/* =========================================================
   AI ECOMMERCE — STAGE A
   Main stylesheet
   ========================================================= */


/* =========================================================
   VARIABLES
   ========================================================= */

:root {

    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-primary-dark: #172554;

    --color-text: #172033;
    --color-text-light: #64748b;

    --color-background: #ffffff;
    --color-background-alt: #f1f5f9;
    --color-background-blue: #eff6ff;

    --color-border: #dbe3ee;

    --color-success: #059669;
    --color-danger: #dc2626;

    --max-width: 1180px;

    --radius-small: 8px;
    --radius-medium: 12px;
    --radius-large: 18px;

    --shadow-small:
        0 2px 8px rgba(15, 23, 42, 0.05);

    --shadow-medium:
        0 12px 35px rgba(15, 23, 42, 0.10);

    --transition: 0.2s ease;
}


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

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

html {
    scroll-behavior: smooth;
}

body {

    margin: 0;

    font-family:
        Inter,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        Roboto,
        Helvetica,
        Arial,
        sans-serif;

    color: var(--color-text);

    background: var(--color-background);

    line-height: 1.6;
}

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

button,
input,
select {
    font: inherit;
}

button {
    cursor: pointer;
}

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

p {
    margin-top: 0;
}

h1,
h2,
h3,
h4 {
    line-height: 1.2;
}


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

.container {

    width:
        min(
            calc(100% - 40px),
            var(--max-width)
        );

    margin-left: auto;
    margin-right: auto;
}


/* =========================================================
   HEADER
   ========================================================= */

.site-header {

    position: sticky;

    top: 0;

    z-index: 100;

    background:
        rgba(255, 255, 255, 0.97);

    backdrop-filter:
        blur(10px);

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

.header-inner {

    min-height: 72px;

    display: flex;

    align-items: center;

    justify-content: space-between;

    gap: 30px;
}

.logo {

    color:
        var(--color-primary-dark);

    font-size: 1.25rem;

    font-weight: 800;

    letter-spacing: -0.03em;
}

.main-nav {

    display: flex;

    align-items: center;

    gap: 28px;

    font-size: 0.95rem;

    font-weight: 600;
}

.main-nav a {

    position: relative;

    transition:
        color var(--transition);
}

.main-nav a:hover {

    color:
        var(--color-primary);
}


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

.hero {

    background:
        linear-gradient(
            135deg,
            #eff6ff 0%,
            #ffffff 55%,
            #eef2ff 100%
        );

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

.hero-content {

    max-width: 850px;

    padding-top: 110px;

    padding-bottom: 120px;
}

.eyebrow {

    margin-bottom: 14px;

    color:
        var(--color-primary);

    font-size: 0.78rem;

    font-weight: 800;

    text-transform: uppercase;

    letter-spacing: 0.14em;
}

.hero h1 {

    max-width: 780px;

    margin:
        0 0 24px;

    color:
        var(--color-primary-dark);

    font-size:
        clamp(
            2.8rem,
            7vw,
            5rem
        );

    font-weight: 800;

    letter-spacing: -0.055em;
}

.hero-text {

    max-width: 680px;

    margin-bottom: 34px;

    color:
        var(--color-text-light);

    font-size: 1.2rem;
}


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

.button {

    display: inline-flex;

    align-items: center;

    justify-content: center;

    gap: 8px;

    border: none;

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

    padding:
        12px 20px;

    color: #ffffff;

    background:
        var(--color-primary);

    font-weight: 700;

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

.button:hover {

    background:
        var(--color-primary-hover);

    transform:
        translateY(-1px);

    box-shadow:
        0 6px 16px rgba(37, 99, 235, 0.25);
}

.button:active {

    transform:
        translateY(0);
}

.button-large {

    min-height: 50px;

    padding:
        14px 26px;
}


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

.section {

    padding:
        80px 0;
}

.section-alt {

    background:
        var(--color-background-blue);
}

.section-heading {

    max-width: 700px;

    margin-bottom: 40px;
}

.section-heading h2 {

    margin:
        0 0 10px;

    color:
        var(--color-primary-dark);

    font-size:
        clamp(
            2rem,
            4vw,
            2.8rem
        );

    letter-spacing:
        -0.035em;
}

.section-heading p {

    color:
        var(--color-text-light);
}


/* =========================================================
   PRODUCT GRID
   ========================================================= */

