/* --- Variables (Theming Ready) --- */
:root {
  /* Base Hue (Default: Lively Green) */
  --hue: 174;

  /* Generate Colors from Hue */
  --primary-sat: 50%; --primary-lig: 60%;
  --success-sat: 45%; --success-lig: 80%;
  --warning-sat: 100%; --warning-lig: 71%;
  --danger-sat: 100%; --danger-lig: 70%;

  --primary:   hsl(var(--hue), var(--primary-sat), var(--primary-lig));
  --success:   hsl(calc(var(--hue) - 20), var(--success-sat), var(--success-lig));
  --warning:   hsl(50, var(--warning-sat), var(--warning-lig));
  --danger:    hsl(0, var(--danger-sat), var(--danger-lig));

  /* Text and Glass */
  --text-base-lig: 20%;
  --text:      hsl(var(--hue), 10%, var(--text-base-lig));
  --text-light: hsl(var(--hue), 10%, calc(var(--text-base-lig) + 30%));

  --glass-lightness: 95%;
  --glass-alpha: 0.1;
  --glass-bg:  hsla(var(--hue), 20%, var(--glass-lightness), var(--glass-alpha));
  --glass-bg-header: hsla(var(--hue), 20%, var(--glass-lightness), calc(var(--glass-alpha) - 0.02));
  --glass-bg-content: hsla(var(--hue), 20%, var(--glass-lightness), calc(var(--glass-alpha) + 0.03));
  --glass-bg-card: hsla(var(--hue), 20%, var(--glass-lightness), calc(var(--glass-alpha) - 0.04)); /* Base for gradient */
  --glass-border: hsla(var(--hue), 15%, calc(var(--glass-lightness) - 5%), 0.15);
  --glass-border-light: hsla(var(--hue), 15%, calc(var(--glass-lightness) - 5%), 0.08);

  /* Other variables */
  --blur-intensity: 8px;
  --border-radius: 12px;
  --shadow-md: 0 8px 32px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 10%), 0.08);
  --shadow-sm: 0 4px 16px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 10%), 0.05);
  --scrollbar-width: 6px;
  --theme-transition-duration: 0.4s;
}

/* Dark Mode Auto-Switching */
@media (prefers-color-scheme: dark) {
  :root {
    --hue: 210; /* Default dark hue (Blueish) */
    --text-base-lig: 85%;
    --glass-lightness: 20%;
    --glass-alpha: 0.12;
    --shadow-md: 0 8px 32px hsla(var(--hue), 50%, 5%, 0.15);
    --shadow-sm: 0 4px 16px hsla(var(--hue), 50%, 5%, 0.1);
  }
}

/* --- Global Styles & Dynamic Background --- */
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: "LXGW WenKai Screen", sans-serif !important;
    line-height: 1.6; min-height: 100vh; display: flex; flex-direction: column;
    background: url('https://r2tuchuang.989458.xyz/PicGo/QQ_1745046009267_upscayl_2x_upscayl-lite-4x.png') center/cover fixed;
    position: relative; color: var(--text); text-rendering: optimizeLegibility; padding: 20px;
    transition: color var(--theme-transition-duration) ease, background-color var(--theme-transition-duration) ease;
    overflow-x: hidden; /* Prevent horizontal scrollbar from gradient */
}
/* Dynamic background */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: linear-gradient(125deg, hsla(var(--hue), 45%, 70%, 0.08), hsla(calc(var(--hue) + 60), 45%, 70%, 0.04));
  background-size: 200% 200%;
  animation: gradientMove 18s ease infinite;
  z-index: -1;
  transition: background var(--theme-transition-duration) ease;
}
@keyframes gradientMove {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Ensure external UI elements don't get unwanted backdrop filter */
#waifu, .js-cursor-container { backdrop-filter: none !important; -webkit-backdrop-filter: none !important; }

.container {
    flex: 1; width: 95%; max-width: 1200px; margin: 2rem auto; border-radius: var(--border-radius);
    overflow: hidden; box-shadow: var(--shadow-md); border: 1px solid var(--glass-border);
    background: var(--glass-bg); backdrop-filter: blur(var(--blur-intensity)); -webkit-backdrop-filter: blur(var(--blur-intensity));
    display: flex; flex-direction: column;
    transition: background var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease, box-shadow var(--theme-transition-duration) ease;
}

