/* ============================================================
   HD Workflow – Stylesheet
   ============================================================ */

/* Variables */
:root {
    --c-bg:           #ffffff;
    --c-bg-alt:       #f8fafc;
    --c-dark:         #0f172a;
    --c-dark-mid:     #1e293b;
    --c-text:         #334155;
    --c-muted:        #64748b;
    --c-accent:       #2563eb;
    --c-accent-dark:  #1d4ed8;
    --c-border:       #e2e8f0;
    --c-success:      #16a34a;

    --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, Helvetica, Arial, sans-serif;

    --radius-sm:  4px;
    --radius:     8px;
    --radius-lg:  12px;

    --shadow:    0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.05);

    --ease: 0.2s ease;

    --max-w: 1100px;
}

/* ============================================================
   Reset & Base
   ============================================================ */

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

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

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

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

ul {
    list-style: none;
}

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

/* ============================================================
   Typography
   ============================================================ */

h1, h2, h3 {
    color: var(--c-dark);
    line-height: 1.2;
    font-weight: 700;
    letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 5.5vw, 3.75rem); }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.25rem); }
h3 { font-size: 1.05rem; font-weight: 600; }

/* ============================================================
   Layout utilities
   ============================================================ */

.container {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 5rem 0;
}

.section--alt {
    background: var(--c-bg-alt);
}

.section-head {
    text-align: center;
    margin-bottom: 3rem;
}

.section-head h2 {
    margin-bottom: 0.6rem;
}

.section-head p {
    font-size: 1.05rem;
    color: var(--c-muted);
    max-width: 520px;
    margin: 0 auto;
}

.tag {
    display: inline-block;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--c-accent);
    background: rgba(37,99,235,0.08);
    padding: 0.3rem 0.8rem;
    border-radius: 999px;
    margin-bottom: 0.9rem;
}

/* ============================================================
   Buttons
   ============================================================ */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.6rem;
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: var(--font);
    cursor: pointer;
    border: 2px solid transparent;
    transition: background var(--ease), border-color var(--ease), color var(--ease), box-shadow var(--ease);
    white-space: nowrap;
    line-height: 1;
}

.btn--primary {
    background: var(--c-accent);
    color: #fff;
    border-color: var(--c-accent);
}

.btn--primary:hover {
    background: var(--c-accent-dark);
    border-color: var(--c-accent-dark);
    box-shadow: 0 4px 12px rgba(37,99,235,0.3);
}

.btn--ghost {
    background: transparent;
    color: #fff;
    border-color: rgba(255,255,255,0.35);
}

.btn--ghost:hover {
    background: rgba(255,255,255,0.1);
    border-color: rgba(255,255,255,0.65);
}

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

/* ============================================================
   Header & Navigation
   ============================================================ */

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    transition: background var(--ease), box-shadow var(--ease);
}

.header.scrolled {
    background: rgba(255,255,255,0.96);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: var(--shadow);
}

.header__inner {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 1.5rem;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* Logo */
.logo {
    font-size: 1.15rem;
    font-weight: 700;
    color: #fff;
    letter-spacing: -0.03em;
    transition: color var(--ease);
    flex-shrink: 0;
}

.header.scrolled .logo {
    color: var(--c-dark);
}

/* Desktop nav */
.nav {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav__link {
    font-size: 0.9rem;
    font-weight: 500;
    color: rgba(255,255,255,0.8);
    transition: color var(--ease);
}

.nav__link:hover {
    color: #fff;
}

.header.scrolled .nav__link {
    color: var(--c-text);
}

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

.nav__cta {
    padding: 0.45rem 1.1rem;
    border: 1.5px solid rgba(255,255,255,0.35);
    border-radius: var(--radius);
    color: #fff !important;
    transition: background var(--ease), border-color var(--ease), color var(--ease) !important;
}

.nav__cta:hover {
    background: rgba(255,255,255,0.1);
    border-color: rgba(255,255,255,0.65);
}

.header.scrolled .nav__cta {
    color: var(--c-accent) !important;
    border-color: var(--c-accent);
}

.header.scrolled .nav__cta:hover {
    background: var(--c-accent);
    color: #fff !important;
}

/* Burger button */
.burger {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    width: 40px;
    height: 40px;
}

.burger span {
    display: block;
    width: 22px;
    height: 2px;
    background: #fff;
    border-radius: 2px;
    transition: transform var(--ease), opacity var(--ease), background var(--ease);
}

.header.scrolled .burger span {
    background: var(--c-dark);
}

.burger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.burger.active span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.burger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   Hero
   ============================================================ */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 7rem 1.5rem 5rem;
    background:
        radial-gradient(ellipse at 65% 35%, rgba(37,99,235,0.22) 0%, transparent 55%),
        radial-gradient(ellipse at 15% 80%, rgba(37,99,235,0.10) 0%, transparent 45%),
        linear-gradient(to bottom, #1a1a2e 0%, #1e3a5f 100%);
}

