/* ===========================
   FONT (ĐẶT ĐẦU TIÊN)
=========================== */
@import url('https://fonts.googleapis.com/css2?family=Urbanist:wght@300;400;500;600;700&display=swap');

@font-face {
    font-family: 'General Sans';
    src: url('font/GeneralSans-Variable.woff2') format('woff2');
    font-weight: 100 900;
    font-style: normal;
}

/* ===========================
   CSS VARIABLES & THEMES
=========================== */
:root {
    --hover-color: #8a8a8a;
    --click-color: #A3C9F1;
    --bg-main: #ffffff;
    --text-main: #333;
    --navbar-bg: #ffffff;
    --navbar-text: #333;
}

body.dark {
    --bg-main: #000000;
    --text-main: #ffffff;
    --navbar-bg: #000000;
    --navbar-text: #ffffff;
}

/* ===========================
   BASE
=========================== */
body {
    overflow-x: hidden;
    font-family: 'Urbanist', sans-serif; /* body dùng Urbanist */
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    background-color: var(--bg-main);
    color: var(--text-main);
}

/* ===========================
   HEADER
=========================== */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 60px;
    background-color: var(--navbar-bg);
    transition: background-color 0.3s ease;
    position: relative;
    z-index: 9999;
    font-family: 'General Sans', sans-serif; /* navbar dùng General Sans */
}

.logo-img {
    height: 65px;
    width: auto;
}

/* ===========================
   MAIN NAV
=========================== */
.main-nav {
    display: flex;
    align-items: center;
}

.main-menu {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    font-size: 20px;
    font-family: 'General Sans', sans-serif;
}

.main-menu li { margin-right: 30px; }

.nav-item {
    text-decoration: none;
    color: var(--navbar-text);
    padding: 5px 0;
    display: block;
    transition: color 0.2s;
    font-family: 'General Sans', sans-serif;
}

.main-item:hover { color: var(--hover-color); }
.main-item.active,
.main-item.clicked { color: var(--click-color); }
body.dark .main-item.active,
body.dark .main-item.clicked { color: var(--click-color); }

/* ===========================
   NAV ACTIONS
=========================== */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 20px;
    position: relative;
}

/* ===========================
   THEME TOGGLE
=========================== */
.theme-toggle {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    outline: 1px solid var(--navbar-text);
    background-color: #000;
    transition: background-color 0.3s ease;
}

body.dark .theme-toggle { background-color: #fff; }

/* ===========================
   HAMBURGER
=========================== */
.hamburger-menu {
    cursor: pointer;
    width: 24px;
    height: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 2px;
    transition: transform 0.3s;
}

.bar {
    width: 100%;
    height: 1.5px;
    background-color: var(--navbar-text);
    border: none;
    box-shadow: none;
    transition: all 0.3s;
}

.hamburger-menu.active .bar:nth-child(1) { transform: rotate(-45deg) translate(-5px, 8px); }
.hamburger-menu.active .bar:nth-child(2) { opacity: 0; }
.hamburger-menu.active .bar:nth-child(3) { transform: rotate(45deg) translate(-5px, -8px); }

/* ===========================
   DROPDOWN
=========================== */
.dropdown-menu {
    list-style: none;
    padding: 10px 20px;
    margin: 0;
    position: absolute;
    top: 70px;
    right: 0;
    background: transparent;
    box-shadow: none;
    z-index: 1000;
    min-width: 150px;
    text-align: right;
    display: none;
    opacity: 0;
    transform: translateY(-10px);
    transition: opacity 0.3s ease-out, transform 0.3s ease-out;
    font-family: 'General Sans', sans-serif;
}

.dropdown-menu.visible {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.dropdown-menu li { padding: 8px 85px; }
.dropdown-menu a { color: var(--navbar-text); }
.sub-item { font-size: 16px; padding: 0; }
.sub-item:hover { color: var(--hover-color); }
.sub-item.active,
.sub-item.clicked { color: var(--click-color); }


.Overview {
    position: relative;
    padding: 20px 0 0;
    background: linear-gradient(180deg, #5C0200 0%, #ea4422 25%, #FFB404 50%, #FBE6B6 80%);
    overflow: hidden;
    width: 100%;
}

.Little-detail-overview { font-size: 14px; display: flex; color: white; justify-content: space-between; margin: 5px 60px; }

.Title {
    position: absolute;
    top: 60px;
    left: 50%;
    transform: translateX(-50%);
    font-size: clamp(40px, 18vw, 260px);
    font-weight: 500;
    color: white;
    opacity: 0.2;
    z-index: 2;
    white-space: nowrap;
    pointer-events: none;
}

.hand-img {
    display: block;
    margin: 63px auto 0;
    width: 100%;
    max-width: 900px;
    height: auto;
    object-fit: contain;
    position: relative;
    z-index: 3;
}

.black-img {
    width: 100%;
    height: 720px;
    background: black;
    border-radius: 20px 20px 0 0;
    overflow: hidden;
    position: relative;
    z-index: 1;
    display: flex;
    justify-content: flex-end;
    align-items: center;
}

.black-img img { height: 100%; width: auto; object-fit: contain; }

.overview-text {
    font-size: 18px;
    max-width: 100%;
    width: 100%;
    padding: 20px 60px;
    line-height: 1.5;
    box-sizing: border-box;
    overflow-wrap: break-word;
    word-break: break-word;
}

.phone-black-img {
    height: 620px;
    background: black;
    border-radius: 20px 20px 0 0;
    display: flex;
    justify-content: center;
    align-items: center;
}

