/* =============================================
   HABIBUR RAHMAN PORTFOLIO - MAIN STYLES
   Dark Theme CSS Framework
   ============================================= */

/* CSS Variables */
:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --accent-primary: #58a6ff;
    --accent-secondary: #7ee787;
    --accent-purple: #a371f7;
    --accent-pink: #db61a2;
    --accent-orange: #f0883e;
    --accent-red: #f85149;
    --border-color: #30363d;
    --gradient-start: #58a6ff;
    --gradient-end: #a371f7;

    /* Platform colors */
    --github-color: #fff;
    --medium-color: #00ab6c;
    --linkedin-color: #0a66c2;
    --youtube-color: #ff0000;
}

/* Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Base body styles */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
}

/* =============================================
   ANIMATED BACKGROUND
   ============================================= */
.bg-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.bg-animation::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 20% 80%, rgba(88, 166, 255, 0.08) 0%, transparent 50%),
                radial-gradient(circle at 80% 20%, rgba(163, 113, 247, 0.08) 0%, transparent 50%),
                radial-gradient(circle at 40% 40%, rgba(126, 231, 135, 0.05) 0%, transparent 40%);
    animation: float 20s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    33% { transform: translate(30px, -30px) rotate(5deg); }
    66% { transform: translate(-20px, 20px) rotate(-5deg); }
}

/* =============================================
   NAVIGATION
   ============================================= */
.navbar {
    background: rgba(22, 27, 34, 0.85) !important;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    transition: all 0.3s ease;
}

.navbar-brand img {
    height: 50px;
    filter: brightness(1.1);
    transition: transform 0.3s ease;
}

.navbar-brand:hover img {
    transform: scale(1.05);
}

.navbar-nav .nav-link {
    color: var(--text-secondary) !important;
    font-weight: 500;
    padding: 0.5rem 1rem !important;
    margin: 0 0.25rem;
    border-radius: 8px;
    transition: all 0.3s ease;
    position: relative;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.navbar-nav .nav-link i {
    font-size: 0.9rem;
    opacity: 0.7;
    transition: all 0.3s ease;
}

.navbar-nav .nav-link:hover {
    color: var(--text-primary) !important;
    background: var(--bg-tertiary);
}

.navbar-nav .nav-link:hover i {
    opacity: 1;
}

/* Active navigation link */
.navbar-nav .nav-link.active {
    color: var(--accent-primary) !important;
    background: rgba(88, 166, 255, 0.1);
}

.navbar-nav .nav-link.active i {
    opacity: 1;
    color: var(--accent-primary);
}

.navbar-nav .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--gradient-start), var(--gradient-end));
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.navbar-nav .nav-link:hover::after {
    width: 60%;
}

.navbar-nav .nav-link.active::after {
    width: 80%;
}

.navbar-toggler {
    border-color: var(--border-color);
    background: var(--bg-tertiary);
    padding: 0.5rem 0.75rem;
}

.navbar-toggler:focus {
    box-shadow: none;
    outline: none;
}

.navbar-toggler-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
}

.navbar-toggler-icon i {
    color: var(--text-primary);
    font-size: 1.25rem;
}

/* Mobile nav dropdown */
@media (max-width: 991px) {
    .navbar-collapse {
        background: var(--bg-secondary);
        border-radius: 12px;
        margin-top: 1rem;
        padding: 1rem;
        border: 1px solid var(--border-color);
    }

    .navbar-nav .nav-link {
        padding: 0.75rem 1rem !important;
        margin: 0.25rem 0;
    }

    .navbar-nav .nav-link.active::after {
        width: 0;
    }

    .navbar-nav .nav-link.active {
        border-left: 3px solid var(--accent-primary);
        border-radius: 0 8px 8px 0;
    }
}

/* =============================================
   MAIN CONTENT
   ============================================= */
.main-content {
    padding-top: 120px;
    min-height: 100vh;
}

/* =============================================
   PAGE HEADER
   ============================================= */
.page-header {
    text-align: center;
    margin-bottom: 4rem;
}

.page-title {
    font-size: 2.75rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1rem;
}

.page-title.green {
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-title.purple {
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-purple) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-title.pink {
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-pink) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-title.red {
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-red) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    max-width: 700px;
    margin: 0 auto;
}