.hero__inner {
    max-width: 720px;
    margin: 0 auto;
    text-align: center;
}

.hero__tag {
    display: inline-block;
    font-size: 0.78rem;
    font-weight: 500;
    letter-spacing: 0.07em;
    text-transform: uppercase;
    color: rgba(255,255,255,0.45);
    margin-bottom: 1.5rem;
}

.hero__title {
    color: #fff;
    margin-bottom: 1.5rem;
    line-height: 1.13;
}

.hero__sub {
    font-size: clamp(0.95rem, 2vw, 1.1rem);
    color: rgba(255,255,255,0.65);
    max-width: 590px;
    margin: 0 auto 2.5rem;
    line-height: 1.75;
}

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

/* ============================================================
   Services
   ============================================================ */

.services__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.card {
    background: var(--c-bg);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-lg);
    padding: 1.75rem 2rem;
    transition: box-shadow var(--ease), transform var(--ease);
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-3px);
}

.card__icon {
    width: 48px;
    height: 48px;
    background: rgba(37,99,235,0.07);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.25rem;
    color: var(--c-accent);
}

.card__icon svg {
    width: 22px;
    height: 22px;
}

.card h3 {
    margin-bottom: 0.7rem;
}

.card p {
    font-size: 0.9rem;
    color: var(--c-muted);
    margin-bottom: 1.25rem;
    line-height: 1.7;
}

.card ul {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.card ul li {
    font-size: 0.85rem;
    color: var(--c-text);
    padding-left: 1.2rem;
    position: relative;
}

.card ul li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--c-accent);
    font-size: 0.8rem;
    top: 0;
}

/* ============================================================
   Case Study
   ============================================================ */

.case__problem {
    background: var(--c-bg);
    border: 1px solid var(--c-border);
    border-left: 4px solid var(--c-accent);
    border-radius: 0 var(--radius) var(--radius) 0;
    padding: 1.25rem 1.75rem;
    margin-bottom: 2rem;
}

.case__problem h3 {
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--c-muted);
    margin-bottom: 0.5rem;
}

.case__problem p {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--c-text);
}

/* Flow diagram */
.flow {
    display: flex;
    align-items: stretch;
    background: var(--c-bg);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-lg);
    padding: 2rem 1rem;
    margin-bottom: 1.5rem;
}

.flow__step {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    flex: 1;
    padding: 0.5rem 0.75rem;
    min-width: 120px;
}

.flow__icon {
    width: 52px;
    height: 52px;
    background: rgba(37,99,235,0.07);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--c-accent);
    margin-bottom: 0.9rem;
    flex-shrink: 0;
}

.flow__icon svg {
    width: 22px;
    height: 22px;
}

.flow__content {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}

.flow__content strong {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--c-dark);
}

.flow__content span {
    font-size: 0.78rem;
    color: var(--c-muted);
    line-height: 1.4;
}

.flow__arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--c-accent);
    font-size: 1.4rem;
    padding: 0 0.25rem;
    flex-shrink: 0;
    opacity: 0.7;
    margin-bottom: 1.8rem; /* visual center with icon */
}

.case__result {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    background: rgba(22,163,74,0.05);
    border: 1px solid rgba(22,163,74,0.18);
    border-radius: var(--radius);
    padding: 1.25rem 1.5rem;
}

.case__result-icon {
    width: 26px;
    height: 26px;
    background: var(--c-success);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 700;
    flex-shrink: 0;
    margin-top: 1px;
}

.case__result p {
    font-size: 0.95rem;
    line-height: 1.65;
    color: var(--c-text);
}

/* ============================================================
   Tabs
   ============================================================ */

.tabs {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.tabs__btn {
    background: transparent;
    border: 1.5px solid var(--c-border);
    border-radius: 999px;
    color: var(--c-muted);
    font-family: var(--font);
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0.55rem 1.25rem;
    cursor: pointer;
    transition: background var(--ease), border-color var(--ease), color var(--ease);
    line-height: 1;
}

.tabs__btn--active {
    background: var(--c-accent);
    border-color: var(--c-accent);
    color: #fff;
}

.tabs__btn:hover:not(.tabs__btn--active) {
    background: rgba(37,99,235,0.06);
    border-color: var(--c-accent);
    color: var(--c-accent);
}

.tabs__panel[hidden] {
    display: none;
}

/* ============================================================
   Contact
   ============================================================ */

.contact__inner {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 5rem;
    align-items: start;
}

.contact__info h2 {
    margin-bottom: 1rem;
}

.contact__info p {
    color: var(--c-muted);
    font-size: 0.95rem;
    line-height: 1.75;
    margin-bottom: 0.9rem;
}

.contact__details {
    margin-top: 1.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.contact__detail {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.9rem;
    color: var(--c-text);
}