.product-grid {

    display: grid;

    grid-template-columns:
        repeat(
            4,
            minmax(0, 1fr)
        );

    gap: 24px;
}


/* =========================================================
   PRODUCT CARD
   ========================================================= */

.product-card {

    overflow: hidden;

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

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

    background:
        var(--color-background);

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

.product-card:hover {

    transform:
        translateY(-4px);

    border-color:
        #bfdbfe;

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

.product-card > a {
    display: block;
}

.product-card img {

    width: 100%;

    aspect-ratio: 1 / 1;

    object-fit: cover;

    background:
        var(--color-background-alt);
}

.product-card-content {
    padding: 20px;
}

.product-category {

    margin-bottom: 7px;

    color:
        var(--color-primary);

    font-size: 0.75rem;

    font-weight: 800;

    text-transform: uppercase;

    letter-spacing: 0.1em;
}

.product-card h3 {

    margin:
        0 0 10px;

    font-size: 1.05rem;
}

.product-card h3 a:hover {

    color:
        var(--color-primary);
}

.product-description {

    min-height: 52px;

    margin-bottom: 18px;

    color:
        var(--color-text-light);

    font-size: 0.9rem;
}

.product-card-footer {

    display: flex;

    align-items: center;

    justify-content: space-between;

    gap: 12px;
}

.price {

    color:
        var(--color-primary-dark);

    font-size: 1.05rem;

    font-weight: 800;
}


/* =========================================================
   PAGE HEADER
   ========================================================= */

.page-header {

    padding:
        70px 0;

    background:
        linear-gradient(
            135deg,
            #eff6ff,
            #ffffff
        );

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

.page-header h1 {

    margin:
        0 0 10px;

    color:
        var(--color-primary-dark);

    font-size:
        clamp(
            2.3rem,
            5vw,
            4rem
        );

    letter-spacing:
        -0.04em;
}

.page-header p:last-child {

    margin: 0;

    color:
        var(--color-text-light);
}


/* =========================================================
   PRODUCT DETAIL
   ========================================================= */

.product-detail {

    display: grid;

    grid-template-columns:
        minmax(0, 1.1fr)
        minmax(320px, 0.9fr);

    gap: 70px;

    align-items:
        start;
}

.product-detail-image img {

    width: 100%;

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

    background:
        var(--color-background-alt);
}

.product-detail-content {

    position: sticky;

    top: 110px;
}

.product-detail-content h1 {

    margin:
        0 0 18px;

    color:
        var(--color-primary-dark);

    font-size:
        clamp(
            2.2rem,
            5vw,
            3.6rem
        );

    letter-spacing:
        -0.045em;
}

.product-detail-price {

    margin-bottom: 24px;

    color:
        var(--color-primary);

    font-size: 1.5rem;

    font-weight: 800;
}

.product-detail-content > p:not(
    .product-category
):not(
    .product-detail-price
) {

    color:
        var(--color-text-light);
}

.purchase-controls {

    margin-top: 32px;
}

.purchase-controls label {

    display: block;

    margin-bottom: 8px;

    font-weight: 700;
}

.purchase-controls input {

    width: 100%;

    max-width: 130px;

    height: 48px;

    margin-bottom: 14px;

    padding:
        10px 12px;

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

    border-radius:
        var(--radius-small);
}

.purchase-controls input:focus {

    outline: none;

    border-color:
        var(--color-primary);

    box-shadow:
        0 0 0 3px rgba(37, 99, 235, 0.12);
}

.purchase-controls .button {
    width: 100%;
}


/* =========================================================
   CART
   ========================================================= */

.cart-list {

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

.cart-item {

    display: grid;

    grid-template-columns:
        100px
        minmax(0, 1fr)
        100px
        auto
        auto;

    align-items: center;

    gap: 20px;

    padding:
        20px 0;

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

.cart-item img {

    width: 100px;

    height: 100px;

    object-fit: cover;

    border-radius:
        var(--radius-small);
}

.cart-item-details h3 {

    margin:
        0 0 6px;

    font-size: 1rem;
}

.cart-item-details p {

    margin: 0;

    color:
        var(--color-text-light);
}

.cart-quantity input {

    width: 75px;

    height: 42px;

    padding:
        8px 10px;

