:root {
    --excel-green: #1d6f42;
    --excel-green-dark: #185a36;
    --excel-green-light: #21a366;
    --excel-bg: #f7faf8;
    --text-dark: #1f2d3d;
    --border-soft: #e7eaee;
}

* {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

body {
    color: var(--text-dark);
    background: #ffffff;
    line-height: 1.65;
}

/* Bootstrap success color override to Excel green */
.btn-success {
    background-color: var(--excel-green);
    border-color: var(--excel-green);
}
.btn-success:hover,
.btn-success:focus {
    background-color: var(--excel-green-dark);
    border-color: var(--excel-green-dark);
}
.btn-outline-success {
    color: var(--excel-green);
    border-color: var(--excel-green);
}
.btn-outline-success:hover {
    background-color: var(--excel-green);
    border-color: var(--excel-green);
}
.text-success {
    color: var(--excel-green) !important;
}
.bg-success-subtle {
    background-color: #e8f5ee !important;
}
.text-success-emphasis {
    color: var(--excel-green-dark) !important;
}

/* Navbar */
.navbar {
    padding-top: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-soft);
}
.navbar-brand {
    font-size: 1.25rem;
    color: var(--text-dark);
}
.brand-icon {
    display: inline-block;
    transform: translateY(-1px);
    margin-right: 4px;
}
.nav-link {
    color: #4a5568;
    font-weight: 500;
    margin: 0 0.4rem;
    transition: color 0.2s;
}
.nav-link:hover,
.nav-link.active {
    color: var(--excel-green);
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #f0f9f3 0%, #ffffff 60%);
    padding: 5rem 0 6rem;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: "";
    position: absolute;
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(33, 163, 102, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}
.hero h1 {
    line-height: 1.15;
    letter-spacing: -0.5px;
}
.hero .lead {
    font-size: 1.15rem;
    max-width: 540px;
}

.stats-row {
    max-width: 480px;
}
.stat-card {
    background: #fff;
    border: 1px solid var(--border-soft);
    border-radius: 12px;
    padding: 1rem 0.75rem;
    text-align: center;
    transition: transform 0.2s, box-shadow 0.2s;
}
.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.06);
}
.stat-num {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--excel-green);
    line-height: 1.1;
}
.stat-label {
    font-size: 0.85rem;
    color: #6c757d;
    margin-top: 0.15rem;
}

/* Hero card (Excel mockup) */
.hero-card {
    background: #fff;
    border-radius: 14px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.15);
    overflow: hidden;
    border: 1px solid var(--border-soft);
    transform: rotate(-1deg);
    transition: transform 0.3s ease;
}
.hero-card:hover {
    transform: rotate(0deg) scale(1.02);
}
.hero-card-header {
    background: #f1f3f5;
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    gap: 6px;
    border-bottom: 1px solid var(--border-soft);
}
.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    display: inline-block;
}
.dot-red { background: #ff5f56; }
.dot-yellow { background: #ffbd2e; }
.dot-green { background: #27c93f; }

.hero-card-body {
    padding: 0;
}
.hero-table {
    width: 100%;
    font-size: 0.9rem;
    border-collapse: collapse;
}
.hero-table th,
.hero-table td {
    border: 1px solid var(--border-soft);
    padding: 0.5rem 0.75rem;
}
.hero-table thead th {
    background: var(--excel-green);
    color: white;
    font-weight: 600;
    text-align: center;
}
.hero-table thead th:first-child {
    background: #f1f3f5;
    color: #6c757d;
    width: 38px;
}
.hero-table tbody td:first-child {
    background: #f1f3f5;
    color: #6c757d;
    text-align: center;
    font-weight: 500;
    width: 38px;
}
.formula-row td {
    background: #fff8e1;
    color: var(--excel-green-dark);
    font-family: 'Consolas', 'Monaco', monospace;
    font-weight: 500;
    text-align: center;
}

/* Sections */
.section {
    padding: 5rem 0;
}
.section-light {
    background: var(--excel-bg);
}
.section-title {
    font-size: 2.25rem;
    font-weight: 800;
    margin-bottom: 1rem;
    text-align: center;
    letter-spacing: -0.5px;
}
.section-subtitle {
    font-size: 1.1rem;
    color: #6c757d;
    text-align: center;
    max-width: 640px;
    margin: 0 auto;
}

/* Feature cards */
.feature-card {
    background: #fff;
    border: 1px solid var(--border-soft);
    border-radius: 14px;
    padding: 2rem;
    height: 100%;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.07);
}
.feature-icon {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1.25rem;
}
.feature-card h4 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

/* Check list */
.check-list {
    list-style: none;
    padding: 0;
    margin: 0;
}
.check-list li {
    padding: 0.5rem 0;
    font-size: 1.05rem;
}