/* =============================================
   SECTION HEADER
   ============================================= */
.section-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 3rem 0 2rem;
}

.section-header h2 {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.section-header::after {
    content: '';
    flex: 1;
    height: 1px;
    background: linear-gradient(90deg, var(--border-color), transparent);
}

.section-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    font-size: 1.2rem;
    color: white;
}

.section-icon.blue {
    background: linear-gradient(135deg, var(--accent-primary), #1f6feb);
}

.section-icon.green {
    background: linear-gradient(135deg, var(--accent-secondary), #2ea043);
}

.section-icon.purple {
    background: linear-gradient(135deg, var(--accent-purple), #8b5cf6);
}

.section-icon.pink {
    background: linear-gradient(135deg, var(--accent-pink), #bf4b8a);
}

.section-icon.red {
    background: linear-gradient(135deg, var(--accent-red), var(--accent-orange));
}

/* =============================================
   CARDS - BASE STYLES
   ============================================= */
.card-base {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    transition: all 0.3s ease;
    overflow: hidden;
}

.card-base:hover {
    border-color: var(--accent-primary);
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
}

/* Card with left accent border */
.card-accent {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.card-accent::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--accent-primary), var(--accent-purple));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.card-accent:hover {
    border-color: var(--accent-primary);
    transform: translateX(5px);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.card-accent:hover::before {
    opacity: 1;
}

/* =============================================
   BUTTONS & LINKS
   ============================================= */
.btn-primary-custom {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1.25rem;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-purple));
    border: none;
    border-radius: 10px;
    color: white;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s ease;
}

.btn-primary-custom:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(88, 166, 255, 0.3);
    color: white;
    text-decoration: none;
}

.link-arrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    background: rgba(88, 166, 255, 0.1);
    border-radius: 8px;
    transition: all 0.3s ease;
}

.link-arrow:hover {
    background: rgba(88, 166, 255, 0.2);
    color: var(--accent-primary);
    text-decoration: none;
    transform: translateX(5px);
}

.link-arrow i {
    transition: transform 0.3s ease;
}

.link-arrow:hover i {
    transform: translateX(3px);
}

/* =============================================
   BADGES
   ============================================= */
.badge-status {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-status.green {
    background: rgba(126, 231, 135, 0.15);
    color: var(--accent-secondary);
}

.badge-status.blue {
    background: rgba(88, 166, 255, 0.15);
    color: var(--accent-primary);
}

.badge-status.purple {
    background: rgba(163, 113, 247, 0.15);
    color: var(--accent-purple);
}

.badge-status.red {
    background: rgba(248, 81, 73, 0.15);
    color: var(--accent-red);
}

.badge-status.pulse::before {
    content: '';
    width: 6px;
    height: 6px;
    background: currentColor;
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* =============================================
   FOOTER
   ============================================= */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    text-align: center;
    margin-top: 4rem;
}

.footer p {
    color: var(--text-muted);
    margin: 0;
    font-size: 0.9rem;
}

/* =============================================
   UTILITY CLASSES
   ============================================= */
.text-primary-custom { color: var(--text-primary); }
.text-secondary-custom { color: var(--text-secondary); }
.text-muted-custom { color: var(--text-muted); }
.text-accent { color: var(--accent-primary); }
.text-green { color: var(--accent-secondary); }
.text-purple { color: var(--accent-purple); }
.text-pink { color: var(--accent-pink); }
.text-orange { color: var(--accent-orange); }
.text-red { color: var(--accent-red); }

.bg-primary-custom { background-color: var(--bg-primary); }
.bg-secondary-custom { background-color: var(--bg-secondary); }
.bg-tertiary-custom { background-color: var(--bg-tertiary); }

.border-custom { border-color: var(--border-color); }

/* Divider */
.section-divider {
    border: none;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--border-color), transparent);
    margin: 4rem 0;
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

/* Loading spinner */
.loading {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* =============================================
   SCROLLBAR
   ============================================= */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border-color);
}

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 991px) {
    .main-content {
        padding-top: 100px;
    }
}

@media (max-width: 768px) {
    .page-title {
        font-size: 2rem;
    }

    .section-header h2 {
        font-size: 1.5rem;
    }
}

@media (max-width: 576px) {
    .page-title {
        font-size: 1.75rem;
    }

    .navbar {
        padding: 0.75rem 1rem;
    }
}