/* Custom Scrollbar */
::-webkit-scrollbar { width: var(--scrollbar-width); }
::-webkit-scrollbar-track { background: hsla(var(--hue), 10%, 50%, 0.1); border-radius: calc(var(--scrollbar-width) / 2); }
::-webkit-scrollbar-thumb { background: hsla(var(--hue), var(--primary-sat), calc(var(--primary-lig) - 10%), 0.6); border-radius: calc(var(--scrollbar-width) / 2); transition: background var(--theme-transition-duration) ease; }
::-webkit-scrollbar-thumb:hover { background: hsla(var(--hue), var(--primary-sat), var(--primary-lig), 0.8); }

.header {
    padding: 2rem; text-align: center; background: var(--glass-bg-header); backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px);
    border-bottom: 1px solid var(--glass-border);
    transition: background var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease;
}
.header h1 { font-weight: 600; color: var(--text); margin-bottom: 0.5rem; font-size: clamp(1.8rem, 5vw, 2.5rem); text-shadow: 0 1px 2px rgba(255, 255, 255, 0.05); transition: color var(--theme-transition-duration) ease; }
.header p { color: var(--text-light); font-size: clamp(0.85rem, 2vw, 0.95rem); font-weight: 500; transition: color var(--theme-transition-duration) ease; }

.content-area {
     flex: 1; padding: 1.5rem; background: var(--glass-bg-content); backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); overflow-y: auto;
     transition: background var(--theme-transition-duration) ease;
}

/* Tabs */
.tab-container { margin-bottom: 20px; }
.tab-buttons { display: flex; gap: 5px; margin-bottom: 20px; border-bottom: 1px solid var(--glass-border-light); transition: border-color var(--theme-transition-duration) ease; }
.tab-btn { background: none; border: none; padding: 12px 18px; cursor: pointer; font-size: 1em; color: var(--text-light); position: relative; transition: color var(--theme-transition-duration) ease; }
.tab-btn::after { content: ''; position: absolute; left: 50%; bottom: 0; width: 0; height: 3px; background: var(--primary); border-radius: 2px; transition: width 0.3s ease, left 0.3s ease, background-color var(--theme-transition-duration) ease; }
.tab-btn:hover { color: var(--primary); }
.tab-btn.active { color: var(--primary); font-weight: 600; }
.tab-btn.active::after { width: 80%; left: 10%; }
.tab-content { display: none; padding-top: 10px;}
.tab-content.active { display: block; animation: fadeIn 0.5s ease; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

/* Skeleton Loading */
.skeleton-list { display: grid; grid-template-columns: repeat(auto-fit,minmax(300px,1fr)); gap: 15px; margin-top: 20px; transition: opacity 0.3s ease; }
.skeleton-card { height: 240px; border-radius:var(--border-radius); background: var(--glass-bg-card); position: relative; overflow: hidden; border: 1px solid var(--glass-border); transition: background var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease; }
.skeleton-card::after { content: ""; position: absolute; top:0; left:-150%; width: 100%; height:100%; background: linear-gradient(90deg, transparent, hsla(var(--hue), 15%, var(--glass-lightness), calc(var(--glass-alpha) + 0.08)), transparent); animation: shimmer 1.5s infinite cubic-bezier(0.4, 0.0, 0.2, 1); transition: background var(--theme-transition-duration) ease; }
@keyframes shimmer { to { transform: translateX(250%); } }

/* Task List */
#task-list { margin-top: 20px; display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 15px; }
.task-item {
    background: transparent;
    border: none;
    border-left-width: 5px;
    border-radius: var(--border-radius);
    padding: 0;
    display: flex; flex-direction: column; border-left-color: var(--primary);
    opacity: 0; transform: translateY(15px);
    transition: opacity 0.6s cubic-bezier(0.34, 1.56, 0.64, 1),
                transform 0.6s cubic-bezier(0.34, 1.56, 0.64, 1),
                box-shadow 0.3s ease,
                border-left-color 0.3s ease,
                background var(--theme-transition-duration) ease,
                border-color var(--theme-transition-duration) ease;
    perspective: 800px; will-change: opacity, transform;
    position: relative;
    box-shadow: var(--shadow-sm), 0 2px 8px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 10%), 0.03);
}
/* Fine inner border (ensure it doesn't block clicks) */
.task-item::after {
  content: '';
  position: absolute;
  inset: 1px;
  border: 1px solid hsla(var(--hue), 30%, calc(100% - var(--text-base-lig)), 0.1);
  border-radius: calc(var(--border-radius) - 1px);
  pointer-events: none; /* Should allow clicks through */
  transition: border-color var(--theme-transition-duration) ease;
}
.task-item.in-view { opacity: 1; transform: translateY(0); }

