/* CSS Variables for Theming & Accessibility */
:root {
    /* Dark Theme (Default) */
    --bg-main: #12161a;
    --bg-header: #0d1114;
    --bg-panel: #1c2329;
    --bg-panel-hover: #2c353d;
    --text-main: #ffffff;
    --text-muted: #8a99a6;
    --border-color: #1c2329;
    --accent: #ff9f0a;
    --danger: #ff3b30;
    
    /* Zoom Scale */
    --zoom: 1;
}

[data-theme="light"] {
    --bg-main: #f2f2f7;
    --bg-header: #ffffff;
    --bg-panel: #ffffff;
    --bg-panel-hover: #e5e5ea;
    --text-main: #000000;
    --text-muted: #8e8e93;
    --border-color: #c6c6c8;
    --accent: #ff9f0a;
}

/* General Reset & App Behavior */
* { 
    box-sizing: border-box; 
    margin: 0; 
    padding: 0; 
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; 
    -webkit-user-select: none; 
    user-select: none; 
    -webkit-tap-highlight-color: transparent; 
}
body { 
    background-color: var(--bg-main); 
    color: var(--text-main); 
    overflow: hidden; 
    height: 100dvh; 
    display: flex; 
    flex-direction: column; 
    transition: background-color 0.3s, color 0.3s;
}
#app-container { 
    display: flex; 
    flex-direction: column; 
    flex: 1; 
    min-height: 0; 
    justify-content: space-between; 
}

/* 1. Main Header Styling */
#main-header { 
    background-color: var(--bg-header); 
    display: flex; 
    align-items: center; 
    justify-content: space-between; 
    padding: 10px 15px; 
    border-bottom: 1px solid var(--border-color); 
    height: 56px; 
    transition: background-color 0.3s, border-color 0.3s;
}
#hamburger-btn { 
    background: none; 
    border: none; 
    color: var(--accent); 
    font-size: calc(24px * var(--zoom)); 
    cursor: pointer; 
    padding: 5px; 
}
#header-title-container { 
    display: flex; 
    align-items: center; 
    gap: 8px; 
}
#header-logo { font-size: calc(20px * var(--zoom)); }
#header-title { font-size: calc(15px * var(--zoom)); font-weight: 700; letter-spacing: 0.5px; color: var(--accent); }
.header-spacer { width: 34px; }

/* 2. Side Navigation Drawer */
.side-drawer { 
    position: fixed; top: 0; left: 0; width: 280px; height: 100%; 
    background-color: var(--bg-header); box-shadow: 4px 0 10px rgba(0, 0, 0, 0.5); 
    z-index: 1000; transform: translateX(-100%); transition: transform 0.3s ease-in-out, background-color 0.3s; 
    display: flex; flex-direction: column; 
}
.side-drawer.open { transform: translateX(0); }
.drawer-header { padding: 20px; border-bottom: 1px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
.drawer-header h3 { font-size: calc(18px * var(--zoom)); color: var(--accent); }
.close-btn { font-size: calc(28px * var(--zoom)); cursor: pointer; color: var(--text-muted); }
.drawer-links { list-style: none; padding: 10px 0; }
.drawer-links li a { display: block; padding: 15px 20px; color: var(--text-main); text-decoration: none; font-size: calc(15px * var(--zoom)); border-bottom: 1px solid var(--bg-main); transition: background 0.2s; }
.drawer-links li a:active { background-color: var(--bg-panel); }

/* 3. Category Bar */
#category-bar { display: flex; padding: 10px; gap: 10px; background-color: var(--bg-main); transition: background-color 0.3s; }
.category-btn { flex: 1; background-color: var(--bg-panel); border: 1px solid var(--border-color); padding: 10px 0; font-size: calc(13px * var(--zoom)); font-weight: 600; border-radius: 6px; cursor: pointer; text-align: center; transition: all 0.2s; }

#btn-fiat { color: #85bb65; border-color: #85bb65; }
#btn-fiat:active { background-color: #85bb65; color: #0d1114; }

