rotateY(0)
        rotateX(0)
        translateY(-6px);
}

.window-top {
    height:
        42px;

    display:
        flex;

    align-items:
        center;

    gap:
        7px;

    padding:
        0 16px;

    border-bottom:
        1px solid
        rgba(255,255,255,0.08);
}

.window-top span {
    width:
        10px;

    height:
        10px;

    border-radius:
        50%;

    background:
        #555;
}

.window-content {
    display:
        flex;

    height:
        388px;
}

.fake-sidebar {
    width:
        80px;

    background:
        rgba(255,255,255,0.03);

    border-right:
        1px solid
        rgba(255,255,255,0.06);
}

.fake-desktop {
    flex:
        1;

    padding:
        30px;

    display:
        grid;

    grid-template-columns:
        repeat(2, 1fr);

    gap:
        20px;

    align-content:
        center;
}

.fake-card {
    height:
        120px;

    border-radius:
        16px;

    background:
        linear-gradient(
            135deg,
            rgba(109,93,252,0.22),
            rgba(0,198,255,0.08)
        );

    border:
        1px solid
        rgba(255,255,255,0.08);
}


/* =========================================================
   SECTION
   ========================================================= */

.section {
    padding:
        120px 0;
}

.section-header {
    max-width:
        720px;

    margin-bottom:
        55px;
}

.section-label {
    display:
        block;

    color:
        #8b7fff;

    font-size:
        12px;

    font-weight:
        800;

    letter-spacing:
        2px;

    margin-bottom:
        14px;
}

.section-header h2 {
    font-size:
        clamp(36px, 5vw, 60px);

    line-height:
        1.05;

    letter-spacing:
        -3px;
}

.section-header h2 span {
    background:
        var(--gradient);

    -webkit-background-clip:
        text;

    background-clip:
        text;

    color:
        transparent;
}

.section-header p {
    color:
        var(--text-secondary);

    margin-top:
        18px;

    font-size:
        17px;
}


/* =========================================================
   PRODUCTS
   ========================================================= */

.product-grid {
    display:
        grid;

    grid-template-columns:
        repeat(4, 1fr);

    gap:
        18px;
}

.product-card {
    padding:
        28px;

    min-height:
        280px;

    background:
        linear-gradient(
            145deg,
            var(--surface),
            var(--bg-secondary)
        );

    border:
        1px solid
        var(--border);

    border-radius:
        var(--radius-lg);

    transition:
        transform 0.3s ease,
        border-color 0.3s ease,
        background 0.3s ease;

    position:
        relative;

    overflow:
        hidden;
}

.product-card::before {
    content:
        "";

    position:
        absolute;

    width:
        180px;

    height:
        180px;

    top:
        -100px;

    right:
        -100px;

    background:
        rgba(109,93,252,0.15);

    filter:
        blur(50px);

    border-radius:
        50%;
}

.product-card:hover {
    transform:
        translateY(-7px);

    border-color:
        rgba(109,93,252,0.45);

    background:
        var(--surface-hover);
}

.product-icon {
    width:
        46px;

    height:
        46px;

    display:
        flex;

    align-items:
        center;

    justify-content:
        center;

    border-radius:
        13px;

    background:
        var(--gradient);

    color:
        white;

    font-weight:
        800;

    font-size:
        13px;

    margin-bottom:
        28px;
}

.product-card h3 {
    font-size:
        22px;

    margin-bottom:
        10px;
}

.product-card p {
    color:
        var(--text-secondary);

    font-size:
        14px;

    margin-bottom:
        25px;
}

.product-card a {
    font-size:
        14px;

    font-weight:
        600;

    color:
        #9b91ff;
}


/* =========================================================
   KHANHOS
   ========================================================= */

.khanhos-section {
    max-width:
        var(--container);
}

.khanhos-preview {
    padding:
        20px;

    border-radius:
        28px;

    background:
        linear-gradient(
            145deg,
            rgba(109,93,252,0.15),
            rgba(0,198,255,0.05)
        );

    border:
        1px solid
        var(--border);
}

.os-placeholder {
    min-height:
        500px;

    border-radius:
        20px;

    display:
        flex;

    flex-direction:
        column;

    justify-content:
        center;

    align-items:
        center;

    background:
        linear-gradient(
            145deg,
            #17171d,
            #070709
        );

    border:
        1px solid
        rgba(255,255,255,0.08);

    box-shadow:
        var(--shadow);
}

.placeholder-title {
    font-size:
        clamp(50px, 8vw, 100px);

    font-weight:
        900;

    letter-spacing:
        -6px;

    background:
        var(--gradient);

