:root {
    --bg: #0a0e17;
    --bg-secondary: #1a2332;
    --bg-hover: #1e293b;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --accent: #3b82f6;
    --border: #2a3448;
    --shadow: rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
    --bg: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-hover: #f1f5f9;
    --text: #0f172a;
    --text-secondary: #475569;
    --accent: #2563eb;
    --border: #e2e8f0;
    --shadow: rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg);
    color: var(--text);
    transition: background 0.3s, color 0.3s;
}

.page {
    display: flex;
    min-height: 100vh;
}

/* ====== SIDEBAR ====== */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    width: 80px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
    padding: 20px 0;
    display: flex;
    flex-direction: column;
    transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    z-index: 1000;
    box-shadow: 4px 0 20px var(--shadow);
}

    .sidebar:hover {
        width: 260px;
    }

        .sidebar:hover .nav-text {
            opacity: 1;
            width: auto;
        }

        .sidebar:hover .language-selector select {
            opacity: 1;
            width: auto;
        }

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--accent);
    padding: 0 24px 20px 24px;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.nav {
    flex: 1;
    padding: 20px 12px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 12px 16px;
    border-radius: 10px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.2s;
    white-space: nowrap;
}

    .nav-link:hover {
        background: var(--bg-hover);
        color: var(--text);
    }

.nav-text {
    opacity: 0;
    width: 0;
    overflow: hidden;
    transition: all 0.3s;
    font-size: 15px;
    font-weight: 500;
}

.language-selector {
    padding: 20px 12px;
    border-top: 1px solid var(--border);
}

    .language-selector select {
        width: 100%;
        padding: 8px;
        background: var(--bg);
        color: var(--text);
        border: 1px solid var(--border);
        border-radius: 8px;
        font-size: 14px;
        cursor: pointer;
        opacity: 0;
        width: 0;
        overflow: hidden;
        transition: all 0.3s;
    }

.sidebar:hover .language-selector select {
    opacity: 1;
    width: auto;
}

/* ====== THEME TOGGLE ====== */
.theme-toggle {
    padding: 10px 12px;
    text-align: center;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 18px;
    transition: all 0.2s;
}

    .theme-toggle:hover {
        color: var(--accent);
    }

/* ====== MAIN CONTENT ====== */
.main-content {
    margin-left: 80px;
    flex: 1;
    padding: 40px;
    max-width: 1200px;
    transition: margin-left 0.3s;
}

.sidebar:hover ~ .main-content {
    margin-left: 260px;
}

/* ====== CARDS ====== */
.card {
    background: var(--bg-secondary);
    padding: 28px 32px;
    border-radius: 16px;
    margin-bottom: 24px;
    border: 1px solid var(--border);
    transition: all 0.3s;
}

    .card:hover {
        border-color: var(--accent);
        transform: translateY(-2px);
        box-shadow: 0 8px 30px var(--shadow);
    }

    .card h3 {
        color: var(--text);
        font-size: 1.3rem;
        margin-bottom: 16px;
    }

    .card p {
        color: var(--text-secondary);
        line-height: 1.7;
    }

    .card strong {
        color: var(--text);
    }

/* ====== TAGS ====== */
.tag-container {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
}

.tag {
    background: var(--bg-hover);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    color: var(--text-secondary);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

    .tag:hover {
        background: var(--accent);
        color: white;
        border-color: var(--accent);
        transform: scale(1.05);
    }

/* ====== TYPOGRAPHY ====== */
h1 {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 8px;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

/* ====== BUTTONS ====== */
.btn {
    display: inline-block;
    background: var(--accent);
    color: white;
    padding: 12px 32px;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

    .btn:hover {
        background: #2563eb;
        transform: translateY(-2px);
        box-shadow: 0 4px 20px rgba(59, 130, 246, 0.3);
    }

.btn-outline {
    background: transparent;
    border: 2px solid var(--accent);
    color: var(--accent);
}

    .btn-outline:hover {
        background: var(--accent);
        color: white;
    }

/* ====== HERO ====== */
.hero {
    padding: 60px 0;
}

    .hero h1 {
        font-size: 4rem;
    }

    .hero .btn-container {
        display: flex;
        gap: 16px;
        margin-top: 24px;
    }

/* ====== PROJECT GRID ====== */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 20px;
}

    .project-grid .card {
        margin-bottom: 0;
    }

/* ====== FORM ====== */
form {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

    form input, form textarea {
        width: 100%;
        padding: 12px 16px;
        background: var(--bg);
        color: var(--text);
        border: 1px solid var(--border);
        border-radius: 10px;
        font-size: 15px;
        outline: none;
        transition: all 0.2s;
        font-family: inherit;
    }

        form input:focus, form textarea:focus {
            border-color: var(--accent);
            box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
        }

    form button {
        background: var(--accent);
        color: white;
        padding: 12px 32px;
        border: none;
        border-radius: 10px;
        font-size: 16px;
        font-weight: 600;
        cursor: pointer;
        transition: all 0.2s;
        align-self: flex-start;
    }

        form button:hover:not(:disabled) {
            background: #2563eb;
            transform: translateY(-2px);
            box-shadow: 0 4px 20px rgba(59, 130, 246, 0.3);
        }

        form button:disabled {
            opacity: 0.6;
            cursor: not-allowed;
        }

/* ====== MESSAGES ====== */
.success-message {
    color: #4ade80;
    padding: 10px;
}

.error-message {
    color: #f87171;
    padding: 10px;
}

/* ====== BURGER MENU (MOBILE) ====== */
.burger-menu {
    display: none;
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 2000;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 10px;
    cursor: pointer;
    color: var(--text);
    font-size: 24px;
}

.mobile-nav {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: var(--bg-secondary);
    z-index: 1500;
    padding: 60px 20px;
    flex-direction: column;
    gap: 16px;
}

    .mobile-nav a {
        color: var(--text);
        text-decoration: none;
        font-size: 24px;
        padding: 12px;
        border-bottom: 1px solid var(--border);
    }

/* ====== MEDIA QUERIES ====== */
@media (max-width: 768px) {
    .sidebar {
        display: none;
    }

    .main-content {
        margin-left: 0;
        padding: 20px;
    }

    .burger-menu {
        display: block;
    }

    .mobile-nav {
        display: flex;
    }
}