:root {
    --primary-color: #d6336c; 
    --bg-color: #fff0f3; 
    --container-bg: #ffffff;
    --text-color: #333333;
    --input-border: #ddd;
    --input-bg: #ffffff;
}

body.dark-mode {
    --bg-color: #1a1a2e;
    --container-bg: #16213e;
    --text-color: #f1f1f1;
    --input-border: #4a4e69;
    --input-bg: #22223b;
}

body {
    margin: 0; background-color: var(--bg-color); color: var(--text-color);
    font-family: 'Poppins', sans-serif; display: flex;
    justify-content: center; align-items: center; min-height: 100vh;
    transition: 0.4s; overflow-x: hidden;
}

.theme-toggle {
    position: absolute; top: 20px; right: 20px; background: var(--container-bg);
    color: var(--text-color); border: 1px solid var(--input-border);
    padding: 8px 16px; border-radius: 20px; cursor: pointer; z-index: 1000;
}

.container {
    background-color: var(--container-bg); width: 90%; max-width: 600px;
    padding: 2rem; border-radius: 15px; box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    margin: 60px 0 20px 0; z-index: 10;
}

h1, h2 { font-family: 'Playfair Display', serif; color: var(--primary-color); text-align: center; }

.input-group { margin-bottom: 1rem; }
.input-group label { display: block; font-size: 0.9rem; margin-bottom: 5px; }
.input-group input:not([type="color"]), .input-group select {
    width: 100%; padding: 10px; border: 1px solid var(--input-border);
    border-radius: 8px; background: var(--input-bg); color: var(--text-color); box-sizing: border-box;
}

.input-group textarea {
    width: 100%; padding: 10px; border: 1px solid var(--input-border);
    border-radius: 8px; background: var(--input-bg); color: var(--text-color); box-sizing: border-box;
    font-family: 'Poppins', sans-serif; resize: vertical;
}

#charCounter { display: block; text-align: right; font-size: 0.8rem; margin-top: 4px; }

.content-choice {
    display: flex;
    gap: 20px;
    margin-top: 5px;
}
.content-choice label {
    display: flex;
    align-items: center;
    gap: 5px;
    cursor: pointer;
}
.design-options { display: flex; gap: 15px; background: rgba(214, 51, 108, 0.05); padding: 15px; border-radius: 8px; }

/* Gelişmiş Ayarlar Menüsü */
.advanced-settings { margin-top: 10px; padding: 10px; border: 1px dashed var(--primary-color); border-radius: 8px; }
.advanced-settings summary { cursor: pointer; font-weight: 500; color: var(--primary-color); list-style: none; text-align: center;}
.advanced-content { margin-top: 15px; }

button { width: 100%; padding: 12px; border: none; border-radius: 8px; cursor: pointer; font-weight: bold; }
.btn-primary { background: var(--primary-color); color: white; }
.btn-secondary { background: var(--input-bg); color: var(--text-color); border: 1px solid var(--input-border); flex:1;}

.letter-paper {
    background: #fdfbf7; padding: 30px; border: 1px solid #eee; border-radius: 8px;
    font-size: 1.2rem; line-height: 1.8; color: #333; margin-bottom: 1.5rem;
}

#letterImage { max-width: 100%; border-radius: 10px; margin-bottom: 15px; box-shadow: 0 4px 8px rgba(0,0,0,0.1); }
.actions { display: flex; gap: 10px; }
.hidden { display: none !important; }

/* YENİ: ZARF VE ŞİFRE EKRANI STİLLERİ */
.overlay-screen {
    position: fixed; top: 0; left: 0; width: 100vw; height: 100vh;
    background: var(--bg-color); z-index: 500; display: flex;
    flex-direction: column; justify-content: center; align-items: center;
}

#pinBox { background: var(--container-bg); padding: 2rem; border-radius: 15px; text-align: center; box-shadow: 0 10px 30px rgba(0,0,0,0.1); }
#pinBox input { font-size: 2rem; text-align: center; letter-spacing: 10px; margin-bottom: 15px; }
.error-text { color: red; font-size: 0.9rem; margin-top: 10px; }

/* Zarf Tasarımı */
.envelope {
    position: relative; width: 300px; height: 200px; background: #e0b0b0;
    margin-top: 20px; border-radius: 0 0 10px 10px; cursor: pointer;
    box-shadow: 0 15px 35px rgba(0,0,0,0.2); transition: transform 0.3s;
}
.envelope:hover { transform: translateY(-10px); }
.flap {
    position: absolute; top: 0; left: 0; width: 0; height: 0;
    border-left: 150px solid transparent; border-right: 150px solid transparent;
    border-top: 100px solid #d49c9c; z-index: 3; transition: transform 0.8s ease; transform-origin: top;
}
.envelope::before { /* Zarfın Alt Kısmı */
    content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 0;
    border-left: 150px solid transparent; border-right: 150px solid transparent;
    border-bottom: 100px solid #c98888; z-index: 2;
}
.seal {
    position: absolute; top: 80px; left: 50%; transform: translateX(-50%);
    width: 120px; background: #900; color: white; text-align: center;
    border-radius: 20px; padding: 5px; font-size: 0.8rem; z-index: 4; font-weight: bold;
}
.envelope.open .flap { transform: rotateX(180deg); z-index: 1;}
.envelope.open .seal { opacity: 0; transition: 0.2s;}