    -webkit-background-clip:
        text;

    background-clip:
        text;

    color:
        transparent;
}

.placeholder-text {
    color:
        #777;

    margin-top:
        8px;
}

.center-button {
    display:
        flex;

    justify-content:
        center;

    margin-top:
        35px;
}


/* =========================================================
   FEATURES
   ========================================================= */

.features-grid {
    display:
        grid;

    grid-template-columns:
        repeat(4, 1fr);

    gap:
        18px;
}

.feature {
    padding:
        30px;

    border-top:
        1px solid
        var(--border);
}

.feature-icon {
    font-size:
        30px;

    margin-bottom:
        22px;
}

.feature h3 {
    font-size:
        19px;

    margin-bottom:
        9px;
}

.feature p {
    color:
        var(--text-secondary);

    font-size:
        14px;
}


/* =========================================================
   ROADMAP
   ========================================================= */

.roadmap {
    position:
        relative;

    display:
        grid;

    grid-template-columns:
        repeat(4, 1fr);

    gap:
        25px;
}

.roadmap::before {
    content:
        "";

    position:
        absolute;

    left:
        0;

    right:
        0;

    top:
        17px;

    height:
        1px;

    background:
        var(--border);

    z-index:
        0;
}

.roadmap-item {
    position:
        relative;

    z-index:
        1;

    padding-top:
        45px;
}

.roadmap-item::before {
    content:
        "";

    position:
        absolute;

    top:
        10px;

    left:
        0;

    width:
        15px;

    height:
        15px;

    border-radius:
        50%;

    background:
        var(--bg);

    border:
        2px solid
        #555;
}

.roadmap-item.active::before {
    background:
        var(--accent);

    border-color:
        var(--accent);

    box-shadow:
        0 0 20px
        rgba(109,93,252,0.6);
}

.roadmap-year {
    font-size:
        12px;

    color:
        #8b7fff;

    font-weight:
        800;
}

.roadmap-item h3 {
    margin-top:
        8px;

    font-size:
        18px;
}

.roadmap-item p {
    margin-top:
        8px;

    color:
        var(--text-secondary);

    font-size:
        14px;
}


/* =========================================================
   DEVELOPER SECTION
   ========================================================= */

.developer-section {
    border:
        1px solid
        var(--border);

    border-radius:
        var(--radius-lg);

    padding:
        80px;

    background:
        radial-gradient(
            circle at 80% 20%,
            rgba(109,93,252,0.18),
            transparent 35%
        ),
        var(--surface);
}

.developer-content {
    max-width:
        650px;
}

.developer-content h2 {
    font-size:
        clamp(36px, 5vw, 60px);

    line-height:
        1;

    letter-spacing:
        -3px;
}

.developer-content p {
    color:
        var(--text-secondary);

    margin:
        20px 0 30px;
}


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

.support-section {
    text-align:
        center;
}

.support-section .section-header {
    margin-inline:
        auto;
}


/* =========================================================
   CTA
   ========================================================= */

.cta {
    width:
        min(
            calc(100% - 40px),
            var(--container)
        );

    margin:
        50px auto 120px;

    padding:
        100px 30px;

    text-align:
        center;

    border-radius:
        30px;

    background:
        radial-gradient(
            circle at 50% 0%,
            rgba(109,93,252,0.30),
            transparent 55%
        ),
        var(--surface);

    border:
        1px solid
        var(--border);
}

.cta h2 {
    font-size:
        clamp(40px, 6vw, 70px);

    letter-spacing:
        -4px;
}

.cta p {
    color:
        var(--text-secondary);

    margin:
        15px 0 30px;
}


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

.footer {
    border-top:
        1px solid
        var(--border);

    background:
        var(--bg-secondary);

    padding-top:
        70px;
}

.footer-container {
    display:
        grid;

    grid-template-columns:
        2fr 1fr 1fr 1fr;

    gap:
        50px;

    padding-bottom:
        60px;
}

.footer-brand p {
    color:
        var(--text-muted);

