/* =============================================
   CSS Variables & Reset
============================================= */
* {
    font-family: 'Noto Sans KR', sans-serif;
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #0c479b;
    --primary-hover: #093475;
    --primary-light: rgba(12, 71, 155, 0.08);

    --secondary-color: #00abe4;
    --secondary-hover: #0092c4;
    --secondary-light: rgba(0, 171, 228, 0.08);

    --deep-navy: #0b1a32;
    --mid-navy: #1a3a6b;

    --bg-color: #f5f4f0;
    --bg-card: #ffffff;
    --text-main: #0d1b2a;
    --text-muted: #4a5a6e;
    --text-light: #8fa1b3;

    --glass-bg: rgba(255, 255, 255, 0.90);
    --glass-bg-hover: rgba(255, 255, 255, 0.97);
    --glass-border: rgba(200, 215, 230, 0.45);
    --glass-border-solid: #dce5ef;

    --shadow-sm: 0 2px 8px rgba(11, 26, 50, 0.07);
    --shadow-md: 0 8px 28px rgba(11, 26, 50, 0.09);
    --shadow-lg: 0 24px 52px rgba(11, 26, 50, 0.13);
    --shadow-header: 0 12px 40px rgba(11, 26, 50, 0.22);

    --radius-sm: 10px;
    --radius-md: 16px;
    --radius-lg: 22px;

    --transition: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    position: relative;
    overflow-x: hidden;
    min-height: 100vh;
    font-size: 18px;
    line-height: 1.8;
    /* Warm-tinted dot grid */
    background-image: radial-gradient(rgba(11, 26, 50, 0.045) 1px, transparent 1px);
    background-size: 24px 24px;
}

/* Top-left ambient glow */
body::before {
    content: '';
    position: fixed;
    top: -15%;
    left: -12%;
    width: 55vw;
    height: 55vw;
    min-width: 350px;
    min-height: 350px;
    background: radial-gradient(circle, rgba(0, 171, 228, 0.09) 0%, transparent 62%);
    border-radius: 50%;
    filter: blur(70px);
    z-index: -1;
    pointer-events: none;
    animation: pulse-slow 18s infinite alternate;
}

/* Bottom-right ambient glow */
body::after {
    content: '';
    position: fixed;
    bottom: -12%;
    right: -8%;
    width: 48vw;
    height: 48vw;
    min-width: 320px;
    min-height: 320px;
    background: radial-gradient(circle, rgba(12, 71, 155, 0.07) 0%, transparent 62%);
    border-radius: 50%;
    filter: blur(80px);
    z-index: -1;
    pointer-events: none;
    animation: pulse-slow 24s infinite alternate-reverse;
}

@keyframes pulse-slow {
    0% { transform: scale(1) translate(0, 0); }
    50% { transform: scale(1.07) translate(2%, 2%); }
    100% { transform: scale(0.94) translate(-2%, -2%); }
}

@keyframes fadeInUp {
    0% { opacity: 0; transform: translateY(28px); }
    100% { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    0% { opacity: 0; }
    100% { opacity: 1; }
}

@keyframes slideDown {
    0% { opacity: 0; transform: translateY(-10px); }
    100% { opacity: 1; transform: translateY(0); }
}

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

button {
    cursor: pointer;
    border: none;
    background: none;
    font-family: inherit;
}

ul, ol {
    list-style: none;
}

/* =============================================
   Glass Panel (공통)
============================================= */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
}

.glass-panel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.9), transparent);
    z-index: 1;
}

/* =============================================
   Container
============================================= */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

/* =============================================
   Page Header
============================================= */
.page-header {
    padding: 52px 20px 44px;
    text-align: center;
    position: relative;
    z-index: 2;
    animation: fadeInUp 0.9s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.page-header__logo {
    margin-bottom: 28px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

/* Accent line below logo */
.page-header__logo::after {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 50%;
    transform: translateX(-50%);
    width: 36px;
    height: 2px;
    background: linear-gradient(90deg, var(--secondary-color), var(--primary-color));
    border-radius: 2px;
}

.logo-image {
    max-width: 160px;
    height: auto;
}

.page-header__title {
    font-size: 30px;
    font-weight: 900;
    color: var(--text-main);
    letter-spacing: -0.8px;
    line-height: 1.25;
    word-break: keep-all;
    margin-top: 20px;
}

