.portfolio-container {
    width: 100%;
    max-width: 80rem; 
    margin-left: auto;
    margin-right: auto;
    padding-left: 1.5rem;
    padding-right: 1.5rem;
}

.section-padding { 
    padding: 4.5rem 1.5rem 6rem;
    background-color: transparent;
}

#hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.section-bg { 
    background-color: var(--color-bg-secondary);
    transition: background-color 0.3s ease; 
}

.dark .section-bg { 
    background-color: #0a0a0a; 
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.55rem 1.25rem;
    font-size: 0.85rem;
    font-weight: 500;
    border-radius: 0.5rem;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: opacity 0.15s ease, transform 0.15s ease;
    box-shadow: none;
}

.btn-primary {
    background-color: #1d1d1f;
    color: #ffffff;
    letter-spacing: -0.01em;
}
.btn-primary:hover {
    background-color: #000000;
    opacity: 1;
    transform: none;
}
.dark .btn-primary {
    background-color: #f5f5f7;
    color: #1d1d1f;
}
.dark .btn-primary:hover {
    background-color: #ffffff;
}

.btn-primary.btn-download { gap: 0.5rem; }

/* Header & Nav */
#header {
    width: 100%; position: sticky; top: 0; z-index: 50;
    background-color: var(--color-header-bg);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 0.5px solid var(--color-border-subtle);
    transition: background-color 0.3s ease, box-shadow 0.3s ease; 
}

#header.scrolled {
    box-shadow: none;
}

.header-content { display: flex; align-items: center; justify-content: space-between; height: 5rem; }

.logo {
    font-size: 1.5rem; font-weight: 800; color: var(--color-text-primary);
    cursor: pointer; transition: color 0.3s ease; 
}
.dark .logo { color: var(--color-text-primary); }
.logo:hover { color: var(--color-indigo-700); }
.dark .logo:hover { color: var(--color-white); }
.logo:hover .text-indigo { color: var(--color-indigo-700); transition: color 0.3s ease; }
.dark .logo:hover .text-indigo { color: var(--color-white); }

#desktop-nav { display: none; align-items: center; font-weight: 500; margin-right: 2rem; gap: 1.5rem; }

.nav-item { 
    color: var(--color-text-secondary); 
    text-decoration: none; 
    transition: color 0.2s ease, border-color 0.2s ease; 
    padding-bottom: 0.25rem;
    border-bottom: 2px solid transparent;
}
.nav-item:hover { color: var(--color-text-primary); }

.nav-item.active {
    color: var(--color-text-primary);
    border-bottom: 1.5px solid var(--color-text-primary);
}
.dark .nav-item.active {
    color: var(--color-text-primary);
    border-bottom: 1.5px solid var(--color-text-primary);
}

.theme-toggle-btn, .mobile-menu-btn {
    padding: 0.5rem; border-radius: 9999px; color: var(--color-gray-700);
    background-color: transparent; border: none; cursor: pointer;
    transition: background-color 0.2s ease, color 0.2s ease;
}
.mobile-menu-btn { display: block; border-radius: 0.5rem; }
.theme-toggle-btn:hover, .mobile-menu-btn:hover { background-color: var(--color-gray-200); }
.dark .theme-toggle-btn, .dark .mobile-menu-btn { color: var(--color-gray-300); }
.dark .theme-toggle-btn:hover, .dark .mobile-menu-btn:hover { background-color: var(--color-gray-700); }

/* Mobile Menu */
.mobile-menu-dropdown {
    position: absolute; top: 5rem; left: 0; right: 0; z-index: 40; 
    background-color: var(--color-white);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.06);
    border-top: none; transition: background-color 0.3s ease, border-color 0.3s ease;
}
.dark .mobile-menu-dropdown { background-color: var(--color-gray-800); border-top: none; }
.mobile-nav-list { display: flex; flex-direction: column; padding: 1rem; gap: 0.5rem; }
.mobile-nav-item {
    width: 100%; text-align: left; padding: 0.5rem 0.75rem; color: var(--color-gray-700);
    border-radius: 0.5rem; text-decoration: none; 
    transition: background-color 0.2s ease, color 0.2s ease;
}
.dark .mobile-nav-item { color: var(--color-gray-200); }
.mobile-nav-item:hover { background-color: #eef2ff; }
.dark .mobile-nav-item:hover { background-color: var(--color-gray-700); }

/* Footer */
.main-footer {
    padding: 1.5rem 0; background-color: var(--color-bg-secondary);
    border-top: 0.5px solid var(--color-border-subtle);
    text-align: center; transition: background-color 0.3s ease;
}
.footer-content { font-size: 0.875rem; color: var(--color-text-secondary); }

/* Modals */
.modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-color: rgba(0, 0, 0, 0.5); display: flex; justify-content: center;
    align-items: center; z-index: 100;
}
.modal-content {
    position: relative; background-color: var(--color-bg-primary);
    color: var(--color-text-primary); padding: 2rem; border-radius: 0.75rem;
    max-width: 90%; width: 28rem; box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    text-align: center;
}
.modal-title { font-size: 1.5rem; font-weight: 700; margin-bottom: 0.5rem; }
.modal-text { color: var(--color-text-secondary); margin-bottom: 1.5rem; }
.btn-modal-close {
    width: 100%; padding: 0.5rem 1rem; border-radius: 0.5rem; font-weight: 600;
    background-color: var(--color-indigo-600); color: var(--color-white); box-shadow: none;
}
.btn-modal-close:hover { background-color: var(--color-indigo-700); transform: none; }
.modal-close-btn {
    position: absolute; top: 0.5rem; right: 0.75rem; background: none; border: none;
    font-size: 2rem; font-weight: 300; color: var(--color-gray-600);
    cursor: pointer; padding: 0.25rem; line-height: 1; transition: color 0.2s; z-index: 10;
}
.modal-close-btn:hover { color: var(--color-red-500); }