    font-size:
        13px;

    margin-top:
        10px;
}

.footer-column {
    display:
        flex;

    flex-direction:
        column;

    gap:
        10px;
}

.footer-column h4 {
    font-size:
        13px;

    margin-bottom:
        8px;
}

.footer-column a {
    color:
        var(--text-muted);

    font-size:
        13px;

    transition:
        color var(--transition);
}

.footer-column a:hover {
    color:
        var(--text);
}

.footer-bottom {
    padding:
        20px 0;

    border-top:
        1px solid
        var(--border);

    display:
        flex;

    justify-content:
        space-between;

    gap:
        20px;

    color:
        var(--text-muted);

    font-size:
        12px;
}

.footer-bottom div {
    display:
        flex;

    gap:
        20px;
}


/* =========================================================
   ANIMATIONS
   ========================================================= */

@keyframes heroEnter {

    from {
        opacity:
            0;

        transform:
            translateY(25px);
    }

    to {
        opacity:
            1;

        transform:
            translateY(0);
    }
}

@keyframes previewEnter {

    from {
        opacity:
            0;

        transform:
            translateY(35px)
            scale(0.97);
    }

    to {
        opacity:
            1;

        transform:
            translateY(0)
            scale(1);
    }
}


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

@media (max-width: 1000px) {

    .nav-menu {
        display:
            none;
    }

    .hero {
        grid-template-columns:
            1fr;

        padding-top:
            130px;

        text-align:
            center;
    }

    .hero-content {
        display:
            flex;

        flex-direction:
            column;

        align-items:
            center;
    }

    .hero p {
        margin-inline:
            auto;
    }

    .hero-preview {
        max-width:
            800px;

        width:
            100%;

        margin-inline:
            auto;
    }

    .product-grid {
        grid-template-columns:
            repeat(2, 1fr);
    }

    .features-grid {
        grid-template-columns:
            repeat(2, 1fr);
    }

    .roadmap {
        grid-template-columns:
            repeat(2, 1fr);

        gap:
            45px;
    }

    .roadmap::before {
        display:
            none;
    }

    .footer-container {
        grid-template-columns:
            repeat(2, 1fr);
    }
}


/* =========================================================
   MOBILE
   ========================================================= */

@media (max-width: 600px) {

    .nav-container {
        width:
            calc(100% - 24px);
    }

    .nav-actions .btn-secondary {
        display:
            none;
    }

    .hero {
        width:
            calc(100% - 24px);

        min-height:
            auto;

        padding-top:
            120px;

        padding-bottom:
            70px;
    }

    .hero h1 {
        font-size:
            48px;

        letter-spacing:
            -3px;
    }

    .hero p {
        font-size:
            16px;
    }

    .hero-buttons {
        width:
            100%;

        flex-direction:
            column;
    }

    .hero-buttons .btn {
        width:
            100%;
    }

    .os-window {
        min-height:
            300px;

        transform:
            none;
    }

    .window-content {
        height:
            260px;
    }

    .section {
        width:
            calc(100% - 24px);

        padding:
            80px 0;
    }

    .section-header h2 {
        font-size:
            40px;

        letter-spacing:
            -2px;
    }

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

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

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

    .developer-section {
        padding:
            50px 25px;
    }

    .placeholder-title {
        font-size:
            55px;

        letter-spacing:
            -3px;
    }

    .os-placeholder {
        min-height:
            300px;
    }

    .cta {
        width:
            calc(100% - 24px);

        padding:
            70px 20px;

        margin-bottom:
            70px;
    }

    .cta h2 {
        font-size:
            42px;

        letter-spacing:
            -2px;
    }

    .footer-container {
        width:
            calc(100% - 24px);

        grid-template-columns:
            1fr 1fr;

        gap:
            40px 20px;
    }

    .footer-bottom {
        width:
            calc(100% - 24px);

        flex-direction:
            column;
    }
}


/* =========================================================
   REDUCED MOTION
   ========================================================= */

@media (prefers-reduced-motion: reduce) {

    html {
        scroll-behavior:
            auto;
    }

    *,
    *::before,
    *::after {
        animation-duration:
            0.01ms !important;

        animation-iteration-count:
            1 !important;

        transition-duration:
            0.01ms !important;
    }
}