/* Inner Wrapper for Content and Background */
.task-item-inner {
    padding: 20px; display: flex; flex-direction: column; gap: 15px; width: 100%; height: 100%;
    background: linear-gradient(145deg, var(--glass-bg-card), hsla(var(--hue), 20%, calc(var(--glass-lightness) - 3%), calc(var(--glass-alpha) + 0.01)));
    border-radius: var(--border-radius);
    transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1),
                background var(--theme-transition-duration) ease;
    transform-style: preserve-3d; will-change: transform;
    position: relative; /* Ensure z-index takes effect */
    z-index: 2; /* Increase z-index to be above potential overlays like ::after */
}

.task-item:hover { box-shadow: 0 8px 25px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 15%), 0.15), 0 4px 12px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 10%), 0.05); }
.task-item:hover .task-item-inner { transform: rotateX(4deg) rotateY(-4deg) translateZ(10px) translateY(-4px); }
/* Status colors */
.task-item.overdue { border-left-color: var(--danger); }
.task-item.warning { border-left-color: var(--warning); }
.task-item.normal { border-left-color: var(--primary); }
.task-item.date-today { border-left-color: hsl(var(--hue), var(--primary-sat), calc(var(--primary-lig) + 10%)); }

/* Task Category Tag */
.task-category-tag {
  height: 4px; width: 40%; border-radius: 2px; margin-bottom: 12px; background: var(--primary);
  transition: background-color var(--theme-transition-duration) ease;
}
.task-item.overdue .task-category-tag { background: var(--danger); }
.task-item.warning .task-category-tag { background: var(--warning); }
.task-item.date-today .task-category-tag { background: hsl(var(--hue), var(--primary-sat), calc(var(--primary-lig) + 10%)); }

.task-header { display: flex; justify-content: space-between; align-items: flex-start; gap: 15px; padding-bottom: 10px; border-bottom: 1px dashed var(--glass-border-light); transition: border-color var(--theme-transition-duration) ease; }
.task-title { font-size: clamp(1rem, 2.5vw, 1.15rem); font-weight: 600; color: var(--text); word-break: break-word; flex-grow: 1; transition: color var(--theme-transition-duration) ease; }
.task-status { font-size: 0.85em; font-weight: 500; padding: 4px 10px; border-radius: var(--border-radius); white-space: nowrap; color: white; background-color: var(--primary); transition: background-color var(--theme-transition-duration) ease, color var(--theme-transition-duration) ease; }
.task-status.status-overdue { background-color: var(--danger); }
.task-status.status-warning { background-color: var(--warning); color: hsl(var(--hue), 15%, 15%); }
.task-status.status-normal { background-color: var(--primary); }
.task-status.status-date-today { background-color: hsl(var(--hue), var(--primary-sat), calc(var(--primary-lig) + 10%)); color: hsl(var(--hue), 15%, 15%); }

.task-details { display: flex; flex-direction: column; gap: 8px; font-size: 0.9em; color: var(--text-light); transition: color var(--theme-transition-duration) ease; }
.detail-row { display: flex; justify-content: space-between; gap: 10px; word-break: break-word; font-size: clamp(0.8rem, 1.8vw, 0.9rem); }
.detail-label { font-weight: 600; color: hsl(var(--hue), 15%, calc(var(--text-base-lig) + 10%)) !important; flex-shrink: 0; width: 80px; text-align: left; transition: color var(--theme-transition-duration) ease; }
.detail-value { flex-grow: 1; text-align: right; color: var(--text) !important; }
.detail-row.full-width { flex-direction: column; gap: 5px; border-top: 1px dashed var(--glass-border-light); padding-top: 10px; margin-top: 5px; transition: border-color var(--theme-transition-duration) ease; }
.detail-row.full-width .detail-label { width: auto; text-align: left; font-weight: 600; }
.detail-row.full-width .detail-value { text-align: left; font-style: italic; }

