:root {
    --bs-primary-rgb: 0, 86, 179; /* 深藍色 #0056B3 */
    --bs-primary: #0056B3;
    --bs-secondary-rgb: 108, 117, 125; /* Bootstrap default gray */
    --bs-secondary: #6c757d;
    --bs-light-rgb: 248, 249, 250;
    --bs-light: #f8f9fa;
    --bs-dark-rgb: 33, 37, 41; /* Bootstrap default dark */
    --bs-dark: #212529;
    --custom-accent: #FFC107; /* 金色點綴 (Bootstrap warning color) */
    --text-dark: #212529;
    --text-light: #f8f9fa;
    --body-bg: #f0f2f5; /* 更淺的灰色背景 */
}

body {
    font-family: 'Noto Sans TC', sans-serif;
    padding-top: 70px; /* Navbar height */
    background-color: var(--body-bg);
    color: var(--text-dark);
    line-height: 1.7;
}

/* Navbar */
.navbar {
    transition: background-color 0.3s ease-in-out;
}
.navbar-brand {
    letter-spacing: 0.5px;
}
.nav-link {
    font-weight: 500;
}
.nav-item .btn-outline-primary {
    border-color: var(--bs-primary);
    color: var(--bs-primary);
    transition: all 0.3s ease;
}
.nav-item .btn-outline-primary:hover,
.nav-item .btn-outline-primary:focus {
    background-color: var(--bs-primary);
    color: var(--text-light);
}
.dropdown-menu-dark .dropdown-item:hover {
    background-color: rgba(255,255,255,0.1);
}

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, var(--bs-primary) 0%, #007bff 100%); /* 主色到亮藍色的漸層 */
    min-height: calc(85vh - 70px); /* 考慮 navbar 高度 */
    padding: 4rem 0;
}
.hero-section h1 {
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}
.hero-section .btn-light {
    color: var(--bs-primary);
    font-weight: 500;
}
.hero-section .btn-lg {
    padding: 0.8rem 2.5rem;
    font-size: 1.1rem;
    border-radius: 50px; /* 圓角按鈕 */
}

/* Section Titles */
.section-title {
    font-weight: 700;
    color: var(--bs-primary);
    margin-bottom: 3rem !important; /* Increased margin */
    position: relative;
    padding-bottom: 1rem; /* Space for the accent line */
}
.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px; /* Wider accent line */
    height: 4px; /* Thicker accent line */
    background-color: var(--custom-accent);
    border-radius: 2px;
}
/* For left-aligned titles on larger screens */
@media (min-width: 992px) {
    .text-lg-start.section-title::after {
        left: 0;
        transform: translateX(0);
    }
}

/* Features Section */
.features-section {
    background-color: var(--bs-light);
}
.feature-item {
    background-color: #ffffff;
    border-radius: 10px; /* Softer corners */
    box-shadow: 0 4px 15px rgba(0,0,0,0.07);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
}
.feature-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
}
.feature-item i {
    color: var(--bs-primary);
    transition: color 0.3s ease;
}
.feature-item:hover i {
    color: var(--custom-accent);
}
.feature-item h3 {
    color: var(--bs-dark);
    margin-top: 1rem;
    margin-bottom: 0.75rem;
    font-weight: 500;
}
.feature-item p {
    font-size: 0.95rem;
    flex-grow: 1;
    margin-bottom: 1.5rem;
}
.feature-item .btn-primary {
    background-color: var(--bs-primary);
    border-color: var(--bs-primary);
    font-weight: 500;
}
.feature-item .btn-primary:hover {
    background-color: #00418a; /* Darker shade of primary */
    border-color: #00418a;
}

/* Founder Section */
.founder-section .founder-img {
    width: 220px; /* Slightly larger image */
    height: 220px;
    object-fit: cover;
    border: 6px solid var(--bs-light); /* Border color matching section background */
    box-shadow: 0 0 0 4px var(--bs-primary), 0 8px 20px rgba(0,0,0,0.15); /* Double border effect + shadow */
}
.founder-section p.lead {
    font-weight: 500;
    color: #495057;
}
.founder-section p {
    font-size: 1.05rem;
    color: #555;
}

