/* static/css/about.css */

/* =========================================
   0. VARIABLES & COMMON
   ========================================= */
:root {
    --toss-blue: #3182F6;
    --toss-dark: #191F28;     /* 깊은 네이비 블랙 */
    --toss-gray: #333D4B;     /* 진한 회색 텍스트 */
    --toss-light-gray: #B0B8C1; /* 연한 회색 */
    --toss-bg: #F2F4F6;       /* 배경용 연회색 */
    --alert-red: #FF4D4D;     /* 강조용 레드 */
    --white: #FFFFFF;
}

body {
    margin: 0;
    font-family: 'Pretendard', sans-serif;
    line-height: 1.6;
    color: var(--toss-dark);
    overflow-x: hidden;
    font-size: 1.125rem; /* 18px */
}

.about-main {
    width: 100%;
}

.container {
    max-width: 75rem; /* 1200px */
    margin: 0 auto;
    padding: 0 1.5rem; /* 24px */
    position: relative;
}

.section {
    padding: 11.25rem 0; /* 섹션 간 넉넉한 여백 */
}

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

/* --- Scroll Animation --- */
.scroll-reveal {
    opacity: 0;
    transform: translateY(3.75rem);
    transition: all 1s cubic-bezier(0.16, 1, 0.3, 1);
}
.scroll-reveal.active {
    opacity: 1;
    transform: translateY(0);
}
.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }
.delay-4 { transition-delay: 0.4s; }
.delay-5 { transition-delay: 0.5s; }


/* =========================================
   1. HERO SECTION
   ========================================= */
.hero-section {
    background-color: #000000;
    color: var(--white);
    padding: 10rem 0 13.75rem;
    text-align: center;
}

.hero-title {
    font-size: 4.5rem; 
    font-weight: 800;
    line-height: 1.3;
    margin-bottom: 3.125rem;
    color: var(--toss-light-gray);
    word-break: keep-all;
}

.hero-title .text-white {
    color: var(--white);
}

.highlight-red {
    color: var(--alert-red);
    display: inline-block;
}

.hero-desc {
    font-size: 1.9rem;
    color: #8B95A1;
    margin-bottom: 4.375rem;
    font-weight: 500;
    line-height: 1.5;
    word-break: keep-all;
}

/* 텍스트 강조 (Blue) */
.highlight-text {
    font-weight: 700;
    color: var(--white);
    position: relative;
    z-index: 1;
    padding: 0 4px;
}

.highlight-text.blue {
    color: #6da5ff;
}

.highlight-text::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 0;
    width: 100%;
    height: 30%;
    background-color: rgba(255, 255, 255, 0.2);
    z-index: -1;
    border-radius: 2px;
}
.highlight-text.blue::after {
    background-color: rgba(49, 130, 246, 0.3);
}

.btn-hero {
    display: inline-block;
    padding: 1.5rem 3.5rem;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--white);
    background-color: var(--toss-blue);
    border-radius: 1.125rem;
    transition: transform 0.2s, background-color 0.2s;
    text-decoration: none;
}
.btn-hero:hover {
    background-color: #1B64DA;
    transform: scale(1.02);
}


/* =========================================
   2. PROBLEM SECTION
   ========================================= */
.problem-section {
    background-color: var(--white);
    text-align: center;
}

.section-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 6.25rem;
    line-height: 1.3;
    word-break: keep-all;
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.875rem;
    margin-bottom: 6.25rem;
}

.problem-card {
    background-color: var(--toss-bg);
    padding: 3.125rem 2rem;
    border-radius: 1.875rem;
    text-align: left;
    transition: transform 0.3s;
}
.problem-card:hover {
    transform: translateY(-0.75rem);
}

.problem-card .icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.problem-card h3.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--toss-dark);
}

.problem-card p {
    font-size: 1.125rem;
    font-weight: 500;
    color: #4E5968;
    word-break: keep-all;
    line-height: 1.5;
}

.problem-message {
    font-size: 2.8rem;
    font-weight: 500;
    line-height: 1.6;
    word-break: keep-all;
}
.problem-message strong {
    font-weight: 800;
    color: var(--toss-blue);
    background: linear-gradient(to top, rgba(49, 130, 246, 0.1) 40%, transparent 40%);
}


/* =========================================
   3. STORY SECTION
   ========================================= */
.story-section {
    background-color: #F9FAFB;
    padding: 12.5rem 0;
}