/* Collapsible Message Preview */
.message-preview { position: relative; max-height: 60px; overflow: hidden; cursor: pointer; transition: max-height 0.35s ease-in-out; font-style: normal; color: var(--text); background: hsla(var(--hue), 10%, 50%, 0.08); padding: 8px; border-radius: 6px; word-break: break-word; white-space: pre-wrap; padding-bottom: 20px; }
.message-preview.expanded { max-height: 500px; }
.message-preview::after { content: '点击展开'; position: absolute; bottom: 4px; right: 8px; background: hsla(var(--hue), 10%, calc(var(--text-base-lig) + 10%), 0.1); color: var(--text-light); padding: 2px 6px; font-size: 0.75em; border-radius: 4px; opacity: 0.8; transition: opacity 0.2s ease; }
.message-preview:hover::after { opacity: 1; }
.message-preview.expanded::after { content: '点击收起'; }
.message-preview:not(.expanded)[data-short="true"]::after { display: none; }

/* Task Progress Bar */
.progress-bar-container { height: 4px; width: 100%; background: hsla(var(--hue), 15%, 50%, 0.15); border-radius: 2px; margin-top: 10px; margin-bottom: 5px; overflow: hidden; transition: background-color var(--theme-transition-duration) ease; }
.progress-bar { height: 100%; background: var(--primary); border-radius: 2px; transition: width 0.6s cubic-bezier(0.645, 0.045, 0.355, 1), background-color var(--theme-transition-duration) ease; }
.task-item.overdue .progress-bar { background: var(--danger); }
.task-item.warning .progress-bar { background: var(--warning); }
.task-item.date-today .progress-bar { background: hsl(var(--hue), var(--primary-sat), calc(var(--primary-lig) + 10%)); }

.task-actions {
    display: flex; flex-wrap: wrap; gap: 10px; margin-top: 15px; padding-top: 15px;
    border-top: 1px dashed var(--glass-border-light); justify-content: flex-end;
    transition: border-color var(--theme-transition-duration) ease;
    position: relative; /* Ensure z-index takes effect */
    z-index: 3; /* Ensure buttons are definitely above other content within inner */
}

/* Explicitly ensure buttons are clickable */
.task-actions .btn {
    position: relative; /* Needed for z-index */
    z-index: 4; /* Highest z-index within the card */
    pointer-events: auto !important; /* Force pointer events */
}


.empty-state { text-align: center; padding: 40px 20px; color: var(--text-light); border: 2px dashed var(--glass-border); border-radius: var(--border-radius); background-color: hsla(var(--hue), 15%, var(--glass-lightness), calc(var(--glass-alpha) - 0.05)); grid-column: 1 / -1; transition: color var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease, background-color var(--theme-transition-duration) ease; }
.empty-state p { font-size: clamp(0.9rem, 2.2vw, 1.1em); margin-bottom: 10px; color: var(--text-light); transition: color var(--theme-transition-duration) ease;}
.empty-state .loading { margin-top: 15px; border-top-color: var(--primary); transition: border-top-color var(--theme-transition-duration) ease;}
#loader-container { display: flex; justify-content: center; align-items: center; min-height: 60px; margin-top: 15px; }
#loader { width: 50px; height: 50px; }

/* Buttons */
.btn { display: inline-block; color: white; border: none; padding: 10px 16px; border-radius: var(--border-radius); cursor: pointer; font-family: "LXGW WenKai Screen", sans-serif !important; font-size: 0.95em; font-weight: 500; text-align: center; box-shadow: var(--shadow-sm); text-decoration: none; position: relative; overflow: hidden; transition: background-color 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease, transform 0.2s ease; will-change: transform, box-shadow; }
.btn:hover { transform: scale(1.05); box-shadow: 0 4px 12px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 15%), 0.1); }
.btn:active { transform: scale(0.96); box-shadow: 0 1px 3px hsla(var(--hue), 30%, calc(var(--text-base-lig) - 15%), 0.1); }
.btn:disabled { background: hsla(var(--hue), 10%, 50%, 0.2); color: hsla(var(--hue), 10%, 50%, 0.5); cursor: not-allowed; box-shadow: none; opacity: 0.7; transform: none; }
.btn .ripple { position: absolute; border-radius: 50%; background: hsla(var(--hue), 100%, 98%, 0.5); transform: scale(0); animation: ripple-effect 0.6s ease-out; pointer-events: none; will-change: transform, opacity; }
@keyframes ripple-effect { to { transform: scale(4); opacity: 0; } }
.btn-primary {background-color: var(--primary);color: hsl(var(--hue), 25%, 15%) !important;}
.btn-primary:hover { background-color: hsl(var(--hue), var(--primary-sat), calc(var(--primary-lig) - 5%)); }
.btn-success { background-color: var(--success); color: hsl(var(--hue), 15%, 15%); }
.btn-success:hover { background-color: hsl(calc(var(--hue) - 20), var(--success-sat), calc(var(--success-lig) - 8%)); }
.btn-warning { background-color: var(--warning); color: hsl(50, 25%, 25%); }
.btn-warning:hover { background-color: hsl(50, var(--warning-sat), calc(var(--warning-lig) - 8%)); }
.btn-danger { background-color: var(--danger); color: hsl(0, 15%, calc(100% - var(--danger-lig) / 2)); }
.btn-danger:hover { background-color: hsl(0, var(--danger-sat), calc(var(--danger-lig) - 8%)); }
.btn-sm { padding: 6px 12px; font-size: 0.85em; border-radius: 8px; }