.page-header__desc {
    font-size: 15px;
    color: var(--text-muted);
    margin-top: 16px;
    line-height: 1.8;
    max-width: 460px;
    margin-left: auto;
    margin-right: auto;
    word-break: keep-all;
    font-weight: 400;
}

/* =============================================
   Scroll Spy Navigation
============================================= */
.scroll-spy-nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(245, 244, 240, 0.90);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--glass-border-solid);
    padding: 10px 0;
    transition: var(--transition);
    animation: slideDown 0.6s cubic-bezier(0.16, 1, 0.3, 1) both;
    animation-delay: 0.25s;
}

.scroll-spy-nav__list {
    display: flex;
    justify-content: center;
    gap: 8px;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 16px;
}

.scroll-spy-nav__item {
    flex: 1;
    text-align: center;
}

.scroll-spy-nav__link {
    display: block;
    padding: 10px 12px;
    font-size: 14px;
    font-weight: 700;
    color: var(--text-muted);
    transition: var(--transition);
    position: relative;
    word-break: keep-all;
    border-radius: 10px;
}

/* Remove old underline indicator */
.scroll-spy-nav__link::after {
    display: none;
}

.scroll-spy-nav__link.active {
    color: var(--primary-color);
    background: rgba(12, 71, 155, 0.08);
}

.scroll-spy-nav__link:hover:not(.active) {
    color: var(--text-main);
    background: rgba(11, 26, 50, 0.04);
}

/* =============================================
   Main Accordion Sections
============================================= */
.section {
    margin-bottom: 20px;
    animation: fadeInUp 0.7s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.section:nth-child(1) { animation-delay: 0.05s; }
.section:nth-child(2) { animation-delay: 0.15s; }
.section:nth-child(3) { animation-delay: 0.25s; }

.section__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 22px 24px;
    /* Deep midnight → brand blue gradient — more premium than bright cyan */
    background: linear-gradient(135deg, var(--deep-navy) 0%, var(--mid-navy) 55%, var(--primary-color) 100%);
    color: #fff;
    font-size: 19px;
    font-weight: 800;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-header);
    text-align: left;
    word-break: keep-all;
    line-height: 1.4;
    border: none;
    position: relative;
    overflow: hidden;
    letter-spacing: -0.3px;
}

/* Top sheen line */
.section__header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.28), transparent);
    pointer-events: none;
}

/* Subtle cyan accent wash on right side */
.section__header::after {
    content: '';
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
    width: 90px;
    background: linear-gradient(to left, rgba(0, 171, 228, 0.14), transparent);
    pointer-events: none;
    border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
}

.section__header:hover {
    transform: translateY(-2px);
    box-shadow: 0 18px 52px rgba(11, 26, 50, 0.30);
}

.section__header:active {
    transform: translateY(0);
}

.section__header-icon {
    font-size: 11px;
    margin-left: 14px;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), background 0.28s ease;
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.14);
    border: 1px solid rgba(255, 255, 255, 0.20);
    border-radius: 50%;
    position: relative;
    z-index: 1;
}

.section.open .section__header-icon {
    transform: rotate(180deg);
    background: rgba(0, 171, 228, 0.28);
    border-color: rgba(0, 171, 228, 0.5);
}

.section.open .section__header {
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}

/* AEO/GEO friendly: content is not display:none, uses max-height for SEO crawlability */
.section__content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-top: none;
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.section.open .section__content {
    max-height: 5000px;
    transition: max-height 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.section__content-inner {
    padding: 28px 24px 32px;
    /* CSS counter for automatic video numbering */
    counter-reset: video-counter;
}

/* =============================================
   Video Card
============================================= */
.video-card {
    margin-bottom: 32px;
    counter-increment: video-counter;
}

.video-card:last-child {
    margin-bottom: 0;
}

.video-card__title {
    font-size: 17px;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 14px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    line-height: 1.5;
    word-break: keep-all;
    position: relative;
    /* Space for counter badge */
    padding-left: 46px;
}