.story-content {
    max-width: 50rem;
    margin: 0 auto;
}

.badge {
    display: inline-block;
    padding: 0.625rem 1.25rem;
    background-color: rgba(25, 31, 40, 0.08);
    color: var(--toss-gray);
    font-weight: 700;
    border-radius: 2rem;
    margin-bottom: 1.875rem;
    font-size: 1rem;
}

.story-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 3.75rem;
    line-height: 1.4;
    word-break: keep-all;
}

.story-body p {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    color: #4E5968;
    line-height: 1.8;
    word-break: keep-all;
}

.story-highlight {
    font-size: 1.6rem !important;
    font-weight: 700;
    color: var(--toss-dark) !important;
    margin-top: 3.75rem;
    padding-left: 1.5rem;
    border-left: 0.3125rem solid var(--toss-dark);
}


/* =========================================
   4. CORE SECTION (수정됨: 아이콘 4개 배치)
   ========================================= */
.core-section {
    background-color: var(--toss-dark);
    color: var(--white);
    text-align: center;
    padding: 14rem 0;
}

.core-title {
    font-size: 3.75rem;
    font-weight: 800;
    margin-bottom: 4rem;
    line-height: 1.3;
    word-break: keep-all;
}

.highlight-blue {
    color: var(--toss-blue);
}

.core-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr); /* 4열 */
    gap: 1.5rem;
    max-width: 80rem;
    margin: 0 auto;
}

.core-item {
    background-color: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1.5rem;
    padding: 3.5rem 1.5rem;
    transition: transform 0.3s ease, border-color 0.3s ease, background-color 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.core-item:hover {
    transform: translateY(-8px);
    border-color: var(--toss-blue);
    background-color: rgba(255, 255, 255, 0.08);
}

.core-icon-wrapper {
    width: 4.5rem;
    height: 4.5rem;
    background-color: rgba(49, 130, 246, 0.15);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 1.5rem;
    color: var(--toss-blue);
    font-size: 2.25rem;
}

.core-item-title {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--white);
    margin: 0 0 0.75rem 0;
}

.core-item-desc {
    font-size: 1.05rem;
    color: var(--toss-light-gray);
    margin: 0;
    line-height: 1.5;
    word-break: keep-all;
}


/* =========================================
   5. DIFFERENTIATION SECTION
   ========================================= */
.diff-section {
    background-color: var(--white);
    padding: 10rem 0;
}

.diff-container {
    display: flex;
    justify-content: center;
    gap: 2.5rem;
    align-items: stretch;
    margin-top: 5rem;
}

.diff-card {
    flex: 1;
    max-width: 35rem;
    padding: 3.75rem 3rem;
    border-radius: 2rem;
    transition: transform 0.3s ease;
}

.diff-card .card-header h3 {
    font-size: 2rem;
    font-weight: 800;
    line-height: 1.3;
    margin-bottom: 3.75rem;
    word-break: keep-all;
}

.card-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.card-list li {
    display: flex;
    align-items: flex-start;
    gap: 1.25rem;
}

.card-list .icon {
    font-size: 1.5rem;
    font-weight: 900;
    margin-top: 0.125rem;
    flex-shrink: 0;
}

.card-list .text-group {
    display: flex;
    flex-direction: column;
    gap: 0.375rem;
}

.card-list .main {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
    line-height: 1.4;
    word-break: keep-all;
}

.card-list .sub {
    font-size: 1rem;
    margin: 0;
    line-height: 1.5;
    word-break: keep-all;
}

/* Bad Case */
.diff-card.bad {
    background-color: var(--toss-bg);
    color: #6B7684;
}
.diff-card.bad .card-header h3 { color: #6B7684; }
.diff-card.bad .icon { color: var(--alert-red); }
.diff-card.bad .main { color: #6B7684; }
.diff-card.bad .sub { color: #8B95A1; }

/* Good Case */
.diff-card.good {
    background-color: var(--white);
    border: 0.125rem solid var(--toss-blue);
    box-shadow: 0 1.25rem 3.75rem rgba(49, 130, 246, 0.15);
    position: relative;
    transform: scale(1.02);
    z-index: 1;
}
.diff-card.good:hover {
    transform: scale(1.02) translateY(-0.625rem);
}
.diff-card.good .card-header h3 { color: var(--toss-blue); }
.diff-card.good .icon { color: var(--toss-blue); }
.diff-card.good .main { color: var(--toss-dark); }
.diff-card.good .sub { color: #4E5968; }


/* =========================================
   6. MISSION SECTION
   ========================================= */
.mission-section {
    text-align: center;
    padding: 15rem 0;
    background: linear-gradient(180deg, #FFFFFF 0%, #F2F4F6 100%);
}