/* Modal */
.modal { visibility: hidden; opacity: 0; position: fixed; z-index: 1000; left: 0; top: 0; width: 100%; height: 100%; background-color: hsla(var(--hue), 30%, 5%, 0.5); overflow: auto; padding: 20px; backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px); transition: opacity 0.3s ease, visibility 0.3s ease, background-color var(--theme-transition-duration) ease; }
.modal.show { visibility: visible; opacity: 1; }
.modal-content { background-color: var(--glass-bg-content); margin: 5% auto; padding: 30px; border-radius: var(--border-radius); width: 95%; max-width: 550px; box-shadow: var(--shadow-md); position: relative; border: 1px solid var(--glass-border); backdrop-filter: blur(var(--blur-intensity)); -webkit-backdrop-filter: blur(var(--blur-intensity)); opacity: 0; transform: scale(0.9); transition: background var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease, box-shadow var(--theme-transition-duration) ease; }
.modal.show .modal-content { animation: modalEnter 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) forwards; }
@keyframes modalEnter { from { opacity: 0; transform: scale(0.9) translateY(10px); } to { opacity: 1; transform: scale(1) translateY(0); } }
.modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 25px; padding-bottom: 15px; border-bottom: 1px solid var(--glass-border-light); transition: border-color var(--theme-transition-duration) ease; }
.modal-header h2 { margin-bottom: 0; font-size: 1.6em; color: var(--text); transition: color var(--theme-transition-duration) ease; }
.close { color: var(--text-light); font-size: 28px; font-weight: bold; cursor: pointer; line-height: 1; background: none; border: none; padding: 5px; transition: color 0.2s ease; }
.close:hover { color: var(--danger); }

/* Forms */
.form-group { margin-bottom: 20px; }
.form-group label { display: block; margin-bottom: 8px; font-weight: 600; font-size: 0.95em; color: hsl(var(--hue), 15%, calc(var(--text-base-lig) + 10%)) !important; transition: color var(--theme-transition-duration) ease; }
.form-control { width: 100%; padding: 12px; border: 1px solid var(--glass-border); border-radius: var(--border-radius); font-size: 1em; background-color: hsla(var(--hue), 15%, var(--glass-lightness), calc(var(--glass-alpha) + 0.02)); color: var(--text); transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease, color var(--theme-transition-duration) ease; }
.form-control:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px hsla(var(--hue), var(--primary-sat), var(--primary-lig), 0.2); background-color: hsla(var(--hue), 15%, var(--glass-lightness), calc(var(--glass-alpha) + 0.05)); }
textarea.form-control { min-height: 100px; resize: vertical; }
select.form-control {
  appearance: none;
  /* Default arrow color, will be updated by JS */
  background-image: url('data:image/svg+xml;utf8,<svg fill="%23333333" height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg"><path d="M7 10l5 5 5-5z"/></svg>');
  background-repeat: no-repeat;
  background-position: right 12px center;
  background-size: 16px 16px;
  padding-right: 40px;
}
.form-check { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.form-check label { margin-bottom: 0; font-weight: normal; cursor: pointer; color: hsl(var(--hue), 15%, calc(var(--text-base-lig) + 20%)) !important; transition: color var(--theme-transition-duration) ease; }
.form-check input[type="checkbox"] { width: auto; height: 1.1em; width: 1.1em; cursor: pointer; accent-color: var(--primary); }
#task-form button[type="submit"] { width: 100%; padding: 12px; font-size: 1em; }