.contact__detail svg {
    width: 16px;
    height: 16px;
    color: var(--c-accent);
    flex-shrink: 0;
}

.contact__detail a {
    color: var(--c-accent);
    transition: color var(--ease);
}

.contact__detail a:hover {
    color: var(--c-accent-dark);
    text-decoration: underline;
}

/* Form */
.contact__form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--c-dark-mid);
}

.form-group input,
.form-group textarea {
    font-family: var(--font);
    font-size: 0.95rem;
    color: var(--c-text);
    background: var(--c-bg);
    border: 1.5px solid var(--c-border);
    border-radius: var(--radius);
    padding: 0.75rem 1rem;
    transition: border-color var(--ease), box-shadow var(--ease);
    outline: none;
    resize: vertical;
    width: 100%;
}

.form-group input:hover,
.form-group textarea:hover {
    border-color: #cbd5e1;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--c-accent);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: #a8b4c2;
}

.form-group input.error,
.form-group textarea.error {
    border-color: #dc2626;
}

.form-hint {
    font-size: 0.78rem;
    color: var(--c-muted);
    text-align: center;
    margin-top: -0.25rem;
}

.form-feedback {
    font-size: 0.95rem;
    line-height: 1.65;
    border-radius: var(--radius);
    padding: 1rem 1.25rem;
}

.form-feedback:empty {
    display: none;
}

.form-feedback--success {
    background: rgba(22,163,74,0.05);
    border: 1px solid rgba(22,163,74,0.25);
    color: var(--c-text);
}

.form-feedback--error {
    background: rgba(220,38,38,0.05);
    border: 1px solid rgba(220,38,38,0.25);
    color: var(--c-text);
}

/* ============================================================
   Footer
   ============================================================ */

.footer {
    background: var(--c-dark);
    padding: 2rem 0;
}

.footer__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.footer__left {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.footer__brand {
    color: #fff;
    font-weight: 700;
    font-size: 0.95rem;
    letter-spacing: -0.02em;
}

.footer__tagline {
    color: rgba(255,255,255,0.35);
    font-size: 0.8rem;
}

.footer__legal {
    display: flex;
    gap: 1.5rem;
}

.footer__legal a {
    color: rgba(255,255,255,0.35);
    font-size: 0.8rem;
    transition: color var(--ease);
}

.footer__legal a:hover {
    color: rgba(255,255,255,0.65);
}

/* ============================================================
   Responsive – Tablet (≤ 900px)
   ============================================================ */

@media (max-width: 900px) {
    .services__grid {
        grid-template-columns: 1fr 1fr;
    }
}

/* ============================================================
   Responsive – Mobile (≤ 768px)
   ============================================================ */

@media (max-width: 768px) {

    /* Nav – mobile overlay */
    .burger {
        display: flex;
    }

    .nav {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--c-dark);
        flex-direction: column;
        align-items: stretch;
        padding: 1.5rem;
        gap: 0.25rem;
        transform: translateY(-110%);
        transition: transform 0.3s ease;
        box-shadow: 0 8px 24px rgba(0,0,0,0.3);
    }

    .nav.open {
        transform: translateY(0);
    }

    .nav__link {
        font-size: 1rem;
        color: rgba(255,255,255,0.8) !important;
        padding: 0.75rem 0;
        border-bottom: 1px solid rgba(255,255,255,0.06);
    }

    .nav__link:last-child {
        border-bottom: none;
    }

    .nav__cta {
        text-align: center;
        border: 1.5px solid rgba(255,255,255,0.3) !important;
        border-radius: var(--radius);
        margin-top: 0.5rem;
        padding: 0.75rem !important;
        color: #fff !important;
    }

    /* Services */
    .services__grid {
        grid-template-columns: 1fr;
    }

    /* Case study flow – vertical */
    .flow {
        flex-direction: column;
        padding: 1.5rem;
        gap: 0;
    }

    .flow__step {
        flex-direction: row;
        text-align: left;
        align-items: center;
        padding: 0.75rem 0;
        min-width: unset;
    }

    .flow__icon {
        margin-bottom: 0;
        margin-right: 1rem;
        flex-shrink: 0;
    }

    .flow__arrow {
        padding: 0;
        margin: 0;
        padding-left: 1.6rem;
        font-size: 1.2rem;
        justify-content: flex-start;
    }

    /* Contact */
    .contact__inner {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    /* Footer */
    .footer__inner {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* ============================================================
   Responsive – Small Mobile (≤ 480px)
   ============================================================ */

@media (max-width: 480px) {
    .section {
        padding: 3.5rem 0;
    }

    .hero {
        padding: 6rem 1.25rem 4rem;
    }

    .hero__btns {
        flex-direction: column;
        align-items: stretch;
    }

    .hero__btns .btn {
        text-align: center;
    }

    .card {
        padding: 1.5rem;
    }
}