/* Program preview */
.program-preview {
    background: #fff;
    border: 1px solid var(--border-soft);
    border-radius: 14px;
    padding: 1rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.04);
}
.program-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    border-radius: 10px;
    transition: background 0.2s;
}
.program-item + .program-item {
    border-top: 1px solid var(--border-soft);
}
.program-item:hover {
    background: var(--excel-bg);
}
.program-num {
    width: 48px;
    height: 48px;
    flex-shrink: 0;
    background: linear-gradient(135deg, var(--excel-green) 0%, var(--excel-green-light) 100%);
    color: #fff;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
}
.program-title {
    font-weight: 600;
    font-size: 1.05rem;
}
.program-meta {
    color: #6c757d;
    font-size: 0.9rem;
}

/* Step cards */
.step-card {
    background: #fff;
    border: 1px solid var(--border-soft);
    border-radius: 14px;
    padding: 2rem;
    text-align: center;
    height: 100%;
    transition: transform 0.2s;
}
.step-card:hover {
    transform: translateY(-3px);
}
.step-num {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--excel-green);
    color: #fff;
    font-weight: 700;
    font-size: 1.25rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

/* CTA card */
.cta-card {
    background: linear-gradient(135deg, var(--excel-green) 0%, var(--excel-green-light) 100%);
    border-radius: 20px;
    padding: 3.5rem;
    box-shadow: 0 25px 50px -12px rgba(29, 111, 66, 0.4);
}

/* Footer */
.footer {
    background: #fafbfc;
    padding: 2.5rem 0;
    border-top: 1px solid var(--border-soft);
}

/* ------- Lessons page ------- */
.lessons-page {
    background: var(--excel-bg);
}

.lessons-hero {
    background: #fff;
    padding: 2.5rem 0 2rem;
    border-bottom: 1px solid var(--border-soft);
}
.lessons-hero h1 {
    letter-spacing: -0.5px;
}
.breadcrumb {
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}
.breadcrumb a {
    color: var(--excel-green);
    text-decoration: none;
}

/* Lesson card */
.lesson-card {
    background: #fff;
    border-radius: 14px;
    overflow: hidden;
    border: 1px solid var(--border-soft);
    height: 100%;
    display: flex;
    flex-direction: column;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.lesson-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 35px rgba(0, 0, 0, 0.08);
}
.lesson-thumb {
    position: relative;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background: #000;
    display: block;
    text-decoration: none;
}
.lesson-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}
.lesson-card:hover .lesson-thumb img {
    transform: scale(1.05);
}
.lesson-thumb-intro {
    background: linear-gradient(135deg, var(--excel-green) 0%, var(--excel-green-light) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
}
.lesson-num {
    position: absolute;
    top: 12px;
    left: 12px;
    background: rgba(0, 0, 0, 0.65);
    color: #fff;
    font-weight: 700;
    font-size: 0.9rem;
    padding: 0.25rem 0.6rem;
    border-radius: 6px;
    backdrop-filter: blur(4px);
    z-index: 2;
}
.lesson-thumb-intro .lesson-num {
    background: rgba(255, 255, 255, 0.2);
}
.play-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.35);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.25s ease;
}
.play-overlay i {
    font-size: 3.5rem;
    color: #fff;
    background: var(--excel-green);
    width: 72px;
    height: 72px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.3);
    transform: scale(0.85);
    transition: transform 0.25s ease;
}
.lesson-card:hover .play-overlay {
    opacity: 1;
}
.lesson-card:hover .play-overlay i {
    transform: scale(1);
}

.lesson-body {
    padding: 1.25rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}
.lesson-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.65rem;
}
.lesson-meta .badge {
    font-weight: 600;
    padding: 0.4rem 0.65rem;
}
.lesson-title {
    font-weight: 700;
    font-size: 1.05rem;
    margin-bottom: 0.5rem;
    line-height: 1.35;
}
.lesson-desc {
    color: #6c757d;
    font-size: 0.9rem;
    margin-bottom: 1rem;
    flex-grow: 1;
}
.lesson-actions {
    display: flex;
    gap: 6px;
    align-items: stretch;
}
.lesson-actions .btn {
    font-weight: 500;
}
.lesson-actions .btn-outline-secondary {
    border-color: var(--border-soft);
    color: #495057;
}
.lesson-actions .btn-outline-secondary:hover {
    background: var(--excel-bg);
    color: var(--excel-green);
    border-color: var(--excel-green);
}

.lesson-card.no-video .lesson-thumb {
    cursor: default;
}

/* Legend */
.legend-card {
    background: #fff;
    border: 1px solid var(--border-soft);
    border-radius: 12px;
    padding: 1.5rem;
}
.legend-card .btn.disabled {
    pointer-events: none;
    opacity: 0.7;
}

/* Responsive tweaks */
@media (max-width: 991px) {
    .hero {
        padding: 3rem 0 4rem;
        text-align: center;
    }
    .hero .stats-row {
        margin-left: auto;
        margin-right: auto;
    }
    .hero .lead {
        margin-left: auto;
        margin-right: auto;
    }
    .hero .d-flex {
        justify-content: center;
    }
    .section-title {
        font-size: 1.85rem;
    }
    .cta-card {
        padding: 2rem;
        text-align: center;
    }
}

@media (max-width: 575px) {
    .hero h1 {
        font-size: 2.25rem;
    }
    .stat-num {
        font-size: 1.4rem;
    }
}