/* TAFA Renk Paleti */
:root {
    --primary: #ffb717; 
    --bg-color: #f8f9fa; 
    --card-bg: #ffffff; 
    --text-dark: #111111; 
    --text-light: #555555; 
    --header-bg: #ffffff; 
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-dark);
    margin: 0;
    padding: 0; 
}

/* --- ŞİFRE EKRANI --- */
#login-screen {
    position: fixed; top: 0; left: 0; width: 100%; height: 100vh;
    background-color: var(--bg-color);
    display: flex; justify-content: center; align-items: center; z-index: 9999;
}
.login-box {
    background: var(--card-bg); padding: 40px; border-radius: 8px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1); text-align: center;
    width: 100%; max-width: 350px; border-top: 5px solid var(--primary);
}
.login-box img { max-height: 70px; margin-bottom: 20px; }
.login-box h2 { margin-top: 0; font-size: 1.2rem; color: var(--text-dark); margin-bottom: 20px; }
.login-box input {
    width: 90%; padding: 12px; margin-bottom: 15px; border: 1px solid #ccc;
    border-radius: 4px; font-size: 1rem; outline: none; transition: border-color 0.2s;
}
.login-box input:focus { border-color: var(--primary); }
.login-box button {
    width: 100%; padding: 12px; background-color: var(--primary); color: var(--text-dark);
    border: none; border-radius: 4px; font-size: 1rem; font-weight: bold;
    cursor: pointer; transition: background-color 0.2s;
}
.login-box button:hover { background-color: #e6a414; }
#error-msg { color: #d9534f; font-size: 0.9rem; margin-top: 10px; display: none; }

/* --- ANA UYGULAMA İÇERİĞİ --- */
#app-content { display: none; }
header {
    background-color: var(--header-bg); text-align: center; padding: 30px 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08); margin-bottom: 40px; border-bottom: 5px solid var(--primary); 
}
header img { max-width: 100%; height: auto; max-height: 120px; object-fit: contain; }
.header-subtitle { margin: 15px 0 0 0; font-size: 1rem; color: var(--text-light); }
.header-subtitle strong { color: var(--text-dark); font-weight: 600; }
.badge {
    display: inline-block; margin-left: 8px; padding: 4px 10px; background-color: var(--primary);
    color: var(--text-dark); border-radius: 20px; font-size: 0.75rem; font-weight: bold;
    text-transform: uppercase; vertical-align: middle; box-shadow: 0 2px 4px rgba(255, 183, 23, 0.3);
}
.container { padding: 0 20px 40px 20px; max-width: 1200px; margin: 0 auto; }
.grid-container { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px; }
.subject-card {
    background: var(--card-bg); border-radius: 6px; padding: 20px; box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    cursor: pointer; transition: all 0.3s ease; border-left: 5px solid var(--text-dark); 
    border-top: 1px solid #eee; border-right: 1px solid #eee; border-bottom: 1px solid #eee;
}
.subject-card:hover { transform: translateY(-4px); box-shadow: 0 10px 20px rgba(0,0,0,0.08); border-left-color: var(--primary); }
.subject-card h3 { margin: 0; font-size: 1.15rem; display: flex; justify-content: space-between; align-items: center; color: var(--text-dark); }
.subject-card h3 span { font-size: 0.8rem; color: var(--text-light); transition: transform 0.3s ease; }
.subject-card.active-card h3 span { transform: rotate(180deg); color: var(--primary); }

.app-list { display: none; list-style-type: none; padding: 0; margin-top: 15px; border-top: 1px solid #f0f0f0; padding-top: 15px; }
.app-list.active { display: block; animation: fadeIn 0.3s ease-in-out; }
.app-list li a {
    display: block; padding: 12px 15px; background: var(--bg-color); color: var(--text-dark);
    text-decoration: none; border-radius: 4px; margin-bottom: 8px; font-size: 0.95rem;
    font-weight: 500; transition: all 0.2s ease; border-left: 3px solid transparent;
}
.app-list li a:hover { background: var(--primary); color: var(--text-dark); border-left: 3px solid var(--text-dark); padding-left: 20px; }
.empty-list { font-size: 0.85rem; color: var(--text-light); font-style: italic; padding-left: 10px; }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Giriş Ekranı Alt Bilgi */
.login-footer {
    margin-top: 25px;
    font-size: 0.85rem;
    color: var(--text-light);
    border-top: 1px solid #eee;
    padding-top: 15px;
}
.login-footer strong {
    color: var(--text-dark);
}