.phone-black-img img { height: 100%; width: auto; object-fit: contain; }

.design-process { background: #000; padding: 80px 60px; color: #fff; }

.design-process .title { font-size: 64px; font-weight: 700; line-height: 1.2; margin-bottom: 60px; }

.design-thinking { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 20px 0; }

.step {
    background: transparent;
    border: 1.5px solid rgba(255, 255, 255, 0.6);
    color: #fff;
    padding: 20px 48px 20px 38px;
    border-radius: 999px;
    font-size: 18px;
    cursor: pointer;
    position: relative;
    white-space: nowrap;
    display: inline-block;
    font-family: 'Urbanist', sans-serif;
}

.step::after { content: "↗"; position: absolute; right: 18px; top: 50%; transform: translateY(-50%); color: #ff3b3b; font-size: 18px; }

.step:hover { border-color: #fff; transform: translateY(-2px); transition: all 0.25s ease; }

.research {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 60px;
    position: relative;
    background: linear-gradient(180deg, #5C0200 0%, #ea4422 25%, #FFB404 50%, #FBE6B6 100%);
    overflow: hidden;
}

.research::before {
    content: '';
    position: absolute;
    top: 30px; left: 30px; right: 30px; bottom: 30px;
    background-color: var(--bg-main);
    border-radius: 10px;
    z-index: 1;
}

.research > div { width: 100%; position: relative; z-index: 2; margin-top: 40px; }
.research > div:first-child { margin-top: 0; }

.research h1 { font-size: 30px; font-weight: 700; color: #FFB404; margin: 0 0 20px; position: relative; z-index: 2; }

.research-img { width: 85%; height: auto; object-fit: contain; display: block; margin: 0 auto; position: relative; z-index: 2; }

.research-img + .research-img { margin-top: 20px; }

.persona { width: 100%; margin: 40px 0; text-align: center; }

.persona-title { background: #e53935; color: white; padding: 18px 24px; border-radius: 40px; font-size: 22px; font-weight: 500; max-width: 1000px; margin: 20px auto; }

.persona p { max-width: 900px; margin: 0 auto; font-size: 18px; line-height: 1.6; color: #333; }

.research-findings { width: 100%; position: relative; z-index: 2; margin-top: 40px; }

.research-note { font-size: 16px; color: #1B2021; font-style: italic; margin: 0 0 24px; }

.findings-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }

.findings-col { font-size: 17px; color: #1B2021; line-height: 1.7; }
.findings-col p { margin: 0 0 12px; }
.findings-col ul { margin: 0 0 12px 16px; padding: 0; }
.findings-col ul li { margin-bottom: 8px; }
.findings-col strong { color: #FFB404; font-size: 20px; }

.design-system-title { background: #000; padding: 80px 60px; color: #fff; margin-top: -20px; }

.design-system-title h1 { font-size: 64px; font-weight: 700; color: #fff; margin: 0; }

.design-system {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
    padding: 60px;
    position: relative;
    background: linear-gradient(180deg, #5C0200 0%, #ea4422 25%, #FFB404 50%, #FBE6B6 100%);
    overflow: hidden;
}

.design-system::before {
    content: '';
    position: absolute;
    top: 30px; left: 30px; right: 30px; bottom: 30px;
    background-color: var(--bg-main);
    border-radius: 10px;
    z-index: 1;
}

.design-system h1 { font-size: 30px; font-weight: 700; color: #FFB404; margin: 0 0 20px; position: relative; z-index: 2; width: 100%; }

.design-img { width: 85%; height: auto; object-fit: contain; display: block; margin: 20px auto; position: relative; z-index: 2; }

.design-img + .design-img { margin-top: 20px; }

.wireframe { background: #000; padding: 40px 60px; overflow: hidden; }

.wireframe h1 { font-size: 30px; color: #FFB404; margin: 0 0 40px; }

.wireframe-img { width: 100%; max-width: 1200px; height: auto; display: block; margin: 0 auto; }

.mockup-phone-1 { background: #ffffff; padding: 60px; overflow: hidden; }

.mockup-phone-1 h1 { font-size: 30px; color: #FFB404; margin: 0 0 40px; }

.mockup-phone-1 img { width: 100%; max-width: 1200px; height: auto; object-fit: contain; display: block; margin: 0 auto; }

.video-prototype { background: #ffffff; padding: 20px 0; margin-top: 40px; }

.video-prototype-img { width: 100%; height: auto; display: block; pointer-events: none; }

.video-prototype-img::-webkit-media-controls,
.video-prototype-img::-webkit-media-controls-enclosure { display: none !important; }

.mockup-layout {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 40px;
    padding: 40px 60px 120px;
    margin-top: -20px;
    margin-bottom: -80px;
    overflow: hidden;
}

.title-mockup { font-size: 30px; color: #FFB404; margin: 0; }

.mockup-layout-img { width: 100%; max-width: 1400px; height: auto; object-fit: contain; display: block; }

.main-footer { width: 100%; height: 250px; background-color: #A3C9F1; margin-top: 100px; position: relative; }

.logo-footer { display: flex; justify-content: left; align-items: center; padding: 40px 60px; }
.footer { display: flex; justify-content: space-between; padding: 60px 60px 0; flex-wrap: wrap; gap: 8px; }

.back-to-top { position: absolute; top: 40px; right: 60px; background: none; font-size: 18px; text-decoration: none; color: #000; font-weight: 500; cursor: pointer; z-index: 5; transition: transform 0.2s ease; }

.back-to-top:hover { transform: scale(1.05); }

.footer a { color: #000; text-decoration: none; }
.footer a:hover { text-decoration: underline; }

.footer-highlight { font-size: 20px; font-weight: 500; color: #000; text-decoration: none; }