#btn-crypto { color: #f2a900; border-color: #f2a900; }
#btn-crypto:active { background-color: #f2a900; color: #0d1114; }

/* 4. Currency List Rows */
#currency-list { flex: 1; min-height: 0; overflow-y: auto; padding: 5px; display: flex; flex-direction: column; }
.currency-row { display: flex; justify-content: space-between; align-items: center; padding: 14px 10px; border-bottom: 1px solid var(--border-color); background-color: transparent; transition: background-color 0.2s; cursor: pointer; }
.currency-row.active-input { background-color: var(--bg-panel); border-left: 3px solid var(--accent); }
.left-block { display: flex; align-items: center; gap: 12px; }
.currency-icon { width: 28px; height: 28px; border-radius: 50%; object-fit: cover; }
.currency-info { display: flex; flex-direction: column; }
.currency-code { font-weight: 700; font-size: calc(14px * var(--zoom)); letter-spacing: 0.5px; color: var(--text-main); }
.currency-fullname { font-size: calc(12px * var(--zoom)); color: var(--text-muted); margin-top: 2px; }
.right-block { display: flex; flex-direction: column; align-items: flex-end; justify-content: center; flex: 1; padding-left: 15px; }
.currency-value { font-size: calc(22px * var(--zoom)); font-weight: 500; color: var(--text-main); word-break: break-all; text-align: right; display: flex; align-items: center; }

/* Empty State Layout */
.empty-state { flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; padding: 40px 30px; color: var(--text-muted); }
.empty-state-icon { width: calc(64px * var(--zoom)); height: calc(64px * var(--zoom)); margin-bottom: 16px; cursor: pointer; object-fit: contain; transition: transform 0.1s; }
.empty-state-icon:active { transform: scale(0.95); }
.empty-state-title { font-size: calc(16px * var(--zoom)); font-weight: 700; color: var(--text-main); margin-bottom: 8px; letter-spacing: 0.3px; }
.empty-state-text { font-size: calc(13px * var(--zoom)); line-height: 1.6; max-width: 260px; color: var(--text-muted); }
.empty-state-text strong { color: var(--text-main); }

/* 5. Status Bar */
#status-bar { background-color: var(--bg-header); display: flex; justify-content: center; align-items: center; gap: 8px; padding: 8px 0; font-size: calc(11px * var(--zoom)); color: var(--text-muted); border-top: 1px solid var(--border-color); letter-spacing: 0.3px; position: relative; transition: background-color 0.3s; }
#expand-keypad-btn { background: none; border: none; color: var(--accent); font-size: calc(14px * var(--zoom)); font-weight: 700; cursor: pointer; padding: 2px 8px; display: none; position: absolute; right: 15px; }
#timestamp { font-weight: 600; color: var(--text-main); margin-left: 4px; }

/* 6. Keypad Grid Layout */
#keypad { 
    background-color: var(--bg-header); 
    display: grid; 
    grid-template-columns: repeat(5, 1fr); 
    grid-gap: 1px; 
    padding-bottom: env(safe-area-inset-bottom); 
    transition: max-height 0.3s ease-out, background-color 0.3s; 
    max-height: 600px; 
    flex-shrink: 0; 
    z-index: 10;
}
#keypad.hidden { max-height: 0; overflow: hidden; }
.key { background-color: var(--bg-header); border: none; color: var(--text-main); font-size: calc(24px * var(--zoom)); padding: 16px 0; cursor: pointer; display: flex; justify-content: center; align-items: center; font-weight: 400; transition: background-color 0.2s; }
.key:active { background-color: var(--bg-panel); }
.operator-key, .action-key { color: var(--accent); font-weight: 600; }