/* Past Content Section */
#pastContentSection {
    background-color: var(--body-bg); /* Matches body background */
}
#pastContent iframe {
    width: 100%;
    min-height: 600px; /* Increased height */
    border: none; /* Remove iframe border, rely on container shadow */
    border-radius: 8px; /* Match container rounding */
}
#pastContent {
    min-height: 200px; /* Placeholder height */
    display: flex;
    align-items: center;
    justify-content: center;
}
#pastContentPlaceholder.placeholder-glow .placeholder {
    height: 2em;
    background-color: var(--bs-secondary);
}

/* CTA Section */
.cta-section {
    background: var(--bs-dark) url('./assets/images/cta-background.jpg') no-repeat center center; /* Optional: Add a subtle background pattern or image */
    background-blend-mode: overlay; /* If using image */
    background-color: var(--bs-primary); /* Fallback / primary color */
    background-size: cover;
    position: relative;
}
.cta-section::before { /* Optional: Dark overlay for better text readability if using a light background image */
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    /* background-color: rgba(0, 0, 0, 0.5); */ /* Uncomment if needed */
}
.cta-section .container {
    position: relative; /* Ensure content Gargantuan is above overlay */
    z-index: 1;
}
.cta-section h2 {
    font-weight: 700;
}
.cta-section .btn-warning {
    background-color: var(--custom-accent);
    border-color: var(--custom-accent);
    transition: all 0.3s ease;
    padding: 0.8rem 2.5rem;
}
.cta-section .btn-warning:hover {
    background-color: #e0a800; /* Darker gold */
    border-color: #e0a800;
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

/* Footer */
footer.bg-dark {
    padding-top: 2.5rem;
    padding-bottom: 2.5rem;
}
footer p {
    font-size: 0.95rem;
}

/* Responsive adjustments */
@media (max-width: 991.98px) {
    .hero-section {
        min-height: auto;
        padding: 3rem 0;
    }
    .hero-section h1 {
        font-size: 2.5rem; /* Adjusted for tablets */
    }
    .founder-section .text-lg-start.section-title {
        text-align: center !important;
    }
    .founder-section .text-lg-start.section-title::after {
        left: 50%;
        transform: translateX(-50%);
    }
}

@media (max-width: 767.98px) {
    body {
        padding-top: 63px; /* Adjusted for potentially smaller navbar */
    }
    .hero-section h1 {
        font-size: 2rem;
    }
    .hero-section .lead {
        font-size: 1rem;
    }
    .hero-section .btn-lg {
        font-size: 1rem;
        padding: 0.6rem 1.8rem;
    }
    .section-title {
        font-size: 1.75rem;
        margin-bottom: 2rem !important;
    }
    .section-title::after {
        width: 60px;
        height: 3px;
    }
    .founder-img {
        width: 180px !important;
        height: 180px !important;
    }
    .cta-section h2 {
        font-size: 1.8rem;
    }
    .cta-section .btn-lg {
        font-size: 1rem;
    }
}

/* Custom Button Styles */
.custom-btn {
    border-radius: 50px; /* Matches hero section buttons */
    font-weight: 500;
    padding: 0.8rem 2rem;
    transition: all 0.3s ease;
}

.btn-primary.custom-btn {
    background-color: var(--bs-primary);
    border-color: var(--bs-primary);
    color: var(--text-light);
}

.btn-primary.custom-btn:hover,
.btn-primary.custom-btn:focus {
    background-color: #ffffff; /* Darker shade, consistent with feature-item */
    border-color: #ffffff;
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.btn-outline-primary.custom-btn {
    border-color: var(--bs-primary);
    color: var(--bs-primary);
}

.btn-outline-primary.custom-btn:hover,
.btn-outline-primary.custom-btn:focus {
    background-color: var(--bs-primary);
    border-color: var(--bs-primary);
    color: var(--text-light);
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

/* Responsive adjustments for buttons */
@media (max-width: 767.98px) {
    .custom-btn {
        font-size: 1rem;
        padding: 0.6rem 1.5rem;
    }
}