/* Messages & Loading */
#message { margin-top: 20px; padding: 12px 15px; border-radius: var(--border-radius); text-align: center; display: none; animation: fadeIn 0.3s ease; font-size: 0.9em; font-weight: 500; transition: background-color var(--theme-transition-duration) ease, color var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease; }
.message-success { background-color: hsla(calc(var(--hue) - 20), var(--success-sat), calc(var(--success-lig) - 5%), 0.2); color: hsl(calc(var(--hue) - 20), calc(var(--success-sat) + 10%), calc(var(--success-lig) - 30%)); border: 1px solid hsla(calc(var(--hue) - 20), var(--success-sat), calc(var(--success-lig) - 5%), 0.3); }
.message-error { background-color: hsla(0, var(--danger-sat), calc(var(--danger-lig) - 5%), 0.15); color: hsl(0, var(--danger-sat), calc(var(--danger-lig) - 15%)); border: 1px solid hsla(0, var(--danger-sat), calc(var(--danger-lig) - 5%), 0.2); }
.message-info { background-color: hsla(var(--hue), 10%, 50%, 0.1); color: var(--text); border: 1px solid hsla(var(--hue), 10%, 50%, 0.15); }
.message-warning { background-color: hsla(50, var(--warning-sat), calc(var(--warning-lig) - 10%), 0.15); color: hsl(50, var(--warning-sat), calc(var(--warning-lig) - 40%)); border: 1px solid hsla(50, var(--warning-sat), calc(var(--warning-lig) - 10%), 0.2); }
.loading { display: inline-block; width: 24px; height: 24px; border: 3px solid hsla(var(--hue), 10%, 50%, 0.2); border-radius: 50%; border-top-color: var(--primary); animation: spin 1s ease-in-out infinite; vertical-align: middle; transition: border-color var(--theme-transition-duration) ease, border-top-color var(--theme-transition-duration) ease; }
@keyframes spin { to { transform: rotate(360deg); } }

/* Footer */
.footer { text-align: center; padding: 1.5rem; background: var(--glass-bg-header); color: var(--text-light); margin-top: auto; backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); border-top: 1px solid var(--glass-border); font-size: 0.9rem; transition: background var(--theme-transition-duration) ease, color var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease; }
.footer a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
.footer a:hover { color: hsl(var(--hue), var(--primary-sat), calc(var(--primary-lig) + 5%)); text-decoration: underline; }

/* Theme Switcher */
.theme-switcher { position: fixed; bottom: 20px; right: 20px; display: flex; gap: 8px; z-index: 100; background: hsla(var(--hue), 15%, var(--glass-lightness), calc(var(--glass-alpha) + 0.05)); padding: 8px; border-radius: 16px; box-shadow: var(--shadow-sm); border: 1px solid var(--glass-border); backdrop-filter: blur(4px); transition: background var(--theme-transition-duration) ease, border-color var(--theme-transition-duration) ease; }
.theme-option { width: 24px; height: 24px; border-radius: 50%; cursor: pointer; border: 2px solid hsla(0, 0%, 100%, 0.5); box-shadow: 0 1px 4px hsla(var(--hue), 30%, 10%, 0.15); transition: transform 0.2s ease, box-shadow 0.2s ease; }
.theme-option:hover { transform: scale(1.15); }
.theme-option.active { transform: scale(1.1); border-color: white; box-shadow: 0 0 0 2px hsla(var(--hue), var(--primary-sat), var(--primary-lig), 0.7), 0 2px 6px hsla(var(--hue), 30%, 10%, 0.2); }

/* Responsiveness */
@media (max-width: 768px) { .container { width: 100%; margin: 1rem auto; } .header { padding: 1.5rem; } .content-area { padding: 1rem; } .task-item-inner { padding: 15px; } .theme-switcher { bottom: 10px; right: 10px; padding: 6px; gap: 6px; } .theme-option { width: 20px; height: 20px; } .modal-content { width: 95%; margin: 10% auto; padding: 20px; } .modal-header h2 { font-size: 1.4em; } }
@media (max-width: 480px) { body { padding: 10px; } .container { margin: 0.5rem auto; } .header { padding: 1rem; } .content-area { padding: 0.8rem; } #task-list { grid-template-columns: 1fr; } .task-item-inner { padding: 12px; } .detail-row { flex-direction: column; align-items: flex-start; gap: 2px; } .detail-label { width: auto; text-align: left; } .detail-value { text-align: left; } .task-actions { justify-content: space-around; } .btn { padding: 8px 12px; font-size: 0.9em; } .btn-sm { padding: 5px 10px; font-size: 0.8em; } .modal-content { padding: 15px; } .modal-header h2 { font-size: 1.2em; } }

/* Screen Reader Only */
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border-width: 0; }