/* Automatic numbered badge — no HTML changes needed */
.video-card__title::before {
    content: counter(video-counter, decimal-leading-zero);
    position: absolute;
    left: 0;
    top: 0;
    font-size: 12px;
    font-weight: 900;
    color: #fff;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    width: 33px;
    height: 33px;
    border-radius: 9px;
    text-align: center;
    line-height: 33px;
    letter-spacing: 0;
    box-shadow: 0 4px 12px rgba(12, 71, 155, 0.28);
    flex-shrink: 0;
}

.video-card__title-icon {
    font-size: 22px;
    flex-shrink: 0;
    margin-top: 2px;
}

.video-card__embed {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 */
    height: 0;
    overflow: hidden;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    background: #000;
    border: 1px solid var(--glass-border-solid);
}

.video-card__embed iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
    border-radius: var(--radius-md);
}

.video-card__desc {
    font-size: 14px;
    color: var(--text-muted);
    margin-top: 10px;
    line-height: 1.65;
    word-break: keep-all;
    font-weight: 400;
}

/* =============================================
   Divider
============================================= */
.content-divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--glass-border-solid), transparent);
    margin: 28px 0;
}

/* =============================================
   FAQ Section
============================================= */
.faq-section {
    margin-top: 8px;
}

.faq-section__title {
    font-size: 18px;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 10px;
    letter-spacing: -0.3px;
}

/* Vertical accent bar before FAQ heading */
.faq-section__title::before {
    content: '';
    display: inline-block;
    width: 4px;
    height: 22px;
    background: linear-gradient(180deg, var(--secondary-color), var(--primary-color));
    border-radius: 3px;
    flex-shrink: 0;
}

.faq-placeholder {
    background: var(--secondary-light);
    border: 1px dashed var(--secondary-color);
    border-radius: var(--radius-md);
    padding: 24px;
    text-align: center;
    color: var(--text-muted);
    font-size: 16px;
    font-weight: 500;
}

/* FAQ Accordion Items */
.faq-item {
    margin-bottom: 8px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    border: 1px solid var(--glass-border-solid);
    background: var(--bg-card);
    transition: var(--transition);
    position: relative;
}

/* Left accent bar — revealed on open via scaleY */
.faq-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, var(--secondary-color), var(--primary-color));
    transform: scaleY(0);
    transform-origin: center;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-item:hover {
    box-shadow: var(--shadow-sm);
    border-color: #c4d4e8;
}

.faq-item.open {
    box-shadow: var(--shadow-md);
    border-color: #b8cce4;
}

.faq-item.open::before {
    transform: scaleY(1);
}

.faq-item__question {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 18px 20px;
    font-size: 16px;
    font-weight: 700;
    color: var(--text-main);
    cursor: pointer;
    background: transparent;
    text-align: left;
    transition: var(--transition);
    gap: 12px;
    word-break: keep-all;
    line-height: 1.5;
}

.faq-item__question:hover {
    background: rgba(0, 171, 228, 0.03);
}

.faq-item__question-icon {
    font-size: 10px;
    color: var(--text-light);
    transition: transform 0.3s ease, color 0.3s ease, background 0.3s ease;
    flex-shrink: 0;
    width: 26px;
    height: 26px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #edf1f7;
    border-radius: 50%;
}

.faq-item.open .faq-item__question-icon {
    transform: rotate(180deg);
    background: var(--secondary-light);
    color: var(--secondary-color);
}

.faq-item.open .faq-item__question {
    color: var(--primary-color);
    background: rgba(12, 71, 155, 0.025);
    border-bottom: 1px solid var(--glass-border-solid);
}

/* AEO/GEO: use max-height instead of display:none */
.faq-item__answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-item.open .faq-item__answer {
    max-height: 600px;
}

.faq-item__answer-inner {
    padding: 16px 20px 20px;
    font-size: 15px;
    color: var(--text-muted);
    line-height: 1.85;
    word-break: keep-all;
    font-weight: 400;
}

.faq-item__answer-inner strong {
    color: var(--primary-color);
    font-weight: 700;
}

/* =============================================
   CTA Section
============================================= */
.cta-section {
    margin: 40px 0 24px;
    text-align: center;
    animation: fadeInUp 0.6s ease;
}