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

    border-radius:
        var(--radius-small);
}

.cart-quantity input:focus {

    outline: none;

    border-color:
        var(--color-primary);

    box-shadow:
        0 0 0 3px rgba(37, 99, 235, 0.12);
}

.remove-button {

    border: none;

    background: transparent;

    color:
        var(--color-danger);

    font-weight: 650;
}

.remove-button:hover {

    text-decoration:
        underline;
}

.cart-summary {

    display: flex;

    align-items: center;

    justify-content: flex-end;

    gap: 30px;

    margin-top: 30px;

    padding-top: 25px;

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

.cart-summary h2 {

    margin: 0;

    color:
        var(--color-primary-dark);

    font-size: 1.3rem;
}


/* =========================================================
   EMPTY STATES
   ========================================================= */

.empty-state {

    padding:
        80px 20px;

    text-align: center;
}

.empty-state h1 {

    margin-bottom:
        12px;

    color:
        var(--color-primary-dark);
}

.empty-state p {

    margin-bottom:
        25px;

    color:
        var(--color-text-light);
}


/* =========================================================
   FEATURE GRID
   ========================================================= */

.feature-grid {

    display: grid;

    grid-template-columns:
        repeat(
            3,
            1fr
        );

    gap: 30px;
}

.feature {

    padding:
        30px;

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

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

    background:
        var(--color-background);

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

.feature:hover {

    transform:
        translateY(-3px);

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

.feature h3 {

    margin-top: 0;

    margin-bottom: 10px;

    color:
        var(--color-primary-dark);
}

.feature p {

    margin: 0;

    color:
        var(--color-text-light);
}


/* =========================================================
   NOTIFICATION
   ========================================================= */

.notification {

    position: fixed;

    right: 20px;

    bottom: 20px;

    z-index: 1000;

    max-width: 350px;

    padding:
        14px 20px;

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

    color: #ffffff;

    background:
        var(--color-primary-dark);

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

    animation:
        notification-in 0.2s ease;
}

@keyframes notification-in {

    from {

        opacity: 0;

        transform:
            translateY(10px);

    }

    to {

        opacity: 1;

        transform:
            translateY(0);

    }
}


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

.site-footer {

    margin-top:
        80px;

    padding:
        50px 0 25px;

    color:
        var(--color-text-light);

    background:
        #f1f5f9;
}

.footer-inner {

    display: flex;

    justify-content: space-between;

    gap: 40px;
}

.footer-inner p {

    margin:
        8px 0 0;
}

.footer-links {

    display: flex;

    gap: 25px;
}

.footer-links a:hover {

    color:
        var(--color-primary);

    text-decoration:
        underline;
}

.footer-bottom {

    margin-top:
        40px;

    padding-top:
        20px;

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

    font-size:
        0.85rem;
}


/* =========================================================
   RESPONSIVE — TABLET
   ========================================================= */

@media (max-width: 950px) {

    .product-grid {

        grid-template-columns:
            repeat(
                2,
                minmax(0, 1fr)
            );
    }

    .product-detail {

        grid-template-columns:
            1fr;

        gap: 40px;
    }

    .product-detail-content {

        position: static;
    }

    .feature-grid {

        grid-template-columns:
            1fr;
    }

}


/* =========================================================
   RESPONSIVE — MOBILE
   ========================================================= */

@media (max-width: 600px) {

    .container {

        width:
            min(
                calc(100% - 24px),
                var(--max-width)
            );
    }

    .header-inner {

        min-height:
            64px;
    }

    .main-nav {

        gap:
            12px;

        font-size:
            0.85rem;
    }

    .hero-content {

        padding-top:
            70px;

        padding-bottom:
            80px;
    }

    .hero h1 {

        font-size:
            2.7rem;
    }

    .hero-text {

        font-size:
            1rem;
    }

    .section {

        padding:
            60px 0;
    }

    .product-grid {

        grid-template-columns:
            1fr;
    }

    .product-card-footer {

        align-items:
            flex-end;
    }

    .cart-item {

        grid-template-columns:
            80px
            1fr;

        gap:
            15px;
    }

    .cart-item img {

        width:
            80px;

        height:
            80px;
    }

    .cart-quantity,
    .cart-item > strong,
    .remove-button {

        grid-column:
            2;
    }

    .cart-summary {

        flex-direction:
            column;

        align-items:
            stretch;
    }

    .cart-summary .button {

        width:
            100%;
    }

    .footer-inner {

        flex-direction:
            column;
    }

}