/* 7. Modal Overlay Layout */
.modal-overlay { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background-color: rgba(0, 0, 0, 0.85); z-index: 2000; display: none; justify-content: center; align-items: flex-end; }
.modal-overlay.open { display: flex; }
.modal-content { background-color: var(--bg-header); width: 100%; height: 85vh; border-top-left-radius: 16px; border-top-right-radius: 16px; display: flex; flex-direction: column; overflow: hidden; transition: background-color 0.3s; }
.modal-header { padding: 15px 20px; border-bottom: 1px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
#modal-title { font-size: calc(16px * var(--zoom)); font-weight: 700; color: var(--text-main); }
.modal-close { font-size: calc(28px * var(--zoom)); cursor: pointer; color: var(--text-muted); }
#modal-search { width: calc(100% - 40px); margin: 0 20px 10px 20px; padding: 10px; background-color: var(--bg-panel); border: 1px solid var(--border-color); color: var(--text-main); border-radius: 6px; font-size: calc(14px * var(--zoom)); }
#modal-list { flex: 1; overflow-y: auto; padding: 10px; }
.modal-row { display: flex; justify-content: space-between; align-items: center; padding: 12px 10px; border-bottom: 1px solid var(--border-color); }
.modal-add-btn { background-color: var(--bg-panel); border: 1px solid var(--accent); color: var(--accent); width: 32px; height: 32px; border-radius: 50%; font-size: 18px; font-weight: 600; display: flex; justify-content: center; align-items: center; cursor: pointer; transition: all 0.2s; }
.modal-row.selected { background-color: var(--bg-panel-hover) !important; border-left: 3px solid var(--accent); }
.modal-row.selected .modal-add-btn { background-color: var(--accent); color: #0d1114; }
.modal-row.selected .modal-add-btn::after { content: '✓'; }
.modal-row .modal-add-btn::after { content: '+'; }

/* 8. Menu Pages Overlay */
.menu-page-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-color: var(--bg-main); z-index: 3000;
    transform: translateX(100%); transition: transform 0.3s ease-in-out, background-color 0.3s;
    display: flex; flex-direction: column;
}
.menu-page-overlay.open { transform: translateX(0); }
.page-header {
    background-color: var(--bg-header); display: flex; align-items: center; justify-content: space-between;
    padding: 10px 15px; border-bottom: 1px solid var(--border-color); height: 56px; transition: background-color 0.3s;
}
.page-header h2 { font-size: calc(16px * var(--zoom)); font-weight: 700; color: var(--text-main); }
.back-btn { background: none; border: none; color: var(--accent); font-size: calc(24px * var(--zoom)); cursor: pointer; padding: 0 10px 0 0; }
.page-content { flex: 1; overflow-y: auto; padding: 20px; color: var(--text-main); font-size: calc(14px * var(--zoom)); line-height: 1.6; padding-bottom: env(safe-area-inset-bottom); }

/* Settings UI Elements */
.setting-group { margin-bottom: 25px; }
.setting-group-title { font-size: calc(12px * var(--zoom)); color: var(--text-muted); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 10px; font-weight: 600; }
.setting-card { background-color: var(--bg-panel); border-radius: 10px; overflow: hidden; border: 1px solid var(--border-color); }
.setting-row { display: flex; justify-content: space-between; align-items: center; padding: 15px; border-bottom: 1px solid var(--border-color); cursor: pointer; transition: background-color 0.2s; }
.setting-row:last-child { border-bottom: none; }
.setting-row:active { background-color: var(--bg-panel-hover); }
.setting-label { font-size: calc(15px * var(--zoom)); color: var(--text-main); font-weight: 500; }
.setting-value { color: var(--text-muted); font-size: calc(14px * var(--zoom)); display: flex; align-items: center; gap: 5px; }
.setting-value::after { content: '›'; font-size: 18px; margin-left: 5px; margin-bottom: 2px; }

.version-text { text-align: center; margin-top: 30px; font-size: calc(13px * var(--zoom)); color: var(--text-muted); }
.version-text span { color: var(--danger); font-weight: bold; }

/* Sub-modals for Settings Options */
.option-row { display: flex; justify-content: space-between; align-items: center; padding: 15px; border-bottom: 1px solid var(--border-color); cursor: pointer; }
.option-row.selected { color: var(--accent); font-weight: bold; }
.option-row.selected::after { content: '✓'; color: var(--accent); font-size: 18px; }