.cta-card {
    padding: 40px 28px;
    text-align: center;
    /* Override glass-panel: dark panel look */
    background: linear-gradient(135deg, var(--deep-navy) 0%, var(--mid-navy) 60%, var(--primary-color) 100%) !important;
    border: none !important;
    box-shadow: var(--shadow-header) !important;
}

/* Keep glass-panel sheen on CTA card */
.cta-card.glass-panel::before {
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.35), transparent);
}

.cta-card__icon {
    font-size: 40px;
    margin-bottom: 14px;
}

.cta-card__title {
    font-size: 21px;
    font-weight: 800;
    color: #fff;
    margin-bottom: 10px;
    word-break: keep-all;
    letter-spacing: -0.4px;
}

.cta-card__desc {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.72);
    line-height: 1.8;
    margin-bottom: 24px;
    word-break: keep-all;
    font-weight: 400;
}

.cta-card__desc strong {
    color: #ffffff;
    font-weight: 700;
}

.cta-card__button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 15px 40px;
    background: #fff;
    color: var(--primary-color);
    font-size: 16px;
    font-weight: 800;
    border-radius: 32px;
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.22);
    text-decoration: none;
    min-height: 52px;
    letter-spacing: -0.2px;
}

.cta-card__button:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.30);
    background: #eef4ff;
}

/* =============================================
   Footer
============================================= */
.page-footer {
    text-align: center;
    padding: 28px 20px 44px;
    font-size: 13px;
    color: var(--text-light);
    line-height: 1.6;
}

.page-footer a {
    color: var(--text-muted);
    text-decoration: underline;
    text-underline-offset: 3px;
    transition: color 0.2s ease;
}

.page-footer a:hover {
    color: var(--primary-color);
}

/* =============================================
   Back to Top Button
============================================= */
.back-to-top {
    position: fixed;
    bottom: 28px;
    right: 20px;
    width: 48px;
    height: 48px;
    background: var(--deep-navy);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.10);
    border-radius: 12px;
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 6px 24px rgba(11, 26, 50, 0.32);
    cursor: pointer;
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 200;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    background: var(--primary-color);
    box-shadow: 0 10px 30px rgba(12, 71, 155, 0.42);
}

/* =============================================
   Always-Expanded Mode (no accordion)
============================================= */
/* Static section header — not clickable */
.section__header--static {
    cursor: default;
}

.section__header--static:hover {
    transform: none;
    box-shadow: var(--shadow-header);
}

.section__header--static:active {
    transform: none;
}

/* Always-expanded section content */
.section--static.open .section__content {
    max-height: none;
}

/* Static FAQ items — always expanded, not clickable */
.faq-item--static .faq-item__question {
    cursor: default;
}

.faq-item--static .faq-item__question:hover {
    background: transparent;
}

.faq-item--static.open .faq-item__answer {
    max-height: none;
}

/* =============================================
   Responsive — Tablet (768px+)
============================================= */
@media (min-width: 768px) {
    .page-header {
        padding: 64px 40px 52px;
    }

    .page-header__title {
        font-size: 38px;
        letter-spacing: -1.2px;
    }

    .page-header__desc {
        font-size: 16px;
    }

    .section__header {
        font-size: 21px;
        padding: 24px 32px;
    }

    .section__content-inner {
        padding: 36px 32px 40px;
    }

    .video-card__title {
        font-size: 18px;
    }

    .faq-item__question {
        font-size: 17px;
        padding: 20px 24px;
    }

    .faq-item.open .faq-item__question {
        border-bottom: 1px solid var(--glass-border-solid);
    }

    .faq-item__answer-inner {
        padding: 16px 24px 24px;
        font-size: 16px;
    }

    .container {
        padding: 0 32px;
    }

    .scroll-spy-nav__link {
        font-size: 15px;
        padding: 10px 20px;
    }

    .scroll-spy-nav__list {
        gap: 12px;
    }
}

/* =============================================
   Responsive — Desktop (1024px+)
============================================= */
@media (min-width: 1024px) {
    .page-header__title {
        font-size: 44px;
        letter-spacing: -1.6px;
    }

    .section__header {
        font-size: 22px;
        padding: 26px 36px;
    }

    .video-card__title {
        font-size: 19px;
    }

    .back-to-top {
        right: 32px;
        bottom: 32px;
    }
}