.mission-sub {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--toss-blue);
    text-transform: uppercase;
    margin-bottom: 1.5rem;
    letter-spacing: 0.15rem;
}

.mission-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 3.125rem;
    line-height: 1.4;
    word-break: keep-all;
}

.mission-desc {
    font-size: 1.5rem;
    color: #6B7684;
    max-width: 43.75rem;
    margin: 0 auto;
    word-break: keep-all;
}


/* =========================================
   7. CTA FINAL
   ========================================= */
.cta-section {
    background-color: var(--toss-dark);
    text-align: center;
    padding: 15rem 0 16.25rem;
    color: var(--white);
}

.cta-title {
    font-size: 3.75rem;
    font-weight: 800;
    margin-bottom: 1.875rem;
    line-height: 1.3;
    word-break: keep-all;
}

.cta-desc {
    font-size: 1.6rem;
    color: var(--toss-light-gray);
    margin-bottom: 4.375rem;
    word-break: keep-all;
}

.btn-cta-final {
    display: inline-block;
    padding: 1.75rem 4.5rem;
    font-size: 1.6rem;
    font-weight: 700;
    background-color: var(--toss-blue);
    color: var(--white);
    border-radius: 1.5rem;
    text-decoration: none;
    transition: all 0.2s;
}
.btn-cta-final:hover {
    background-color: #1B64DA;
    transform: scale(1.05);
    box-shadow: 0 0.75rem 2.5rem rgba(49, 130, 246, 0.4);
}


/* =========================================
   MOBILE RESPONSIVE
   ========================================= */
@media (max-width: 768px) {
    /* 공통 */
    .section { padding: 5rem 0; }
    .container { padding: 0 1.25rem; }

    /* Hero */
    .hero-section { padding: 6rem 0 7rem; }
    .hero-title { font-size: 2.2rem; line-height: 1.35; }
    .hero-desc { font-size: 1.15rem; padding: 0 10px; margin-bottom: 3rem; }
    .btn-hero { width: 100%; padding: 1.2rem; font-size: 1.2rem; box-sizing: border-box; }

    /* Problem */
    .section-title { font-size: 2rem; margin-bottom: 3rem; }
    .problem-grid { grid-template-columns: 1fr; gap: 1.5rem; }
    .problem-message { font-size: 1.4rem; margin-top: 3rem; line-height: 1.5; }
    .problem-card { padding: 1rem 2rem; }
    .problem-card .icon {
        margin:0;
    }
    .problem-card h3 {
        margin:0;
    }

    /* Core Section Mobile */
    .core-section { padding: 6rem 0; }
    .core-title { font-size: 2rem; }
    .core-grid { 
        /* 모바일에서는 2열 2행으로 보기 좋게 배치 */
        grid-template-columns: repeat(2, 1fr); 
        gap: 1rem; 
    }
    .core-item { padding: 1.5rem 1rem; }
    .core-icon-wrapper { width: 3.5rem; height: 3.5rem; font-size: 1.75rem; margin-bottom: 1rem; }
    .core-item-title { font-size: 1.1rem; }
    .core-item-desc { font-size: 0.9rem; }

    .story-title {
        font-size : 2.3rem;
    }

    .story-highlight{
        font-size : 1.3rem;
        margin : 2rem 0.5rem;
        padding-left: 1rem;
    }

    /* Diff */
    .diff-section { padding: 5rem 0; }
    .diff-container { flex-direction: column; gap: 2.5rem; margin-top: 3rem; }
    .diff-card { max-width: 100%; padding: 2.5rem 1.5rem; }
    .diff-card .card-header h3 { font-size: 1.6rem; margin-bottom: 2rem; }
    .card-list { gap: 1.5rem; }
    .diff-card.good { transform: none; box-shadow: 0 0.5rem 1.5rem rgba(49, 130, 246, 0.1); }
    .diff-card.good:hover { transform: none; }

    /* Mission */
    .mission-section { padding: 6rem 0; }
    .mission-title { font-size: 2rem; }
    .mission-desc { font-size: 1.15rem; }

    /* CTA */
    .cta-section { padding: 6rem 0 8rem; }
    .cta-title { font-size: 2.2rem; }
    .cta-desc { font-size: 1.2rem; margin-bottom: 3rem; }
    .btn-cta-final { width: 100%; padding: 1.2rem; font-size: 1.2rem; box-sizing: border-box; }
}